BG1.2
Presentations: Wed, 25 May | Room C
Wildfires remove well-developed vegetation but restore it from an ecological point of view, although they are often called disasters when their intensity and extent in forests are large. Thermochemical decomposition of organic material at high temperatures (200 - 750 °C) in the absence of oxygen (or any halogen) to decompose biosolids has been recognised as a method with numerous benefits for waste management, carbon sequestration and sustainable agriculture. The effects of pyrogenic carbon (PyC) from wildfire and from the laboratory are believed to be different. The evidence to date is informative in bridging pyrogenic carbon from wildfire and pyrolysis, including aspects of: 1) PyC as a microsite for microbial communities; 2) the role of PyC of different sizes in soil aggregation; 3) the role of the soil microbiome in soil aggregation; 4) nutrient release - phosphorus availability in PyC. Future work is needed to investigate 1) the role of nano- or micro-sized PyC in the guts of soil fauna - nutrient uptake and function of the microbiome; 2) linking municipal biowaste to carbon sequestration; 3) improving efficiency in composting and vermicomposting; and 4) negative impacts on soil fauna such as earthworms. Knowledge of PyC in materials science, waste management and environmental microbiology offers opportunities to make breakthroughs in biowaste management and climate change mitigation.
How to cite: Sun, D.: Pyrogenic carbon from wildfire or from the laboratory , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2442, https://doi.org/10.5194/egusphere-egu22-2442, 2022.
Paddy stubble burning is a major environmental issue that plagues the ambient air quality of the Indo-Gangetic Plain. Every year, during the post-monsoon season (October and November), approximately 17 million tons of paddy stubble are burnt openly in the fields of Punjab and Haryana. Over two months, this large-scale biomass burning results in persistent smog and severely perturbs the regional air quality. The emission of reactive gaseous pollutants like volatile organic compounds (VOCs) from this source drive the surface ozone and aerosol formation. However, there is a considerable knowledge gap regarding their identification, amounts and spatial distribution over North India. Widely used top-down global fire emission inventories like GFED, GFAS and FINN rely on the high-resolution MODIS and VIIRS satellite fire products. However, they are severely constrained by the missed fires, limited VOC speciation and uncertain biomass burnt calculations due to non-region-specific emission and land use parametrization factors. The current bottom-up emission estimates also have high uncertainties because of non-region-specific emission factors and burning practices. This work presents a new “hybrid” gridded emission inventory for paddy stubble burning over Punjab and Haryana in 2017 at 1 km × 1 km spatial resolution. First, the emission factors (EFs) of 77 VOCs were measured in smoke samples collected from the on-field paddy fires of Punjab. These were then combined with 1 km × 1 km stubble burning activity, constrained by annual crop production yields, regional rice cultivars, burning practices and satellite-detected fire radiative power. The results revealed that paddy stubble burning is a significant source of oxygenated VOCs like acetaldehyde (37.5±9.6 Ggy-1), 2-furaldehyde (37.1±12.5 Ggy-1), acetone (34.7±13.6 Ggy-1), and toxic VOCs like benzene (9.9±2.8 Ggy-1) and isocyanic acid (0.4±0.2 Ggy-1). These compounds are also significantly underestimated and unaccounted for by existing top-down and bottom-up emission inventories. Additionally, it was found that the emissions of NMVOC (346±65 Ggy-1), NOx (38±8 Ggy-1), NH3 (16±4 Ggy-1), PM2.5 (129±9 Ggy-1), GHG CO2 equivalents (22.1±3.7 Tgy-1) from paddy stubble were up to 20 times higher than the corresponding emissions from traffic and municipal waste burning over north-west India during October and November 2017. Mitigation of this source alone can yield massive air-quality climate co-benefits for more than 500 million people.
How to cite: Kumar, A., Hakkim, H., Sinha, B., and Sinha, V.: Gridded 1 km × 1 km emission inventory for paddy stubble burning emissions over north-west India constrained by measured emission factors of 77 VOCs and district-wise crop yield data, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2565, https://doi.org/10.5194/egusphere-egu22-2565, 2022.
Crop residue burning in china increased significantly in the last decade, especially it took up a majority in Northeast China, which plays an important role of severe haze pollution. Hence, two main types of crop residues (corn and rice straw) were chosen to characterize the particle number concentration, chemical components of fine particulate matter and optical properties of carbonaceous aerosols by a suite of fast-response online portable instruments, together with offline sampling and analysis, during the field-based combustion experiments in Northeast China. For the range of 0.25 and 2.5 µm, more particles were emitted from rice straw burning than those from corn straw burning, and the time-averaged number concentration of particles during the flaming process was approximately 2 times higher than that during the smoldering process for these two straws. Organic carbon (OC), elemental carbon (EC) and water-soluble ions were the most abundant components and accounted for 42.5±7.5%, 7.7±1.7% and 18.0±3.4% of the PM2.5, respectively. Furthermore, rice straw burning emitted higher OC and lower Cl- and K+ than those from corn straw burning. The average absorption Ångström exponent (AAE) of carbonaceous aerosols was 2.1±0.3, while the AAE of brown carbon (BrC) was 4.7±0.4 during the whole burning process. On average, BrC contributed to 63% and 20% of the total light absorption at 375 nm and 625 nm, respectively. Parameterization of BrC absorption revealed that the fraction of absorption from BrC has a reasonably good correlation with EC/OC (-0.84) and AAE (0.94) at 375 nm. Generally, combustion conditions can affect the optical properties of carbonaceous aerosols, and a negative correlation (-0.77) was observed between the AAE and modified combustion efficiency; in addition, the percentage of absorption due to BrC were lower at the flaming phase. To explorer the spatial and temporal variability of open agricultural burning in Northeast China from 2014 to 2019, the emission inventory of key gaseous and particle pollutants was established, which derived from a combination of geostationary (Himawari) and polar (VIIRS) orbiter fire radiative power products.
How to cite: Wang, L., Wang, Q., Cheng, M., Zhang, T., and Xin, J.: Emission characteristics of atmospheric pollutants from field-scale crop residue burning in Northeast China, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4095, https://doi.org/10.5194/egusphere-egu22-4095, 2022.
Fire is an important Earth system process and the largest source of global primary carbonaceous aerosols. Earlier studies have focused on the influence of fire aerosols on radiation, surface climate, air quality, and biogeochemical cycle. The impact of fire aerosols on the global water cycle has not been quantified and related mechanisms remain largely unclear. This study provides the first quantitative assessment and understanding of the influence of fire aerosols on the global water cycle. This is done by quantifying the difference between simulations with and without fire aerosols using the fully-coupled Community Earth System Model (CESM). Results show that presentday fire aerosols weaken the global water cycle significantly. They decrease the continental precipitation, evapotranspiration, and runoff by 4.1±1.8, 2.5±0.5, and 1.5±1.4 ×103 km3 yr-1 as well as ocean evaporation, precipitation, and water vapor transport from ocean to land by 8.1±1.9, 6.6±2.3, and 1.5±1.4 ×103 km3 yr-1. The impacts of fire aerosols are most clearly seen in the tropics and the Arctic-boreal zone. Fire aerosols affect the global water cycle mainly by cooling the surface which reduces ocean evaporation, land soil evaporation and plant transpiration. The decreased water vapor load in the atmosphere leads to a decrease in precipitation, which contributes to reduced surface runoff and sub-surface drainage.
How to cite: Li, F., Lawrence, D., Jiang, Y., and Liu, X.: Fire aerosols slow down the global water cycle, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4394, https://doi.org/10.5194/egusphere-egu22-4394, 2022.
Ever-increasing wildfires in scale and duration have resulted in enormous human and material losses, and adverse health outcomes due to short- and long-term exposure to diverse air pollutants emitted from fires. Historically, the Mediterranean Basin, characterized by hot and dry summers, has been particularly affected by wildfires, and the situation is deteriorating as climate change worsens and the regional populations grow rapidly. To assess the health impacts due to short-term exposure to air pollution caused by the 2021 summer wildfires in eastern and central Mediterranean Basin, we demonstrate a multi-pollutant approach based on the Weather Research and Forecasting online-coupled Chemistry (WRF-Chem) model. The WRF-Chem model was used to simulate concentrations of major air pollutants such as fine particulate matter (PM2.5), SO2, NO2, and O3, in a fire and no-fire scenario. Elevated short-term exposure of the population to air pollutants were associated with excess all-cause mortality using relative risks (RRs) for individual pollutants based on previously published meta-analyses.
Our estimates indicate that the additional short-term exposure to O3, which is predicted to increase due to the wildfires, resulted in the highest number of excess deaths of 608 (95% CI: 456-771) over the entire region of investigation during the wildfire season between mid-July to early October 2021. This is followed by 270 (95% CI: 177- 370) excess deaths due to elevated PM2.5 exposure, rendering the health effect of increased O3 from wildfires larger than the effect of increased PM2.5. This is shown to be largely reasoned by the spatially more widespread impact of wildfires on O3. In contrast, the excess mortality caused by NO2 and SO2 emitted from wildfires is estimated low. This may be ascribed to the different sources of air pollutants, with NO2 a marker of traffic, while SO2 originating primarily from emissions from fossil fuel combustion, e.g., from power plants. Our study concludes with a discussion on uncertainties associated with the multi-pollutant health impact assessment and suggests a critical scrutiny of estimates based thereupon.
How to cite: Zhou, B. and Knote, C.: Multi-pollutant assessment of health impacts of 2021 summer wildfires in eastern and central Mediterranean Basin, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7258, https://doi.org/10.5194/egusphere-egu22-7258, 2022.
Fine particulate matter with a diameter of ≤ 2.5 (PM2.5), one of the hazardous air pollutants, contributed 4.5 million to 8.9 million global mortality annually. Among the total PM2.5 related mortality, 5%–21% were attributed to fires. While anthropogenic fire has been declined by reduced land fragmentation and changed land use, climate change has increased fire activities especially in fire seasons. These fires eventually lead to high PM2.5 in many regions, leading to public health concern. However, the impact of future fires on PM2.5 and its health burden according to climate change and socioeconomic scenarios has not been studied globally. We estimated fire related PM2.5 at the end of 21st century under various future scenarios (combination of Shared Socioeconomic Pathways (SSPs) and Representative Concentration Pathways (RCPs)) and its attributable mortality. We used modified CLM and GEOSChem for simulating fire emissions and PM2.5 concentration, respectively. The Global Burden of Disease (GBD) method was used for estimating attributable mortality. We also evaluated how global inequality in fire-PM2.5 mortality by income (economic inequality) would change. We found that future climate change led to higher fire-PM2.5 by increasing drought and biomass carbon density, whereas future increased GDP would offset the increase in fire-PM2.5. The results of fire-PM2.5 mortality varied significantly by SSPs. Population increase under SSP3 would lead to increase in mortality and economic inequality. The total fire-PM2.5 mortality decreased under SSP1–4, but the economic inequality increased under SSP4. If the world follows SSP1-RCP2.6 scenario, fire-PM2.5 mortality would reduce about 40% and improve economic equality.
This research was supported by the Environment Research and Technology Development Fund (JPMEERF20202002) of the Environmental Restoration and Conservation Agency of Japan.
How to cite: Park, C., Takahashi, K., Fujimori, S., Li, F., Phung, V. L. H., Takakura, J., Hasegawa, T., and Ito, A.: Future fire impact on PM2.5 pollution and attributable mortality, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11223, https://doi.org/10.5194/egusphere-egu22-11223, 2022.
Fires across the Arctic-boreal zone (ABZ) play an important role in the boreal forest succession, permafrost thaw, and the regional and global carbon cycle and climate. These fires occur mainly in summer with large interannual variability. Previous studies primarily focused on the impacts of local surface climate and tropical El Niño-Southern Oscillation (ENSO). This study, for the first time, comprehensively investigates the influence of summer leading large-scale atmospheric teleconnection patterns in the Northern Hemisphere extra-tropics on interannual variability of ABZ fires. We use correlation and regression analysis of 1997–2019 multiple satellite-based products of burned area and observed/reanalyzed climate data. Results show that eight leading teleconnection patterns significantly affect 63±2% of burned areas across the ABZ. Western North America is affected by the East Pacific/North Pacific pattern (EP/NP) and the West Pacific pattern (WP); boreal Europe by the Scandinavia pattern (SCA); eastern North America, western and central Siberia, and southeastern Siberia by the North Atlantic Oscillation (NAO); and eastern Siberia /Russian Far East by the East Atlantic pattern (EA). NAO/EA induces lower-tropospheric drier northwesterly/northerly airflow passing through the east of boreal North America/Eurasia, which decreases surface relative humidity. Other teleconnections trigger a high-pressure anomaly, forcing downward motion that suppresses cloud formation and increases solar radiation reaching the ground to warm the surface air as well as brings drier air downward to reduce surface relative humidity. The drier and/or warmer surface air can decrease fuel wetness and thus increase burned area. Our study highlights the important role of the extra-tropical teleconnection patterns on ABZ fires, which is much stronger than ENSO that was thought to control interannual variability of global fires. It also establishes a theoretical foundation for ABZ fire prediction based on extra-tropical teleconnections, and has the potential to facilitate ABZ fire prediction and management.
