AS3.5
Orals: Wed, 26 Apr | Room 0.11/12
It is vital and informative to understand the lifetime and timescales of tropospheric O3 so that we can predict the impact of changing O3 sources on its abundance throughout the troposphere, and thence its climate and pollution damage. As an example, current model intercomparison projects (MIPs) diagnose the impact of stratosphere-troposphere exchange (STE) flux of O3 into the troposphere by assuming that loss of this added O3 occurs through 3 specific reactions (O(1D)+H2O, HO2+O3, OH+O3) and is linear in O3, and that production through XO2+NO reactions is a constant. A linearization of the full chemistry with respect to O3 clearly shows these assumptions are wrong (see ATom data, shown here). Another example is the effort made to define odd-oxygen by a chemical family grouping (e.g., O3+O+NO2+…) to better understand the timescales for O3 loss, yet the true pattern of the odd-oxygen family should be apparent from the eigenvectors of the system.
Here we define and test a new protocol for model experiments designed to understand how the coupling of O3 with the full chemistry can change the accumulation and the pattern of decay depending on the O3 source (stratosphere, surface pollution, aviation). We take a full chemistry-transport model (UCI CTM) and generate a control run for the present day, then add direct O3 emissions (not in the control run) from (i) a large industrial region, (ii) aviation, and (iii) the mid-latitude tropopause where most STE occurs. These perturbation runs produce a seasonally varying additional O3 burden – which gives us the seasonally varying lifetime for such sources – and then we cut emissions and watch the decay pattern in terms of e-fold timescale and patterns of key species to derive the odd-oxygen family pattern. Due to the large latitudinal and seasonal variation in reactivity rates (see ATom data: Guo et al. ACP, 23, 99–117, 2023), we expect lifetimes and timescale to vary with location and timing of O3 emissions.
How to cite: Prather, M. and Zhu, X.: Lifetimes and timescales of tropospheric ozone , EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-9839, https://doi.org/10.5194/egusphere-egu23-9839, 2023.
Long-term exposure to ambient ozone is linked with respiratory-related mortality, while the emerging climate change is projected to pose double-edged challenges for ozone air quality. Here, we calculate the impact of emissions- and climate-change under SSP3-7.0 scenario on ozone-related mortality on a global scale, using historical (experiment histSST) and future simulations (experiments ssp370SST and ssp370pdSST) from three CMIP6 Earth System Models (ESMs) (GFDL-ESM4, EC-Earth3-AerChem, and UKESM1-0-LL). The ssp370SST experiment follows time-varying SSTs, while the SSP370pdSST follows a present-day climatology for SSTs. The chronic obstructive pulmonary disease mortality attributable to ozone pollution is estimated following the Global Burden Disease (GBD) 2019 approach, by using the ozone season daily maximum 8-hour mixing ratio (OSDMA8), the baseline mortality rate (from the GBD), and the SSP3-7.0 present and future gridded population. An increase in ozone-related mortality of approximately 2.5 million people per year globally is projected at the end of the century (2090) with respect to 2000 due to emissions and population changes. The climate-change footprint on ozone-related mortality exhibits large variability among the ESMs; yet, over India and China all ESMs project an increase of ozone-related mortality in the future, highlighting the importance of the ozone penalty due to global warming in regions with strong anthropogenic sources.
How to cite: Akritidis, D., Bacer, S., Zanis, P., Georgoulias, A. K., Horowitz, L. W., Naik, V., O'Connor, F. M., Keeble, J., Le Sager, P., van Noije, T., Zhou, P., and Pozzer, A.: Future projection of ozone-related mortality under SSP3-7.0 scenario based on CMIP6 simulations , EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-5642, https://doi.org/10.5194/egusphere-egu23-5642, 2023.
Near-term climate forcers (NTCF) are a group of chemically and radiatively active constituents that have a relatively short lifetime in the atmosphere (<20 years). They can exert effects on the climate, important for the future rate of climate warming, and in elevated concentrations at the lowest most levels of the atmosphere can lead to poor air quality and detrimental impacts on human health. Two important NTCFs that are considered in this study are tropospheric O3 and fine particulate matter (with a diameter less than 2.5 microns – PM2.5). Future climate mitigation scenarios that seek to limit future temperature increases, and include reductions in air pollutant emissions, need to consider the impact on climate, air quality and human health from changes in NTCFs. Here we use results from UKESM1 (an Earth system model with interactive chemistry and aerosols) in different future sensitivity scenarios that consider air pollutant emission mitigation, future climate change and land-use change, conducted as part of the Aerosol and Chemistry Model Intercomparison Project (AerChemMIP). We assess the impact on climate (in terms of effective radiative forcing), air pollutants (in terms of change in ambient surface concentrations) and human health (in terms of long-term adult mortality from exposure to ambient air pollutants) by comparing the results from these sensitivity scenarios to the future reference scenario ssp370, a scenario that involves low mitigation of climate and air pollutants.
Scenarios that involve combined strong mitigation of aerosols and O3 precursors, including large reductions in global CH4 concentrations, produce the largest benefits to climate (an ERF of