How to cite: Zhao, Z., Lin, Z., Li, F., and Rogers, B. M.: Influence of Atmospheric Teleconnections on Interannual Variability of Arctic-boreal Fires, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4831, https://doi.org/10.5194/egusphere-egu22-4831, 2022.
Wildfire activity in Siberia (60E-180E, 55N-80N) has been observed to be more frequent and stronger in recent years. To understand the underlying mechanism of the positive trend in the frequency and strength of wildfire events, especially the role of lightning, we analyzed the relationship among fire ignition, Convective Available Potential Energy (CAPE), precipitation, and lightning flash density over Siberia using observations and reanalysis products for the period 2012–2020. A similar analysis was performed on an ultra-high-resolution (25-km) climate model simulation made with Community Earth System Model version 1.2.2 (CESM) under a greenhouse gas-induced warming scenario. In the observations, we found that while the number of lightning flashes is proportional to CAPE and precipitation, the number of fire ignition is only proportional to CAPE. In particular, we identified a threshold of 3.5 mm/day of precipitation, below which fire ignition occurs more frequently. Our analyses reveal that precipitation plays a role in suppressing fire ignition, but dry lightning with high CAPE and low precipitation effectively cause fire ignitions. In the CESM simulation, we found a robust increase in the number of days with high CAPE (> 700 J/kg) and low precipitation (< 3.5 mm/day), which suggests an increase in the frequency of dry lightning events, and therefore more lightning-induced wildfire events in Siberia.
How to cite: Kim, J.-S., Min, S.-K., Seong, M.-G., Kim, D., Holzworth, R., Koo, J.-H., Timmermann, A., and Schaepman-Strub, G.: Siberian fire ignition caused by the dry lightning activity, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3927, https://doi.org/10.5194/egusphere-egu22-3927, 2022.
The terrestrial biosphere is exposed to land use and anthropogenic climate change, which not only affects vegetation dynamics, but also changes land-atmosphere feedbacks. In particular, tropical rainforests are endangered by anthropogenic activities and are recognized as one of the terrestrial tipping elements. An ecosystem regime change to a new state could have profound impacts on regional and global climate, once the biome has transitioned from a forest into a savanna or grassland state. Fire is a potentially major driver in the position of the transition boundary and could hence impact the dynamic equilibrium between these possible vegetation states under a changing climate. However, systematic tests of fire-controlled tipping points and hysteretic behaviour using comprehensive Earth system models are still lacking.
Here, we specifically test the recovery of the Amazon rainforest after a complete deforestation at different atmospheric CO2 levels, by using the Earth system model CM2Mc-LPJmL v1.0 with a state-of-the-art representation of vegetation dynamics and fire. We find that fire prevents large-scale forest regrowth after complete deforestation and locks large parts of the Amazon in a stable grassland state. While slightly elevated atmospheric CO2 values had beneficial effects on the forest regrowth efficiency due to the fertilization effect, larger CO2 amounts further hampered the regrowth due to increasing heat stress. In a no-fire control experiment the Amazon rainforest recovered after 250 years to nearly its original extent at various atmospheric CO2 forcing levels. This study highlights the potential of comprehensive fire-enabled Earth system models to investigate and quantify tipping points and their feedback on regional and global climate.
How to cite: Drüke, M., von Bloh, W., Sakschewski, B., Lucht, W., and Thonicke, K.: Fire prevents the regrowth of the Amazon rainforest after complete deforestation in a fire-enabled Earth system model, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4551, https://doi.org/10.5194/egusphere-egu22-4551, 2022.
Fire modifies vegetation spectral reflectances in the optical, thermal and microwave domains due to the changes it induces in vegetation canopy components (leaves, needles, branches) and in soil properties. Freely available satellite-derived (Landsat) Vegetation Indices (VIs) and PALSAR Mosaic backscatter measurements (known to be sensitive to vegetation structure) were used to help understand vegetation properties (species richness, basal area) in relation to fire return time (FRT) across a range of tropical biomes (open savanna, savanna forest, evergreen forest, peat-swamp forest) in Mato Grosso (Brazil), Kruger National Park (South Africa) and Central Kalimantan (Indonesia).
For each site, we combined: (i) post-fire Landsat imagery (30 m) to derive VIs sensitive to vegetation diversity with (ii) PALSAR (25 m) backscatter that employes a longer wavelength (21 cm) and dual polarisation (Horizontal-Horizontal, Horizontal-Vertical) enabling the capture of strong backscattering of signal by branches and trunks.
Most of the Landsat VI values showed greater variability in forests compared to open savanna, reflecting the greater diversity in species’ composition and growth form. A strong positive relationship was found between VIs and FRT across biomes and especially in forests. The amount of vegetation burned per fire as recorded by the magnitude of changes in these VIs, was highest in annual burn regimes (FRT = 1 year). Green and red-edge bands provided better discrimination of vegetation species richness and basal area. A significant positive relationship to basal area in response to fire return time was also found using PALSAR data due to its deeper canopy penetration level and strong backscattering from woody components. The observed responses of VI- and PALSAR-inferred species’ richness and basal area in response to FRT in different tropical biomes suggest that the green and red-edge channels from optical and longer wavelength HV-backscatter are useful metrics to quantify post-fire tropical vegetation dynamics.
How to cite: Ningthoujam, R. K., Prestes, N. C. C. D. S., Andrade, M. F. D., Carniello, M. A., Coetsee, C. W., Harrison, M. E., Kusin, K., Rasul, A., Hoscilo, A., Pellegrini, A., Oliveras, I., Feldpausch, T. R., Page, S., Bloomfield, K. J., Harrison, S. P., and Prentice, I. C.: Remote sensing of tropical vegetation properties in response to fire return time, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6549, https://doi.org/10.5194/egusphere-egu22-6549, 2022.
Fires play a critical role in global biogeochemical and hydrological cycles through influencing vegetation succession and ecosystem functioning. Observational evidence shows that fire regimes across global ecosystems have been altered by climate change and human activities. However, most fire-enabled terrestrial biosphere models (TBMs) poorly capture the spatial and temporal patterns of fire ignitions, burned area, vegetation mortality and post-fire recovery. To improve our ability in predicting fire behavior and its impacts on the ecosystem and climate, it is essential to better represent fire-vegetation interactions in TBMs. Here, we improve the fire module of the Dynamic Land Ecosystem Model (DLEM-Fire) and optimize the parameters by using the satellite observed fire ignitions, burned area and leaf area index (LAI) products. Our results show that the improved fire model can describe the magnitude, spatial patterns, and interannual variations of burned area and vegetation mortality more accurately. Moreover, the model is capable of providing robust estimations of post-fire vegetation regeneration to characterize the vegetation resistance and resilience to fire disturbances. This study emphasizes the importance of integrating terrestrial biosphere models and satellite observation data for fire monitoring and prediction.
How to cite: Li, X., Tian, H., Yang, J., You, Y., and Pan, S.: Understanding and quantifying fire-vegetation interactions through integrating satellite observation data with the Dynamic Land Ecosystem Model (DLEM), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5893, https://doi.org/10.5194/egusphere-egu22-5893, 2022.
Wildfires have become a serious threat to ecosystems and human society over the last years of the 21st century, with many hectares being destroyed every year globally. The lengthening of the fire seasons and the increase of wildfires risk, which have been promoted by climate change, input many losses on society, economy and mostly in diverse ecosystems. In Portugal, the 2017 catastrophic fire season burned more than 450,000 hectares and caused the death of more than 100 people. In this context, relying on remotely sense products from MODIS collections, our study proposes an analysis of the effect of summer heat and water availability deficit in vegetation productivity decline that led to large fires propagation, especially in June and October of 2017. With the aim to evaluate the magnitude of the impact that compound or cascading extreme events had on the vegetation productivity decline, considering the 2001-2019 historical values, we defined three different classes of pixels that should reflect the conditions before the fire: affected by hot, by dry or by hot/dry conditions. Moreover, we assess the influence of favourable winter/spring meteorological conditions on enhancing vegetation productivity that promote high fuel accumulations susceptible to burn some months later. Our results reinforce the water and energy dependency of the vegetation of the region during the growing season and highlight that the combination of higher temperatures and water availability in spring can trigger summer wildfires propagation, flammability and intensity due to the accumulation of biomass. Considering that the example of 2017 can be more recurrent under the context of climate change, this study also highlights the need to improve the awareness strategies in fire prone regions like Portugal, especially on biomass accumulation control during growing season.
This study was supported by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under project FIRECAST (PCIF/GRF/0204/2017) and IMPECAF (PTDC/CTA-CLI/28902/2017).
How to cite: Ermitão, T., Gouveia, C., and Russo, A.: The Impacts of the 2017 Catastrophic Fire Season in Portugal on Vegetation Productivity, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8767, https://doi.org/10.5194/egusphere-egu22-8767, 2022.
Today's agriculture faces the challenge of safely feeding a growing population. This situation generates additional pressures on the environment such as increased organic waste generation, irrigated cropland and the consumption of mineral fertilizers. Moreover, in the present context of global warming, it is necessary to transform the linear economy into a circular economy, in which organic waste should be valorized and greenhouse gas emissions reduced. During the last decade the transformation of organic waste into biochar, the carbon-rich material produced during pyrolysis of biomass to be applied as soil ameliorant [1], to increase the amount of pyrogenic C at soils have been developed [2]. Here, green compost and biochar were produced from contrasting agricultural wastes and applied at greenhouse under limited irrigation conditions.
Results showed that raw material, together with the pyrolysis conditions, determined physical properties of biochars, and thus its performance as soil amendment. In all cases, an increase in the pyrogenic carbon content and a general improvement in the physical properties of agronomic interest of the technosoils were observed. However, the use of high doses of olive-pomace biochar negatively affected the germination due to its high salinity.
Biochar, although beneficial, is therefore not a universal solution and must be characterized, have the appropriate properties and be applied in a specific way to correct specific soil deficiencies.
Acknowledgements: The BBVA foundation is gratefully acknowledged for funding the scholarship Leonardo to “Investigadores y Creadores Culturales 2020” (Proyecto realizado con la Beca Leonardo a Investigadores y Creadores Culturales 2020 de la Fundación BBVA).
References:
[1] Campos, P., Miller, A., Knicker, H., Costa-Pereira, M., Merino, A., De la Rosa, J.M., 2020. Waste Manag., 105, 256-267.
[2] De la Rosa, J.M., Rosado, M., Paneque, M., Miller, A.Z., Knicker, H., 2018. Sci. Tot. Environ., 613-614, 969-976.
How to cite: De la Rosa, J. M., Campos, P., Santa-Olalla, A., Sanchez-Martín, Á., Miller, A., and Fernández-Boy, E.: Application of biochar to irrigated technosoils: Effects on germination and agronomic properties, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1916, https://doi.org/10.5194/egusphere-egu22-1916, 2022.
In this work, a multi-sensors temporal and spatial approach was carried out to monitor the vegetation post-fire recovery rate in a Mediterranean site (in part falling within the Nature2000 network) through the use of the optical Sentinel-2 and SAR C-band Sentinel-1 imagery temporal-series. The study area was observed for one year before and three years after the fire event. Several vegetation indices (VIs) were calculated for both optical (normalized difference vegetation index, NDVI; green NDVI, GNDVI; normalized red-edge vegetation index, NDRE, normal burn index, NBR; normalized difference water index, NDWI) and SAR (radar vegetation index, RVI; dual-polarized SAR vegetation index, DPSVI; radar forest degradation index, RFDI) data from which the temporal spectral profiles were extracted in the function of one of the three vegetation types (natural/semi-natural native forest, eucalyptus plantation and grasslands), of the burn-severity gradient, and of the orbit path of SAR satellite. What emerged is that the recovery spectral dynamics are highly influenced in terms of time and magnitude by both vegetation type and, mainly, burn severity. Optical Sentinel-2 observations showed that native woody and non-woody vegetation presented higher efficiency in restoring the ecological and physiological equilibrium by the observed time, whereas C-band SAR Sentinel-1 information seems to point out that the structural characteristics cannot be recovered in such a short time, although both the data appeared impacted by saturation. Climate variables, in particular monthly rainfall, compared and correlated with the temporal spectral profiles, demonstrated to be very influential on the SAR signal, especially for a higher degree of burn severity. The spatial distribution of the post-fire recovery rate was estimated by calculating the burn recovery ratio (BRR), optimized using the random forest (RF) machine learning regressor model to account the natural phenological changes which affect unburned vegetation during the time. The BRR results validated what had been recorded in the temporal profiles. The effectiveness of open-source data, software, and models interoperability for post-risk monitoring purposes of vulnerable habitats was also emphasized in this study.
How to cite: De Luca, G., Silva, J. M. N., and Modica, G.: Temporal and spatial analysis for post-fire vegetation recovery in a Mediterranean site. An approach using optical Sentinel-2 and SAR Sentinel-1 imagery., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12542, https://doi.org/10.5194/egusphere-egu22-12542, 2022.
Wildfires have become an imminent threat to ecosystems, consequently leading to economic loss and generating negative impacts on population health. Considering IPCC’s projection of a significant increase in the frequency of these events, it is important to understand which conditions lead to a fire intensification, as recently happened in California, Australia, and Brazilian Pantanal. Some of the greatest wildfires registered in North America and in Europe occurred in concomitance to intense heat waves and drought events. The lack of a comprehensive understanding of the physical mechanisms associated with extreme wildfire events in the Amazon rainforest, underlines the current inability to properly prevent them. Therefore, this study aimed to identify the role of extreme temperature events, such as heat waves (HW), in forest fires behaviour in the Brazilian Amazon during extreme drought years. The relationship between wildfires and HWs was hereby analysed during both dry and wet years in the Amazon Forest, in order to understand the association between different time and spatial scale events in forest fires magnitude. Accordingly, CPC/NOAA reanalysis data of daily maximum temperature between 1979 and 2019 were used as input to determine HW events in a multi-method global heatwave and warm-spell data record and analysis toolbox1. A standard HW definition was applied, where an event corresponds to at least three consecutive days in which the maximum temperature exceeds the 90th percentile for that day. Wildfire magnitude analyses were calculated through active fire (AF) and fire radiative power (FRP) data from MODIS C6 sensor, obtained at FIRMS/NASA for the comprehended period between 2003 and 2019. Spatial intensity of HW was classified and then confronted with precipitation anomaly in both normal and dry years. Also, statistical comparison of fire magnitude (i.e., AF and FRP) in HW and non heat wave (NHW) days was analysed to measure extreme temperature events impacts in wildfire. Results showed a significant increasing trend in HW occurrences in recent decades, with peaks in known drier years. An increase of AF counting and fire intensity was noticed during HW events. This latter effect appears even when the HW occurs during extremely dry seasons, such as happened at the Amazon Forest in 2005, 2010 and 2015. Extreme values of AF and FRP were a quarter higher in 2005, doubled in 2010 and tripled in 2015 at HW days when compared to NHW days.
References
[1] Raei, E., Nikoo, M., AghaKouchak, A. et al. GHWR, a multi-method global heatwave and warm-spell record and toolbox. Sci Data 5, 180206 (2018).
Acknowledgements
This study was supported by FAPERJ project number E26/202.714/2019. L. N. was supported by CNPq PIBIC number 160099/2021-8.
How to cite: Narcizo, L., Santos, F. L., Peres, L. F., Trigo, R., and Libonati, R.: The impact of heat waves in forest fires over the Amazon rainforest, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10772, https://doi.org/10.5194/egusphere-egu22-10772, 2022.
Forest fires are a recurrent ecological phenomenon in the Mediterranean basin. They induce molecular changes in soil organic matter (SOM) leading to immediate and long-term environmental consequences [1]. The SOM is of paramount importance as indicator of soil health [2]. Fire-induced changes in SOM include the alteration of biogenic chemical structures and the accumulation of newly formed ones, enhancing dynamics in the complex balance between the different C-types [2,3]. Therefore, understanding SOM molecular composition, before and after fire, is fundamental to monitor changes in soil health, as well as its natural or man-mediated recovery [3,4]. Our aim was to assess the molecular composition of organic matter in fire-affected leptosols, at two depths (0–2 and 2–5 cm) under different vegetation types located in the southwestern of Portugal (Aljezur, Algarve). The SOM characterization was conducted by analytical pyrolysis (Py-GC/MS), a technique based on the thermochemical breakdown of organic compounds in the absence of oxygen at elevated temperatures [5]. The Py-GC/MS has been found suitable for the structural characterization of complex organic matrices [4], providing detailed structural information of individual compounds considered fingerprinting of SOM. However, due to the relative high number of molecular compounds released by analytical pyrolysis, the use of graphical-statistical methods, such as van Krevelen diagrams, are usually applied to help monitoring SOM molecular changes produced by fire [3,4]. This work represents the first attempt to evaluate the fire effects in SOM using a detailed molecular characterisation of SOM under different vegetation canopies, recently affected by wildfire, in southern Portugal.
References:
[1] Naveh, Z., 1990. Fire in the Mediterranean – a landscape ecological perspective. In: Goldammer, J.G., Jenkins, M.J. (Eds.), Fire in Ecosystems Dynamics: Mediterranean and Northern Perspective. SPB Academic Publishing, The Hague.
[2] González-Pérez, J.A., González-Vila, F.J., Almendros, G., Knicker, H., 2004. The effect of fire on soil organic matter—a review. Environ. Int. 30, 855–870.
[3] Jiménez-Morillo, N.T., De la Rosa, J.M., Waggoner, D., et al., 2016. Fire effects in the molecular structure of soil organic matter fractions under Quercus suber cover. Catena 145, 266–273.
[4] Jiménez-Morillo, N.T.; Almendros, G.; De la Rosa, J.M.; et al., 2020. Effect of a wildfire and of post-fire restoration actions in the organic matter structure in soil fractions. Sci. Total Environ. 728, 138715.
[5] Irwin, W.J., 1982. Analytical pyrolysis—a comprehensive guide. In: Cazes, J. (Ed.), Chromatographic Science Series, 22: Chapter 6. Marcel Dekker, New York.
Acknowledgments: This work was funded by national funds through FCT–Fundação para a Ciência e a Tecnologia (EROFIRE project, ref. PCIF-RPG-0079-2018). This research was funded by the European Union through the European Regional Development Funds in the framework of the Interreg V A Spain-Portugal program (POCTEP) through the CILIFO (Ref.: 0753_CILIFO_5_E) and FIREPOCTEP (Ref.: 0756_FIREPOCTEP_6_E) projects. In addition, this research was funded by the EU-FEDER co-funded project MARKFIRE (ref. P20_01073) from Junta de Andalucía. A.Z.M was supported by a CEECIND/01147/2017 contract from FCT, and a Ramón y Cajal contract (RYC2019-026885-I) from the Spanish Government (Ministerio de Ciencia en Innovación – MCIN).
How to cite: Jiménez-Morillo, N. T., Miller, A. Z., Guiomar, N., De la Rosa, J. M., Barrocas-Dias, C., Manhita, A., and González-Pérez, J. A.: Molecular characterisation of soil organic matter under different burned vegetation canopies, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4571, https://doi.org/10.5194/egusphere-egu22-4571, 2022.
Forest fire research can comprise forest fire case studies, laboratory experiments, fire detection by ground sensors, unmanned aerial vehicles and satellites, development of fire behaviour models, fire danger forecast, fire risk assessment, and much more. Commonly used and accepted Canadian method for forest fire danger forecast is expressed as Fire Weather Index (FWI) uses weather data. The index estimates the danger of wildfire and is based on meteorological parameters (air temperature, air humidity, wind speed, and rainfall amount) referring to 12 UTC for that day at the meteorological station or on a numerical weather prediction model grid point.
Knowing how weather and soil interact and affect each other, we propose a new fire risk index based on the innovative Soil Index. Using open-access data, we collected different soil data such as soil temperature and soil moisture, land cover, vegetation, slope, etc. Since there are different types of vegetation and states, Leaf Area Index (LAI) and Normalized Difference Vegetation Index (NDVI) are considered as well. Being focused on forest fires, data about the burned area were also taken into account as well as the slope of the terrain for which the fire risk is calculated.
Since all mentioned data have a diverse horizontal and temporal resolution, we decided to group them by temporal resolution: static, semi-static, and dynamic data. Static data refers to data that rarely change (never or every few years; e.g. land cover). Semi-static data refers to data that vary weekly or monthly (e.g. LAI). Dynamic data group refers to data that is strongly influenced by weather conditions (like soil temperature) and varies every hour. Because of various horizontal resolutions, soil parameters are interpolated to the same horizontal grid. Soil parameters are analysed concerning historical forest fires in Croatia. Despite Soil Index being based on soil parameters, we compared it with Fire Weather Index using data records for historical forest fires in Croatia. Obtained results indicate that the soil index has a better prediction performance compared to FWI. This study also highlights that not only the meteorological environment but also soil conditions are important parameters for fire risk assessment.
How to cite: Škurić Kuraži, D., Nižetić Kosović, I., and Herceg Bulić, I.: Forest fire risk assessment with soil data in Croatia, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4271, https://doi.org/10.5194/egusphere-egu22-4271, 2022.
The fuel moisture content (FMC) is an important property to assess fire danger, to control fuel ignition and fire propagation. The wetting and drying rates of the fuels are driven by the fuel characteristics and weather conditions, being FMC strongly driven by solar radiation influencing fuel temperature in the highly exposed fuels. Usually, FMC is divided into Dead Fuel Moisture Content (DFMC) and Life Fuel Moisture Content (LFMC). LFMC is not easily estimated due to plants’ adaptation to drought and capacity of extracting water from soils that significantly vary among different vegetation species. Extreme climate events (such as droughts and heatwaves) are important factors addressed to fire danger assessment and related activities, due to their significant impacts on fuel conditions and in the vegetation status. High-impact mega-fires have been reported over areas where biomass and fuel accumulation present significant amounts. Therefore, the estimation LFMC is a useful approach to improve fire danger assessment, bringing also advantages in the study of the dynamics of biodiversity and biomass understory recovery.
Although LFMC in-situ measurements have limited spatial coverage and temporal sampling, the use of remote sensing data is essential to overcome space-time constraints and to develop methodological approaches to assess space-time LFMC variations over Portugal. Accordingly, to previous studies, LFMC estimation results improve when using a vegetation index together with the minimum temperature. The Leaf Area Index (LAI) is a quantitative measure of the amount of live green leaf material present in the canopy per unit ground surface. Since LAI and LFMC are interdependent variables with similar seasonal and interannual trends, it is possible to estimate LFMC based on LAI data.
The present work aims to obtain LFMC statistical model to pixel by pixel for Portuguese national scale, using LAI and Land Surface Temperature (LST) products, delivered by the EUMETSAT Land Surface Analysis Satellite Applications Facility (LSA SAF) and LFMC in-situ data for Atlantic Scrub that are routinely collected over 10 monitoring sites by AGIF (Agência para a Gestão Integrada de Fogos Rurais, IP).
Results revealed very good correlation values between LFMC in-situ data and LFMC estimated, ranging between 0.68 and 0.92, decreasing to values ranging from 0.30 and 0.90, highlighting the robustness of the model in the majority of the locations. These results vary spatially, being higher over the most sampled locations, as expected; and have the drawback of being site-specific. The influence of LAI is higher than the minimum of LST however being less important LST in the northeast of Portugal. Further work will focus on the assessment of the remote sensing-based LFMC estimations uncertainty and the linking of LFMC to fire danger and behavior.
Acknowledgments: This study was performed within the framework of the LSA-SAF, co-funded by EUMETSAT and was partially supported by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under project FIRECAST (PCIF/GRF/0204/2017) and by the 2021 FirEUrisk project funded by European Union’s Horizon 2020 research and innovation programme under the Grant Agreement no. 101003890).
How to cite: Alonso, C., Durão, R., and Gouveia, C.: Live fuel moisture content approach using satellite data for Portugal mainland, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10035, https://doi.org/10.5194/egusphere-egu22-10035, 2022.
We show likely substantial increases in burning by 2100 in Boreal and Tropical Forests irrespective of future emissions and after accounting for the (often considerable) uncertainties and biases in global fire and climate modelling. Rather than projecting future fire regimes directly, we used the ConFire Bayesian framework to model the likelihood of all possible future burning levels given historic fire and climate model performance. Driving the framework with bias-corrected outputs from four ISIMIP2b GCMs run under RCP2.6 and RCP6.0 accounts for uncertainties in future emissions and climate model projections.
While we forecast the potential for substantial shifts in fire regimes of much of the world by the end of the century, many show low likelihood given our confidence in the fire, vegetation and climate model projections. Tropical savannas show the largest potential for change, though without confidence in the direction of change due to uncertainty in future precipitation projections. An increase in dry fuel drives an increase in burnt area in northern Australia. However, this is not significant against uncertainty associated with present-day veg/fire model performance. There is a significant agreement for decreased burning in Southern Brazil, Uruguay and northern Argentina, and the US east coast under RCP2.6, but not RCP6.0.
We do show a high likelihood of drying fuel loads driving an increase in burning in Indonesia, Southern Amazon, central and eastern Siberian Taiga and many Arctic areas across RCPs. These areas are of particular concern given the potential to release the high carbon content of forests and peatlands irrecoverable carbon. Mitigating from RCP6.0 to 2.6 will likely alleviate some though not all of this burning. This is important for future mitigation planning and determining likely temperature and emission targets to avoid the worst impacts of fire in our warmer world.
How to cite: Kelley, D. I., Mathison, C., Burton, C., Brown, M., Sullivan, A., Baker, E., and Kurvits, T.: Likely future(s) of global wildfires, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-6512, https://doi.org/10.5194/egusphere-egu22-6512, 2022.
INFERNO human fire ignitions and fire suppression functions excluded the representation of socio-economic factors (aside population density) that can affect anthropogenic behaviour regarding fire ignitions. To address this, we implement a socio-economic factor in the fire ignition and suppression parametrisation in INFERNO based on an Human Development Index (HDI) term. The HDI is calculated based on three indicators designed to capture the income, health, and education dimensions of human development. Therefore, we assume this leads to a representation where if there is more effort in improving human development, there is also investment on higher fire suppression by the population. Including this representation of socio-economic factors in INFERNO we were able to reduce large positive biases that were found for the regions of Temperate North America, Central America, Europe and Southern Hemisphere South America without significant impact to other regions, improving the model performance at a regional level and better representing processes that drive fire behaviour in the Earth System.
How to cite: Teixeira, J., Burton, C., Kelley, D. I., Folberth, G., O'Connor, F. M., Betts, R., and Voulgarakis, A.: Representing socio-economic factors in INFERNO using the Human Development Index, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1671, https://doi.org/10.5194/egusphere-egu22-1671, 2022.
Fire danger rating systems (FDRS) are widely used for many purposes from planning for daily deployment of fire suppression resources to the evaluation of fire management strategies. FDRS can also be incorporated in different types of models to assess the short and long-term effects of specific fire regimes and fire management policies.
The Canadian Forest Fire Weather Index System (CFFWIS) is one of the most known FDRS’s, being extensively used for a fire early warning in several regions around the world, namely in Europe. The CFFWIS includes a set of 6 indices, based on meteorological data, which is used to predict fire weather danger and fire behavior over regions under study. To obtain a reliable assessment of the fire danger based on the CFFWIS it is crucial to determine the threshold values for each class of the CFFWIS sub-indices over different regions. One of the simplest methods to define the classes is to use percentiles based on historical data, but this method lacks information regarding wildfire history and its relation to CFFWIS sub-indices.
The proposed method is based on Fire Radiative Energy (FRE) released by fires, computed from Fire Radiative Power (FRP) product, that is generated, and disseminated in near real-time by EUMETSAT Land Surface Analysis Satellite Applications Facility. Since FRP estimates the radiative power emitted by a fire, it can be linked to fuel burned amounts and used as a proxy of fire intensity. By integrating FRP measures over a fire’s lifetime, an estimate of the total FRE released can be obtained for each event. In this work, daily FRE was derived for the 2010-2021 period, over the Mediterranean region countries. Thresholds values of each defined danger class for the FWI, FFMC, and ISI indices were obtained considering the FRE percentiles computed for different regions of the Mediterranean basin and discussed based on the different fire regimes for the region. A trend analysis of the CFFWIS sub-indices was performed to assess the fire danger behavior and the extreme fire weather over the different Mediterranean regions.
The regions where the extreme fire weather conditions have become more prevalent were identified considering the spatial correlations, and applying field significance testing allows the identification of the regions with significant trends. Since fire regimes in Southern Mediterranean countries have been changing over the last two decades, mostly due to climate-driven factors changes and to the load and structure of fuels, the observed trend towards warmer and drier conditions are expected to continue in the next years, possibly leading to an increased risk of large fires. In this context, the knowledge of fire danger trends and variability is a key factor for fire managing activities, planning and preparedness, and resources allocation.
Acknowledgments:
This study was performed within the framework of the LSA-SAF, co-funded by EUMETSAT and was partially supported by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under project FIRECAST (PCIF/GRF/0204/2017) and by the 2021 FirEUrisk project funded by European Union’s Horizon 2020 research and innovation programme under the Grant Agreement no. 101003890).
How to cite: Durao, R., Silva, M., Alonso, C., and Gouveia, C.: Calibration of the Fire Danger Classes and Trend analysis over the Mediterranean basin, based on the Canadian Forest Fire Weather Index System and the Fire Released Energy from SEVIRI/MSG. , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9651, https://doi.org/10.5194/egusphere-egu22-9651, 2022.
The Iberian Peninsula is recurrently affected by devastating wildfires that result from an interplay of human activities, landscape features, and atmospheric conditions. The fact that the Mediterranean basin, and the Iberian Peninsula in particular, is a hotspot of climate change, strongly suggests that particular attention should be devoted to the role played by atmospheric conditions on wildfire activity.
Here we present a statistical model that is able to simulate the probability of occurrence of a fire event that releases a given amount of Fire Radiative Power, provided a specified level of meteorological fire danger as rated by the Fire Weather Index.
The model combines a lognormal distribution central body with a lower and an upper tail, both consisting of Generalized Pareto (GP) distributions, and daily FWI is used as a covariate of the parameters of the lognormal and the two GP distributions.
The Iberian Peninsula is subdivided into four spatially homogeneous pyro-regions, namely the northwest(NW), southwest (SW), north (N) and east (E) regions. Fire data cover the period 2001-2020 and consist of Fire Radiative Power (FRP) as acquired by the MODIS instrument on-board Aqua and Terra Satellites. Fire Weather (FWI) data covering the same period were obtained from the Copernicus Emergency Management Service.
For each region, the statistical model is fitted to the sample of FRP of all recorded events. First a base model (with fixed parameters) is fitted to the decimal logarithm of FRP, and the quality of fit is assessed using an Anderson-Darling test. Then the model is improved using FWI as a covariate, and performances of models without and with covariate are compared by computing the Bayes Factor as well as by applying the Vuong’s closeness test.
For each region, a set of 100 synthetic time series of total annual FRP is set up using the statistical models without and with FWI as a covariate. This is achieved by randomly generating probabilities for each observed event, generating the FRP associated to that probability and then adding up the generated FRP all events for each year. The interannual variability of synthetic time series obtained is then compared with the corresponding interannual variability of the recorded events.
Results obtained for region SW show an increase from 91 to 96% of interannual explained variance of FRP when going from the model without to the model with FWI. Increases from 95 to 96%, 84 to 90% and from 78 to 86% were obtained for regions NW, N and E. It is worth stressing that these are conservative estimates of change since the dependence of number of ignitions on FWI was not taken into account.
This work was supported by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under project FIRECAST (PCIF/GRF/0204/2017).
How to cite: DaCamara, C. C., Nunes, S. A., and Pereira, J. M. C.: The role of meteorological factors on interannual variability of fire activity in Iberia: an assessment performed over four subregions, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12805, https://doi.org/10.5194/egusphere-egu22-12805, 2022.
Context
Boreal ecosystems provide numerous goods and services essential to human activities, such as wood and paper supply or the regulation of natural phenomena (floods, diseases) (Hassan et al., 2005). They also play a major role in the global climate balance, storing ~32% of the world's biogenic carbon (Pan et al., 2011; Bradshaw, 2015). Their dynamics are also intrinsically linked to fire activity, main disturbance driver in North American boreal forests (Kuuluvainen and Aakala, 2011), mainly controlled by climate-vegetation interactions (Ali et al., 2012). Under global warming, recent work predicts an increase of fire regimes, and a potential shift of the carbon sink function (Walker et al., 2019). However, Labrador and eastern Quebec regions remain poorly studied on multimillennial time scales. This study provides new insights on fire-climate-vegetation interactions in eastern Canadian forests, allowing us to better characterize the mechanisms by which climate change impacts fire regimes, and consequently forest structure and functioning.
Material and methods
To cover a wide range of fire-climate-vegetation interactions, this study is based on a North-South transect of 5 lacustrine sediment cores, covering the last 6,000 to 10,000 years across Quebec and Labrador regions. Chronologies were based on 210Pb/137Cs and 14C dating. Finally, to reconstruct local fire regimes, vegetation dynamics and climatic fluctuations during the Holocene, our study is based respectively on macrocharcoals (≥ 150 µm), pollen grains and chironomids assemblages.
Results and Discussion
Our study reveals that black spruce (Picea mariana (Mill.)) is the dominant species across the transect, but its proportion varies greatly, and is marked by a codominance with balsam fir in the south and with green alder in the north. In the south (white birch fir stand and spruce-lichen woodlands bioclimatic domains), our results show a high frequency but relatively low fire sizes during the warmest and driest periods, such as the Holocene Climate Optimum (HCO), followed by a reverse trend during the coldest and wettest periods such as the Neoglacial Period (NG), probably due to a longer fuel accumulation time promoting larger fires (Carcaillet et al., 2001). In the North (forest tundra bioclimatic domain), the HCO is marked by the absence of fire, whereas the NP is characterised by a strong increase in fire frequency, related to the progressive increase of black spruce after the deglaciation. Despite this north-south contrast, possibly related to the impact of the Atlantic Ocean, all sequences show an increase in both fire frequency and size after the industrial revolution, inducing a major change in vegetation trajectory towards more open environments marked by an increase in pioneer taxa.
Conclusion
During the Holocene, climate change induced variations in fire regimes in eastern Canada, but show spatial differences explained by black spruce dynamics and moisture inputs. Our study also reveals that temperature rises over the last 150 years have led to an increase in the frequency and size of fires and consequently to a progressive opening of the environment. This could ultimately alter the carbon sink function of boreal forests in the future (Bastianelli et al., 2017).
How to cite: Lesven, J., Druguet-Dayras, M., Millet, L., Ali, A., Bergeron, Y., Arsenault, A., Gillet, F., and Rius, D.: Global changes, fire and spruce-forest dynamics in Québec-Labrador during the Holocene., EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5199, https://doi.org/10.5194/egusphere-egu22-5199, 2022.
Fire is a pervasive component of almost every terrestrial ecosystem, but the African continent is rather unique, holding the most vulnerable ecosystems to fire which account for most of the global burned area and for more than half of fire-carbon emissions. Fire has a significant role in ecosystem functioning though our understanding of this complex process is still limited which hinders our ability to model and predict fire.
Paleofire records go beyond the short instrumental records of the last decades and can provide long-term information about fire, but only at a descriptive scale and with difficulties in relating it to the fire regime. To address these limitations, we attempt to develop a quantitative calibration model based on the examination of micro-charcoal from 137 surface sediment samples collected offshore the African continent in conjunction with a set of fire parameters (burnt perimeter, fire radiative power, fire spread) derived from satellite data, environmental information (hydrographic basins, vegetation cover, climatic parameters) and a wind dispersal particle model. Our results show that changes in charcoal concentration and morphometry are linked with fire regime and the type of burnt vegetation on the adjacent continent. In (sub)tropical settings, elongated micro-charcoal particles in high concentrations relate to rare but intense fires spreading in graminoid-mixed ecosystems whereas squared particles in low concentrations are typical for frequent but low intensity fires, characteristic for tree-dominated ecosystems.
This work provides the first calibration model of micro-charcoal in marine sediments which can be applied to long marine charcoal records to help reconstruct past fire regimes. This investigation addresses a key issue in unlocking specific methodological and theoretical problems related to fire research; it provides a better understanding of the local to regional processes that govern the fire signal and contextualize current and past environmental changes.
How to cite: Haliuc, A., Daniau, A.-L., Mouillot, F., Chen, W., David, V., Hanquiez, V., Dennielou, B., Schefuß, E., Bayon, G., and Crosta, X.: Reconstructing fire regimes using micro-charcoal in modern marine sediments off Africa, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11099, https://doi.org/10.5194/egusphere-egu22-11099, 2022.
Sedimentary charcoal records are widely used to reconstruct regional changes in fire regimes through time in the geological past. The Reading Palaeofire Database (RPD) represents the most comprehensive compilation of sedimentary charcoal data currently available. It contains 1673 individual charcoal records from 1480 sites worldwide, with sufficient metadata to allow for the appropriate selection of sites to address specific questions. Most of the records have new age models, made by re-calibrating the radiocarbon ages using INTCAL2020 and Bayesian age-modelling software. In this talk we will show how these data are being used to document changing fire regimes during the Late Quaternary and to explore how fire regimes have responded to changes in climate, vegetation and human activities. We will demonstrate the progress that has been made to calibrate the charcoal records and make quantitative estimates of fire properties. We will also explore how these data can be used to evaluate and benchmark process-based fire-enabled models. Finally, we will highlight opportunities to use the palaeo-record together with models to explore fire regimes and their consequences for land-surface processes, biogeochemical cycles and climate.
How to cite: Harrison, S., Gallagher, D., Lincoln, P., Liu, M., Shen, Y., Sweeney, L., and Villegas-Diaz, R.: Palaeofire: current status and future opportunities, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1217, https://doi.org/10.5194/egusphere-egu22-1217, 2022.
Fire-enabled vegetation models are an important component of earth system modelling. Understanding the sensitivity of vegetation and wildfire to climate change benefits from out-of-sample experiments, of which the Last Glacial Maximum (LGM; 21 ka BP) is a preferred test. Here, we compared wildfire simulations for the LGM made with four fire-enabled vegetation models using a standardized protocol and driven by a climate-model simulation of the response to known LGM changes in ice-sheet extent, atmospheric composition and insolation. We compare the resulting model output with inferred changes in fire based on charcoal records from the Reading Palaeofire Database (RPD).
All four models show a global decrease in fire at the LGM compared to the present day, consistent with the charcoal records which also record less fire. The simulated change in fire is driven principally by changes in vegetation cover at the LGM, particularly the shift from forest to more open vegetation. The simulated reduction in forest cover is consistent with pollen-based reconstructions of LGM vegetation. Despite this general agreement among models, there are differences between the simulated fire anomalies at a regional scale. The largest differences between the models occur in equatorial Africa, South America and East Asia where the amplitude and spatial extent of regions of increased fire (driven principally by the replacement of tropical trees by grassland); in some regions even the direction of change is not consistent. Comparison of the simulated changes with charcoal records from these regions identifies which model(s) perform best, but also make it clear that there is no one model that simulates observed patterns of change in fire across all of the regions.
How to cite: Lincoln, P., Harrison, S. P., Forrest, M., Kaplan, J., and Yue, C.: Evaluation of simulations of the Last Glacial Maximum with fire-enabled vegetation models from the FireMIP intercomparison project , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7457, https://doi.org/10.5194/egusphere-egu22-7457, 2022.
The Mediterranean region is strongly impacted by fires at present day. Projected warming scenarios suggest increase fire risk in the Mediterranean region (Pechony et Shindell, 2010). However, models based on modern-day statistical relationships do not consider interactions between climate, vegetation, and fire. In addition, process-based models must be tested not only against modern observations but also against climate observations different from today to cover the range of climate variability projected for the next centuries. Here, we present a new biomass burning record for the last 8,500 years in southeastern France with a mean temporal resolution of 45 years based on a marine sedimentary microcharcoal from the Gulf of Lion, located in the Rhone River prodelta. Periodicities of 500 and 1,100 years emerge from this record. Most of the peaks coincide with cold and dry periods of several century duration reflecting enhanced burning of open evergreen sclerophyllous Mediterranean forests. Among the 15 peaks of biomass burning, 7 are associated with negative North Atlantic Oscillation (NAO) phase, 8 with cold events, and 13 with low solar activity. We suggest that cold and wet conditions during negative NAO led to the accumulation of biomass while dry and cold winds during negative East Atlantic (EA) phase favored fuel flammability resulting in peaks in biomass burning. Today, large fires in southeastern France occur during negative NAO or during the Atlantic Ridge weather regime, the latter being similar to the EA (Ruffault et al. 2017). The frequency of heat-induced fire-weather favoring the largest wildfires observed in recent years in the Mediterranean region is projected to increase under global warming (Ruffault et al., 2020). Our study suggests also that the French Mediterranean region might be affected by large wind-driven fires developing in the event of negative NAO and EA modes.
References
Ruffault et al., 2017 Daily synoptic conditions associated with large fire occurrence in Mediterranean France: evidence for a wind-driven fire regime. https://doi.org/10.1007/s10584-012-0559-5
Ruffault et al., 2020. Increased likelihood of heat-induced large wildfires in the Mediterranean Basin. https://doi.org/10.1101/2020.01.09.896878
Pechony et Shindell, 2010. Driving forces of global wildfires over the past millennium and the forthcoming century. https://doi.org/10.1073/pnas.1003669107
How to cite: Genet, M., Daniau, A.-L., Bassetti, M.-A., Jalali, B., Sicre, M.-A., Azuara, J., and Berné, S.: Fire variability in the southeastern France over the past 8500 years, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8737, https://doi.org/10.5194/egusphere-egu22-8737, 2022.
Pre- and early industrial charcoal production has left a striking legacy effect on today’s soil landscapes in many forests of Central Europe and the North Eastern USA. Charcoaling in upright standing hearths (also called kilns) resulted in distinct circular micro relief structures, easily identifiable today in the field and on high resolution LiDAR-based digital elevation maps. Soils on these sites are characterized by one or multiple layers of decimetre thick charcoal rich substrate, which makes them Spolic Technosols according to the WRB soil classification. The focus of research on these sites increasingly deals with the difference of their soil physical and chemical properties in relation to unaffected forest soils and the potential implications for changes in vegetation and faunal growth. The controlling factor thereby is the soils large content of charcoal in various particle sizes, ranging from fine dust to large chunks. Studies have repeatedly shown the soils significant increase in total organic- and pyrogenic carbon content. The increase in total carbon stocks is thereby not only caused by pyrogenic carbon, but also by an apparently increased accumulation of non-pyrogenic organic matter. Here we present the latest findings regarding the carbon contents of centennially old charcoal rich technogenic substrates, sampled as part of multiple research projects in Brandenburg, Germany and the Litchfield hills in North-western Connecticut, USA. A focus will be the determination of highly aromatic carbon by the molecular marker Benzene-polycarboxylic acid (BPCA) and its prediction by FTIR-MIR chemometric methods. We discuss the results on forest soil carbon stocks on a site specific to a landscape and regional scale. Furthermore, the potential to use these sites to study the long term effects of charcoal admixture to soils by wildfires or biochar application will be discussed.
How to cite: Bonhage, A., Raab, T., Schneider, A., Raab, A., Ramezany, S., and Ouimet, W.: Pyrogenic carbon in temperate forests - long-lasting impact of historical charcoal production on soils and ecosystems, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-8312, https://doi.org/10.5194/egusphere-egu22-8312, 2022.
Mediterranean ecosystems are prone to forest fires, as evidenced by several extreme fire seasons which struck in the last two decades, including both western (2003, 2005, 2017) and eastern (2007, 2018, 2021) Mediterranean sectors. These fire seasons had a massive impact on the economy and the environment, having also caused many human casualties, including 145 in Portugal 2017 and about 100 in Greece 2018. Moreover, it is now widely accepted that these outstanding fire seasons are often associated with unusually intense droughts and heatwaves (Turco et al., 2019; Ruffault et al, 2020). Additionally, there is strong evidence that the frequency of drought events in the Mediterranean basin has increased significantly in the last decades and is bound to increase further under different climate change scenarios (Tramblay et al., 2020).
The relentless tendency for increasing summer temperatures in Europe in recent decades, when compared to the last 500 hundred years, also underlines that the increment in temperatures is extensive to central and Scandinavian countries (Sousa et al., 2020), where forest fires have become considerably more frequent. Recent assessments have emphasised the synergy between drought and extremely hot summers in the Mediterranean (Russo et al., 2020).
In addition to this climate change scenarios point to a likely increase in the frequency of two specific heat-induced fire-weather types, precisely those that have been related to the largest wildfires observed in recent years (Ruffault et al., 2020). Heat-induced fire-weather types are characterized by compound dry and warm conditions occurring during summer heatwaves, either under moderate (heatwave type) or intense (hot drought type) drought. The frequency of heat-induced fire-weather is projected to increase by 14% by the end of the century (2071-2100) under the RCP4.5 scenario, and by 30% under the RCP8.5. In summary, these results consistently suggest that the frequency and extent of wildfires will increase throughout the Mediterranean Basin.
Ruffault J., Curt T., Moron V., Trigo R.M., Mouillot F., Koutsias N., Pimont F., Martin-StPaul N., Barbero R., Dupuy J.-L., Russo A., Belhadj-Khedher C., (2020) Scientific Reports, 10, 13790, doi: 10.1038/s41598-020-70069-z
Russo A., Gouveia C.M., Dutra E., Soares P.M.M., Trigo R.M. (2019) Environmental Research Letters, 14(1), 014011, doi: 10.1088/1748-9326/aaf09e
Sousa P., Barriopedro D., García-Herrera R., Ordoñez C., Soares P.MM, Trigo R.M. (2020) Communications Earth & Environment, 1, 48, doi: 10.1038/s43247-020-00048-9
Turco M., Jerez S., Augusto S., Tarín-Carrasco P., Ratola N., Jimenez-Guerrero P., Trigo, R.M. (2019) Scientific Reports, 9, 1, doi: 10.1038/s41598-019-50281-2
This work was supported by national funds through FCT (Fundação para a Ciência e a Tecnologia, Portugal) under project FIRECAST (PCIF/GRF/0204/2017). M.T. is supported by the Spanish Ministry of Science, Innovation and Universities - Spanish State Research Agency and the European Regional Development Fund through the PREDFIRE projects (RTI2018-099711-J-I00, MCI/AEI/FEDER, EU) and the Ramón y Cajal grant (RYC2019-027115-I). S.J. thanks the Spanish Ministry of Science, Innovation and Universities - Agencia Estatal de Investigación and the European Regional Development Fund for the support received through the EASE project (RTI2018 100870 A I00).
How to cite: Trigo, R., Turco, M., Jerez, S., Sousa, P., Russo, A., and Ruffault, J.: Recent and future intense fire seasons in the Mediterranean basin: the increasing role of droughts and heatwaves, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1169, https://doi.org/10.5194/egusphere-egu22-1169, 2022.
More intense fire seasons have been favoured by climate changes worldwide, like Russia, Brazil, the USA, Canada and Portugal. Portugal experienced numerous severe fire seasons with catastrophic wildfires that caused enormous impacts in the last years. This study aimed to investigate the fire risk evolution in Portugal over the last 40 years and the extreme wildfire emission impacts derived from remote sensing data. First, the Fire Weather Index (FWI) from 1979 to 2020, at 0.25º spatial resolution, provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA5 reanalysis version 4 based on meteorological variables, was used. Then, FWI monthly mean values and trends were analysed for four districts of Southern Portugal (Beja, Evora, Faro and Portalegre). The results indicate that the Faro district presented extreme fire risk values, which peaked on August 2, 2018, one day before the Monchique (a mountain in Faro) wildfire began and lasted between August 3 and 10. The Monchique wildfire was the most destructive in Portugal during 2018, with almost 27.000 ha burned. Second, based on the previous results, atmospheric products derived from the TROPOspheric Monitoring Instrument (TROPOMI) aboard the Sentinel-5 Precursor satellite, the first Copernicus mission dedicated to atmospheric composition monitoring, were collected. These datasets were obtained from Google Earth Engine (GEE), the online platform that combines multiple imageries and datasets with cloud processing to perform analyses. The Carbon monoxide (CO) and Nitrogen dioxide (NO2) concentrations, as well as Absorbing Aerosol Index (AAI) products were analysed during the fire event. The concentrations released by the wildfire reached values 3 and 5 times higher than usual for CO and NO2, respectively. Therefore, the work confirms that extreme wildfire events can release huge pollutant concentrations into the atmosphere. Also, the Sentinel-5 products are useful to evaluate the fire emission evolution in extreme wildfires events and may constitute additional valuable information to combine with ground-based information to map air quality related to wildfire occurrences.
This research was funded by the European Union through the European Regional Development Fund in the framework of the Interreg V A Spain - Portugal program (POCTEP) through the CILIFO project (Ref.: 0753-CILIFO-5-E), FIREPOCTEP project (0756-FIREPOCTEP-6-E), and also by national funds through FCT - Foundation for Science and Technology, I.P. under the PyroC.pt project (Refs. PCIF/MPG/0175/2019), ICT project (Refs. UIDB/04683/2020 and UIDP/04683/2020), and TOMAQAPA (PTDC/CTAMET/ 29678/2017).
How to cite: Santos, F. L., Couto, F. T., Salgueiro, V., Potes, M., Costa, M. J., Bortoli, D., and Salgado, R.: Fire weather risk analysis over Portugal in the last decades and their impacts over the atmosphere - The Monchique study case, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11616, https://doi.org/10.5194/egusphere-egu22-11616, 2022.
Toward the development of the 5th generation of the Global Fire Emission Database (GFED5), we provide evidence for a significantly higher level of contemporary global fire emissions than what has been reported in previous inventories, as a result of advances in our understanding of burned area, fuel consumption, and emission factors. Increases in the availability of high-resolution burned area datasets from Sentinel and Landsat now allow for more effective estimation of fire scars associated with small and discontinuous fires in many biomes. By combining these regional-scale datasets with burned area and active fire observations from MODIS, we estimate that global burned area exceeded 700 Mha per year during 2001-2020. This estimate is more than 40% higher than previous estimates from GFED4 with small fires (GFED4s), mostly as a consequence of increases in savanna and grassland burning across Africa, South America, and Southeast Asia. At the same time, more extensive field observations in boreal forest ecosystems provide evidence for higher levels of fuel consumption than has been integrated into previous regional and global inventories. New emission factor observations from tropical peatlands and boreal forests provide evidence for a stronger smoldering phase of emissions, elevating emissions of carbon monoxide and organic carbon aerosol. Together, these advances suggest the impact of contemporary wildfires may have been underestimated in past work; we conclude by exploring the compatibility of this inventory with atmospheric aerosol and trace gas observations using a global atmospheric chemistry model.
How to cite: Randerson, J., Chen, Y., Xu, L., Hall, J., Giglio, L., van Wees, D., Veraverbeke, S., van der Werf, G., Morton, D., Wiggins, E., Andela, N., and Hantson, S.: Evidence for a stronger global impact of fire on atmospheric composition, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12015, https://doi.org/10.5194/egusphere-egu22-12015, 2022.
Complex interactions between climate and land-use are altering the course of the fire regimes across the tropics. In Brazil, many recent peaks of burned area have co-occurred with extreme climate events, high deforestation rates and agricultural expansion. Particularly during compound dry and hot years, widespread fires have become increasingly common, and an intensification of the fire activity due to climate change may be already underway.
Based on a compound-event-oriented framework to assess fire risk, we provide evidence on the extent to which fire activity and the associated impacts could be constrained if anthropogenic global warming is limited. Here we quantify the nonlinear relationships between compound climate drivers and burned area across two main Brazilian biocultural heritage sites (Xingu and Pantanal) and estimate compound-event-related fire risks in terms of the occurrences of compound drivers beyond which the fire response becomes extreme.
Our results show that the exponential response of burned area to climate is well explained by compound events characterized by air dryness and precipitation deficits (high VPD and low precipitation) and that climate-change induced fire risks will increase due to the co-occurrence of drier and warmer climatic conditions under global warming. However, if global warming is constrained to +1.5°C instead of +3°C, the likelihood of fire risk can be reduced by ~11% in the case of the most prominent fire types (forest fires in Xingu and grassland fires in the Pantanal). We thus conclude that if we slow down the rate of warming and follow more sustainable uses of land, we might be able to prevent the crossing of tipping points and the consequent downward spiral of socio-environmental impacts that threatens these regions.
How to cite: Ribeiro, A. F. S., Brando, P. M., Santos, L., Rattis, L., Hirschi, M., Hauser, M., Seneviratne, S. I., and Zscheischler, J.: Present and future tropical fire risks associated with compound events, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2611, https://doi.org/10.5194/egusphere-egu22-2611, 2022.
In the future, large wildfires are expected to become more frequent and intense. Not only do they pose a serious threat to people and ecosystems, but they also affect the Earth's atmosphere. Aerosols from large wildfires can even reach the stratosphere where they can linger for months to years. However, little is known about their impact on climate. In particular, the potential of large wildfires to cause temperature changes in the stratosphere has hardly been studied.
In our study, we analyze two extreme wildfire events, those in 2017 in North America and those in 2019/20 in Australia, using new satellite observational data. We find strong effects of the fires on the atmospheric temperature structure and short-term climate in the stratosphere. The results show significant warming of the lower stratosphere by up to 10 K within the aerosol clouds emitted by the wildfires immediately after their formation. The climate signal in the lower stratosphere persists for several months, reaching 1 K for the 2017 North American wildfires and a remarkable 3.5 K for the 2019/20 Australian wildfires. This is stronger than any signal from volcanic eruptions in the past two decades. Such extreme events potentially influence the atmospheric composition and stratospheric temperature trends, underscoring their importance for future climate.
Improved knowledge of the temperature signals from extreme wildfires is particularly important for trend analysis. Our ongoing research on this topic aims to further improve the separation of natural variability from anthropogenic influences in climate trend detection, especially in the stratosphere.
How to cite: Stocker, M., Ladstädter, F., and Steiner, A. K.: Observing the climate impact of large wildfires on stratospheric temperature, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10524, https://doi.org/10.5194/egusphere-egu22-10524, 2022.
Located right in the middle of the tropical warm pool, convective activities over Southeast Asia are subject to interannual variability in sea surface temperature due primarily to varying phases of the El Niño-Southern Oscillation (ENSO). Observations often show a reduction in the amount of rainfall during El Niño and its increase during La Niña over Southeast Asia. Because of this interannual variability in rainfall and humidity, emissions of aerosol particles and their abundance in the atmosphere, often manifested in aerosol optical depths, are also subject to interannual variability; they increase during El Niño and are reduced during La Niña on average. Our previous study has shown an impact of biomass-burning aerosols on convective clouds, which enhanced rainfall and generally invigorated convection. Here we present the comparison of this aerosol effect among different years with different ENSO phases. We utilized month-long cloud-resolving simulations by the WRF-CHEM model that are capable of including both aerosol direct and indirect effects. The extensive simulation domain size and time period enabled the inclusion of a wide range of contributors to cloud development over the area, from aerosol activation to ENSO-affected meteorology. We show whether the invigoration effect that we found from the year of strong El Niño in 2015 still holds in years of weaker El Niño or even during La Niña.
How to cite: Takeishi, A. and Wang, C.: Impacts of Fires on Convective Cloud Features in Southeast Asia: Variability with ENSO, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10391, https://doi.org/10.5194/egusphere-egu22-10391, 2022.
Boreal forest fires are increasing in frequency and intensity due to climate change. Yet there is little knowledge on the impacts of fire severity and post-fire management decisions on the regeneration and carbon balance of production forests in Eurasia. To investigate these issues, we established 6 sites in a Swedish Pinus sylvestris forest that burned in 2018. Specifically, we evaluated the effects of (i) fire severity (low severity ground fire vs high severity stand-replacing canopy fire), (ii) post-fire wood management (salvage-logged vs unlogged) and (iii) post-fire vegetation management (natural regeneration, seeding or planting nursery seedlings of P. sylvestris). At each site, we measured soil respiration (CO2 release to the atmosphere) and methane fluxes (soil CH4 uptake) using the manual chamber approach, soil microclimate and vegetation cover for the first 3 years after the fire (2019-2021). Two of the sites also have eddy covariance flux measurements, which provided an insight into the ecosystem-scale carbon balance.
Fire severity had a strong impact on forest soils, with high fire severity sites having lower soil respiration, warmer soils and less vegetation regrowth compared to a low fire severity site. Surprisingly, soil respiration was similar at a low fire severity site and unburnt site, despite the almost complete loss of the soil organic layer during the ground fire. There were no clear effects of fire or post-fire management on the soil methane fluxes. Salvage-logging of a high fire severity site had no additional effects on soil respiration compared to leaving the dead trees standing. Salvage-logging of a low fire severity site led to a decline in soil respiration, but turned the ecosystem into a net source of CO2 due to the removal of the living trees. In terms of P. sylvestris regeneration, our results showed that the seedling density following natural regeneration was similar to or higher than the seedling density in sites which had been manually seeded or replanted with nursery seedlings.
Our results suggest that post-fire management interventions may not facilitate faster vegetation regrowth and the recovery of carbon uptake by forests compared to natural regeneration in the immediate post-fire years. Furthermore, despite the start of new vegetation growth and declines in soil CO2 release, the high fire severity and/or salvage-logged sites remain net CO2 sources 3 years after the fire, which must be considered in estimations of the net effect of fires on Sweden’s forest carbon balance.
How to cite: Kelly, J., Doerr, S. H., Ekroos, J., Ibáñez, T. S., Santín, C., Soares, M., and Kljun, N.: Evaluating the effects of fire severity and post-fire management decisions on the carbon balance of a Swedish forest, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7318, https://doi.org/10.5194/egusphere-egu22-7318, 2022.
Fire derived pyrogenic organic matter / charcoal is a source of environmentally persistent free radicals, which are precursors of potentially harmful reactive oxygen species. We analyzed charcoal samples from ten wildfires, including crown as well as surface fires in boreal, temperate, subtropical and tropical climate regions. Concentrations of environmentally persistent free radicals in these samples were orders of magnitude higher than those found in soils or other “background” matrices, as measured via electron spin resonance spectroscopy. The highest concentrations were measured in woody charcoals that were highly carbonized. We also found that environmentally persistent free radicals remained unexpectedly stable in the field for at least 5 years.
More details can be found in our recently published article: https://www.nature.com/articles/s43247-021-00138-2
How to cite: Sigmund, G., Santin Nuno, C., Pignitter, M., Tepe, N., Doerr, S. H., and Hofmann, T.: High concentrations of environmentally persistent free radicals in fire derived pyrogenic organic matter, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3357, https://doi.org/10.5194/egusphere-egu22-3357, 2022.
Fire is a major disturbance in natural ecosystems and more extreme fires are predicted to occur in the future. Plant species can survive or resist wildfires and adapt to fire-prone regimes by exhibiting fire-related plant traits such as serotiny and heat-simulated germination. Resprouting is one of the most common plant traits that confer resilience to fire, promoting rapid post-fire recovery and affecting ecosystem dynamics. We investigated the relationships between the abundance of resprouting woody species, fire return interval and fire intensity in three regions: Europe, Australia and South and Central America. Species abundance data were obtained from the SplotOpen database while resprouting information are derived from regional and global databases, field information and the literature. Fire return time and fire intensity at each site were estimated using remotely sensed observations (MODIS MCD64CMQ, MODIS MCD14ML and Fire Atlas). We show that the abundance of resprouting woody species decreases with increasing fire return interval but that resprouters are most abundant at intermediate levels of fire intensity. These patterns are seen in all the three regions. Given that the abundance of resprouting woody species is strongly related to the fire regime, it should be possible to model their distribution in an optimality framework. Since the abundance of resprouters will affect ecosystem post-fire recovery, it is important to include this trait in fire-enabled vegetation models in order to simulate ecosystem dynamics adequately.
How to cite: Shen, Y., Prentice, C., and Harrison, S.: Investigating woody species resprouting in response to fire, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1007, https://doi.org/10.5194/egusphere-egu22-1007, 2022.
Recently identified post-fire carbon fluxes indicate that in order to understand if global fires represent a net carbon source or sink, one must consider both terrestrial carbon retention through pyrogenic carbon (PyC) production, and carbon losses via multiple pathways. Here, these legacy source and sink pathways are quantified using a CMIP6 land surface model to estimate Earth's fire carbon budget. Over 1901-2010, global PyC drives annual soil carbon accumulation of 337 TgCyr-1, offset by legacy carbon losses totalling -248 TgCyr-1. The residual of these values constrains maximum annual pyrogenic carbon mineralisation to 89 TgCyr-1, and PyC mean residence time to 5387 years, assuming steady state. However, paucity of observational constraints for representing PyC mineralisation mean that without assuming steady state, we are unable to determine the sign of the overall fire carbon balance.
The residual is negative over forests and positive over grassland-savannahs (implying a potential sink), suggesting contrasting roles of vegetation in the fire carbon cycle. Without widespread tropical grassland-savannah coverage, the legacy effects of fires could not feasibly enhance terrestrial C storage -a result afforded by grasses’ capacity for fire recovery. The dependency of the fire C residual on vegetation composition suggests that the preservation/restoration of native grasslands may be an important vector for decreasing C losses from future fire activity. We call for significant investments in understanding of PyC degradation and its drivers, in addition to improved estimates of legacy fire C fluxes. Reliable quantification of PyC mineralisation and erosion, particularly over grasslands, remains the principal missing link in a holistic understanding of fire’s role in the Earth system.
How to cite: Bowring, S. P. K., Jones, M. W., Ciais, P., Guenet, B., and Abiven, S.: Pyrogenic carbon decomposition critical to resolving fire's role in the Earth system, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1372, https://doi.org/10.5194/egusphere-egu22-1372, 2022.
Climate change has several impacts on our Earth. Even though wildfires are natural processes to sustain structure of an ecosystem, there is a significant increase in the global fire cases and their extent in the recent years caused by the climate change. These wildfires have important impacts on air quality, climate and relatedly public health. Copernicus Atmospheric Monitoring Service (CAMS) indicated that Siberia, North America, and the Mediterranean regions are greatly impacted by wildfires and the intensities of these fires are expressed as Fire Radiative Power (FRP). Effect of wildfires can also be observed with gas pollutant satellite retrievals of CO, NO2, and HCHO which is an important volatile organic carbon (VOC).
Turkey was challenged with wildfires that result in the destruction of forests, the death of animals and devastating impacts on local people in 2021. CAMS Global Fire Assimilation System (GFAS) indicated that the worst fire case observed in Turkey compared with other Mediterranean countries. Global Forest Watch fire counts showed that, fire counts reached up to 695 and 385 in summer (between June-August) 2021 for Antalya and Mugla provinces, respectively. However, fire counts did not exceed 165 fires in the summer season for either Antalya or Mugla in the last five years. Moreover, there was a significant increase in fires in the forested lands for Mersin province as well. Fire counts reached up to 171 per day (31st August) in Antalya province and fire smokes were observable from MODIS Corrected Reflectance images in the fire period. In addition, air pollutants caused by these fires were observable with high resolution TROPOMI retrievals.
In this study, multi-pollutant satellite retrievals were used to investigate the wildfires air quality impacts on the Southwestern Turkey. VIIRS S-NPP Fire Radiative Power product and TROPOMI CO, NO2, and HCHO, products were used to analyze impacts of these extreme wildfire cases. Products were processed spatially and temporally for two months (July-August 2021). A specific attention was given on period of 28th July-12th August. A 1×1 km2 gridded domain covering the impacted region was selected to investigate the spatial distribution of these pollutants. 29th and 31st of July were the days where the impacts of wildfires were analyzed specifically. Wind speed and direction were used to understand the relation between meteorological conditions and the pollution distribution caused by the wildfires. Aerosol signals will be also investigated using MODIS aerosol optical depth (AOD) and TROPOMI aerosol index (AI) retrievals.
How to cite: Eke, M., Cingiroglu, F., and Kaynak, B.: Impacts of summer 2021 wildfire events in Southwestern Turkey on air quality with multi-pollutant satellite retrievals, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12134, https://doi.org/10.5194/egusphere-egu22-12134, 2022.
Wildfires on permafrost covered with the boreal forest can influence vegetation composition, surface soil moisture, and the active layer. Since wildfires on permafrost occur extensively in unpredictable areas, remote sensing is a useful tool for monitoring burn severity and ecosystem changes. Optical spectral indices such as the differenced normalized burn ratio (dNBR) and normalized difference vegetation index (NDVI) were traditionally used to detect burn severity and vegetation regrowth. However, since optical imagery is significantly affected by cloud cover and weather conditions, there is a limitation in acquiring temporally dense images. Synthetic Aperture Radar (SAR) can obtain images regardless of day/night or weather conditions, so it is possible to densely observe the area of interest spatiotemporally. In addition, SAR images, unlike optical images, can acquire information on the active layer of the permafrost in the winter season. This study aimed to analyze winter season time-series SAR backscattering coefficient change with burn severity in south Northwest Territories, Canada using optical and SAR data. The study area, south Northwest Territories, belongs to the discontinuous permafrost zone and consisted of the taiga. Burn severity and vegetation regrowth were estimated by dNBR and NDVI using optical imagery. To increase the temporal resolution, Landsat-8 OLI and Sentinel-2 MSI were acquired through the cloud-based Google Earth Engine (GEE) in the summer season. C-band dual-polarization Sentinel-1 and X-band single-polarization TerraSAR-X were obtained to understand the multi-frequency backscattering coefficient to fire-induced changes. The changes pattern of the SAR backscattering coefficient varies according to the burn severity, especially in the winter season, not affected by vegetation and soil moisture. It can be seen that the wildfires affected the changes in the scattering mechanism in permafrost on the boreal forests. These results represent that C-band and X-band SAR images have the potential to monitor the changes of the active layer with burn severity.
How to cite: Lee, Y., Oh, J., Kim, S. Y., Jung, Y. T., and Park, S.-E.: Spatiotemporal post-fire change analysis using optical and SAR imagery, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12301, https://doi.org/10.5194/egusphere-egu22-12301, 2022.
Fire is naturally an integral part of the northern boreal forests dynamics. However, anthropogenic activity has greatly affected the fire history in Fennoscandia, especially during the last millennia and the effective fire suppression practically led to the absence of a natural fire regime in boreal forests in Finland. However, the changing climate conditions may increase the risk of severe fire events regardless of the fire management. Therefore, it is important to look into the long-term interactions between human impact, fire and vegetation succession in order to understand the possible future role of fire in boreal forests.
One of the oldest protected areas in Europe is located in Central Finland and provides a good opportunity to investigate the change from natural fire and vegetation dynamics to human controlled fire regime and the natural vegetation succession after cessation of the slash-and-burn cultivation. The site is known to have been under slash-and-burn cultivation until the beginning of the 19th century and the last known burnings were done in the 1840s after which the site has been left to natural succession. The site was partly protected in 1911 and it was included into national the old-growth forest reserve protection program in 1994.
In order to investigate the long-term natural fire history and the role of human impact in the fire and the vegetation dynamics during last 3000 years we collected peat cores covering from two small forest hollows from the Kuusmäki old-growth forests protected area. Macroscopic (> 150 µm) charcoal and Neurospora-fungal spores are used to reconstruct the fire history and pollen analysis is performed to reconstruct the long-term vegetation dynamics in the study area.
The preliminary results demonstrate an increase in charcoal abundance from 16th century suggesting increased fire activity and a more intensive period of slash and burn cultivation in the area until the beginning of the 19th century. The absence of charcoal during the last century suggests absence of fire after the cessation of slash and burn cultivation. These results together with the vegetation succession will be further discussed in the presentation.
How to cite: Kuosmanen, N., Aakala, T., and Seppä, H.: Role of human impact on fire history and vegetation succession in one of the oldest protected forests in Europe, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2463, https://doi.org/10.5194/egusphere-egu22-2463, 2022.
Recent years have seen unprecedented fire activity at Arctic latitudes, leading to severe consequences including unhealthy air quality in high latitude towns and cities. While wildfire occurrence and severity result from a complex interplay between natural and anthropogenic factors, weather is a key factor.
Weather conditions that promote high wildfire risk are characterized by the combination of high temperatures, little precipitation and low humidity, and often high winds. All of these can be affected by human-induced climate change and evidence is emerging that wildfire risk is already increasing in many regions. Such changes not only manifest as shifts in the means and extremes of the weather variables but can also be changes in the shape of their distributions. The importance of the full, regional Probability Density Functions (PDFs) of individual and aggregated variables, which contain information on expected weather not apparent from the distribution mean or tails, but through changes to their overall shape, for understanding climate risk has been broadly discussed in the literature. Furthermore, while simulations with regional climate models to derive such information are costly and time consuming, the advent of large ensembles of coupled climate model simulations has recently opened new opportunities.
Here we present a detailed characterization of the distribution and variability of weather variables conducive to wildfire risk across five high-latitude boreal regions in North America, Scandinavia and Russia. Building on methodology developed in Samset et al. (2019), we quantify the PDFs of daily data for a broad set of individual variables, as well as for the aggregate change expressed using the Canadian Fire Weather Index. Using ensembles of coupled simulations from two climate models (CanESM5 and MPI-ESM1-2) and two CMIP6 scenarios (the Shared Socioeconomic Pathways SSP1-2.6 and SSP5-8.5), we consistently quantify the changes of regionally and seasonally resolved PDFs under different levels of global warming.
Our results provide a comprehensive picture of the potential future changes in drivers of fire weather and wildfire risk in the pan-Arctic region and demonstrate the difference between regions. We also show how statistical descriptions combined with emulation of Earth System Model (ESM) information can offer an alternative pathway to resource demanding model runs, for rapidly translating science to user-oriented information.
How to cite: Lund, M. T., Nordling, K., Gjelsvik, A. B., and Samset, B. H.: Projected changes in variability of fire weather in boreal regions under different levels of global warming, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3871, https://doi.org/10.5194/egusphere-egu22-3871, 2022.
Unprecedented wildfires swept Mediterranean Europe in the summer of 2021 wreaking havoc economically and socially while clearing large swaths of forest land. Those that scorched the southern coastal highlands in Turkey came on the heels of a heat wave and at the peak of the arid season. Nearly two thirds of the Anatolian Peninsula are under the influence of Mediterranean-type climate and prone to seasonal wildfires, a quality that also encourages high species diversity. The region’s heterogenous topography is home to different meso- and micro-climates which in turn translate into high rates of endemism. Although fire as disturbance is essential for the regeneration of Mediterranean-type ecosystems, potential changes in fire frequency and severity, coupled with longer periods of drought expectations - mainly as a result of anthropogenic deforestation and climate change - is duly raising concerns. The expected increase in the frequency and intensity of climate-based disturbances necessitates some form of a predictive mechanism for future protection and mitigation, especially for these otherwise fire-adapted ecosystems. Dynamic Global Vegetation Models (DGVMs) with built in disturbance schemes when forced with future projections of climate models can be powerful tools in this regard.
In this study, we present our preliminary findings from six different model simulations, run with LPJ-GUESS, a process based DGVM. We initially introduced three native conifer species with different fire histories and significant distributions in the Anatolian Peninsula to the model and forced it with climatic drivers from ERA5 Land reanalysis dataset for the historical period. Once confident that our simulation results closely reflected the historical fires in the remote sensing datasets available through Google Earth Engine, we continued to force the model with climatic drivers from different model contributions to CMIP6, bias-corrected, interpolated to the 9-km horizontal resolution of ERA5 Land reanalysis and reflecting the RCP 8.5 scenario. All simulation results were analyzed using Climate Data Operators (CDO), ArcGIS, and R computing language.
Our preliminary results indicate an overall increase in pyro-diversity for the country across all simulations. A potential expansion of wildfire range towards the northwest was also observed, a curious outcome as this region includes the western Black Sea mountain ranges that are known for high precipitation rates. These mountains are also home to a rich forest cover with a fine mixture of broadleaved and conifer species spreading horizontally along different altitudinal belts. In light of our preliminary findings and along with our continuing research on the effects of any potential future climate-change related shifts in the fire regime on forest composition, we urge additional study of different landscape scale disturbances (i.e. soil erosion and landslides) which may potentially be triggered as a result of a diversifying and intensifying fire regime and which may have a significant impact for the terrestrial ecosystems and livelihood.
This study benefited from the 2232 International Fellowship for Outstanding Researchers Program of the Scientific and Technological Research Council of Turkey (TUBITAK) grant 118C329. The financial support received from TUBITAK doesn’t mean that the content of the publication is scientifically approved by TUBITAK.
How to cite: Ekberzade, B., Yetemen, O., and Sen, O. L.: Looking into a fuzzy future: coupled effect of pyrogeography and a changing climate on an already fragile terrestrial ecosystem , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-239, https://doi.org/10.5194/egusphere-egu22-239, 2022.
Understanding the response of fire to climate variations is essential to adapt fire management systems under climate change. Although several studies have analysed the drivers of the average spatial variability of fire, the assessment of the temporal variability of fire in response to climate across the globe has proved challenging, largely due to complexity of the processes involved, the limitation of observation data and the compound effect of the multiple drivers, which usually cause non-linear effects.
In this study, we analyse how much of the interannual variability in observed burned area (BA) is linked with temporal variations in climate at global scale. To solve this question, we use the burned area data of the FireCCI51. product for the period 2001-2019 at the global scale, and different climate metrics that are directly related to drought occurrence, including indices like the Fire Weather Index (FWI), the Standardized Precipitation Evapotranspiration Index (SPEI), and the Standardized Precipitation Index (SPI). Our study shows complex spatial patterns in the relationship between climate drivers and BA variability, highlighting where variations in FWI, SPI, SPEI or their interaction explain BA variability. While in some areas the interannual variability of burned area does not show a statistically significant influence of climate variability, over a substantial portion of the global burnable area (~60%) the BA variability can be explained by interannual variability of climate drivers. Globally, climate variability accounts for roughly two thirds (64%) of the observed temporal BA variability.
How to cite: Gincheva, A., Jerez, S., Pausas, J. G., Bedía, J., Vicente-Serrano, S. M., Provenzale, A., Chuvieco, E., Abatzoglou, J., and Turco, M.: Climatic drivers explain the interannual variability of the global burned area, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11760, https://doi.org/10.5194/egusphere-egu22-11760, 2022.
Deep pyroconvection can strongly modify surface weather conditions, especially when a firestorm develops, completely altering fire spread and making it more difficult to predict and control. However, the limited number of observations constrains our understanding of this type of events, so the environmental controls on deep pyroconvection are not entirely clear and, in particular, there are still uncertainties about the atmospheric conditions conducive to the development of this phenomenon. We conduct idealised numerical simulations with the fire-atmosphere coupled model WRF-Fire initialised with selected real-case atmospheric profiles of wind, temperature and moisture, obtained from the ERA5 database, corresponding to the 100 days of highest fire risk per year during the 2010-2019 period at six different European fire-prone locations. For each of these atmospheric profiles, we perform a suite of paired experiments of an ideal fire spreading through five different fuel categories. Each pair consists of a control run with interaction between fire and atmosphere and a simulation in which the sensible and latent heat fluxes from the fire are turned off (uncoupled simulation). This experiment allows us to make a significant statistical study of pyroconvection events and thus analyse which environmental factors favour its development. We found that a high fuel load, a large vertical temperature lapse rate between the 850 hPa and the 500 hPa levels and a high moisture content in the lower layers of the atmosphere are some of the main factors in the development of firestorms.
How to cite: Senande-Rivera, M., Insua-Costa, D., and Míguez-Macho, G.: Analysis of the environmental conditions favoring the development of deep pyroconvection in Southern Europe , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-11856, https://doi.org/10.5194/egusphere-egu22-11856, 2022.
Pantanal saw a catastrophic fire season in 2020, with a quarter of the biome hit by flames (around 4 million ha). Protected and indigenous areas burnt entirely, and it is estimated that at least 17 million vertebrates died, including several endangered species endemic to the biome. These dramatic events drew attention to the occurrence and aftermath of fire within a fire-sensitive ecosystem such as Pantanal’s wetlands.
The RPPN (Reserva Particular do Patrimônio Natural) SESC Pantanal was one of such protected areas severely affected in 2020, with around 2/3 of its territory burnt. Here, we analyse the historical fire behaviour within the RPPN, including the 2020 events, using remote sensing products over the 2001-2020 period.
Although fire has historically occurred within the RPPN at an average of 2 400 ha burned per year, the 2020 fire events were an absolute outlier with more than 70 600 ha burned. Before 2020, only 2010 reached above 10 000 ha of burned areas, and the most extreme events were found to be those above 3 000 ha. When considering the 2001-2019 period, wetlands and grasslands are the land cover types that burn the most (52 and 17% of the total burned area, respectively), followed by forests and savanna formations (16 and 9%, respectively). The year of 2020, however, changed this pattern: most burned areas occurred in forested areas (40%), followed by grasslands (26%) and savanna formations (24%). We also found that fire is not recurrent: during the 19 years of historical data the vast majority of burned areas occurred only once (60%), 35% burned up twice or thrice, and solely 5% burned more than 3 times.
Future climate change assessments seem to point at a warmer and drier future for the biome, when events such as 2020 might become more regular. Our results provide an historical characterization leading up to the 2020 fires within the RPPN SESC Pantanal, that may be of use for fire managers in light of future climate change.
How to cite: Silva, P. S., Nogueira, J., and Libonati, R.: Pantanal’s 2020 fire season in perspective: the case of a natural heritage reserve, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-384, https://doi.org/10.5194/egusphere-egu22-384, 2022.
Biochar has become an accepted soil amendment due to its potential to improve soil properties and as a tool to increase carbon sequestration. The latter is based on its relatively high biochemical recalcitrance augmenting the slow C pool after its addition to soils. However, newer studies indicated that the longevity of biochar and naturally produced pyrogenic organic matter (PyOM) in soils is lower than commonly assumed. Many of those studies are based on the determination of CO2 production changes or on the recovery of their isotopic labels in the soil after amendment of biochar or PyC incorporation. Most probably because of the lack of appropriate techniques to differentiate between the natural soil organic matter fraction and the added black carbon, only few reports are available which relate turn-over data with chemical alterations of biochar during aging or the impact of the latter on the quality of the total SOM pool. In order to fill this gap, we applied virtual fractionation of SOM into different organic matter pools by different solid-state NMR techniques. Whereas the most common combines the determination of turnover rates via stable isotope techniques, an alternative approach takes advantage of different relaxation behavior of biochar and humified SOM. In both cases spectra can be calculated that show either the added biochar or the respective SOM. In the frame of the present work, the concept and the potential of the two approaches will be explained by using examples studied in our laboratory. With this, we intend to provide a further powerful tool which can lead to a better understanding of the biochemistry related to the transformation of PyC and biochar during aging and their subsequent integration into the soil organic matter fraction.
Acknowledgement: Financial support has been provided by the European Institute of Innovation and Technology (EIT), a body of the European Union, under Horizon2020, the EU Framework Programme for Research and Innovation (Project 21217 Black to the future - biochar and compost as soil amendment)
How to cite: Knicker, H., Knicker, M., García de Castro Barragán, J. M., and Velasco-Molina, M.: NMR-spectroscopic virtual fractionation of soils mixed with pyrogenic carbon as a tool to separate chemical processes related to aging of pyrogenic carbon from those occurring during humification of soil organic matter , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-2603, https://doi.org/10.5194/egusphere-egu22-2603, 2022.
Intensifying wildfires in high-latitude forest and tundra ecosystems are a major source of greenhouse gas emissions, releasing carbon through direct combustion and long-term degradation of permafrost soils and peatlands. Several remotely sensed burned area and active fire products have been developed, yet these do not provide information about the ignitions, growth and size of individual fires. Such object-based fire data is urgently needed to disentangle different anthropogenic and bioclimatic drivers of fire ignition and spread. This knowledge is required to better understand contemporary arctic-boreal fire regimes and to constrain models that predict changes in future arctic-boreal fire regimes.
Here, we developed an object-based fire tracking system to map the evolution of arctic-boreal fires at a sub-daily scale. Our approach harnesses the improved spatial resolution of 375m Visible Infrared Imaging Radiometer Suite (VIIRS) active fire detections. The arctic-boreal fire atlas includes ignitions and daily perimeters of individual fires between 2012 and 2021, and may be complemented in the future with information on waterbodies, unburned islands, fuel types and fire severity within fire perimeters.
How to cite: Scholten, R., Chen, Y., Randerson, J., and Veraverbeke, S.: Development of an arctic-boreal fire atlas using Visible Infrared Imaging Radiometer Suite active fire data, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4922, https://doi.org/10.5194/egusphere-egu22-4922, 2022.
Fire modelling incorporated into global dynamic vegetation models (DGVMs) allows for the projection of changes to fire-related biogeophysical and biogechemical processes under future climate scenarios, including anthropogenic climate change. Due to the large grid sizes often required to efficiently model fire and vegetation dynamics in a global manner, fire-enabled DGVMs generally neglect some finer-scale effects, including slope. However, slope can have a significant impact on the spread of individual fires and, therefore, the global area burned. As a fire moves uphill, the angle of flames is better suited to heating nearby fuel, thus increasing the rate of spread relative to fires on level ground. In this study, we apply a function to account for the impact of slope on fire spread in the SPITFIRE model incorporated into the LPJmL5.3 DGVM to improve the calculation of fire-related processes, including burnt area. We aggregate slope data across a grid cell to account for the impact of slope in a general way appropriate to the grid size used in SPITFIRE. Our approach, while focused on the SPITFIRE model, may also be applicable to other DGVM-based fire models.
How to cite: Oberhagemann, L., Drueke, M., Billing, M., von Bloh, W., Sakschewski, B., Rust, H., and Thonicke, K.: Accounting for the impact of slope on fire spread in a dynamic global vegetation model, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5320, https://doi.org/10.5194/egusphere-egu22-5320, 2022.
Wildfires are one of the major disturbances in the global terrestrial ecosystems and can be the key driver for both vegetation composition and structure, affecting the carbon stocks above and below the surface. With a total of about 2 Pg(C)/year emitted into the atmosphere wildfires also play an important role in the global carbon cycle. Beyond this, emissions from wildfires influence regional air quality, can have a fertilizing effect on the surroundings, or alter the albedo of both the burned area itself but also of distant areas when e.g. black carbon is deposited on ice sheets or snow. Large fires creating pyrocumulonimbus-clouds even elevate trace gases into the lower stratosphere.
The chemical and physical evolution of the compounds emitted by wildfires can be simulated by modern CTMs (Chemistry Transport Models) and ESMs (Earth-System Models). A key uncertainty in these models, though, are the fires and the resulting emissions themselves, both in space and amount. Many plume rise models use satellite retrievals for fire intensity as e.g. FRP (Fire Radiative Power) and top height for hindcast or historical simulations, where the accuracy of FRP is anti-correlated with the total emissions because the plume itself blocks the frequencies needed to measure a fire’s intensity, i.e. the larger in scale a fire is the less accurate its intensity, and therefore, it is difficult to generate a vertical emission profile. Furthermore, for future projections, these parameters need to be computed from available information within the operating model.
The approach presented here was developed in the framework of the project CoBACCA and is an attempt to invert this problem. Therefore, we use the 2nd generation dynamic global vegetation model LPJ-GUESS and its incorporated wildfire-model SIMFIRE-BLAZE. Vegetation in LPJ-GUESS is represented by 12 different Plant Functional Types (PFTs; 10 tree and 2 grass PFTs) plus litter and soil pools. In combination with meteorological parameters, the combustion model BLAZE then computes their mortality, their combustion completeness, the intensity of the fire, and finally a vertical emission profile.
Another critical issue for the use of vertical emissions is that one of the uncertainties in atmospheric models is the height of the planetary boundary layer (PBL) which more or less determines whether emitted air-parcels remain in the mixing layer or reach the free troposphere or even the lower stratosphere. We, therefore, decided to compute the vertical emission profile relative to a model-generated PBL.
These emission profiles will be used online in the upcoming version 4 of the ESM EC-Earth but they can also be used offline as emission inventories for other models. This is a step towards a fully coupled plume-rise sub-grid model to be developed within EC-Earth4.
How to cite: Nieradzik, L. and Bergman, T.: A novel parameterization for wildfire plumes in LPJ-GUESS, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-12049, https://doi.org/10.5194/egusphere-egu22-12049, 2022.
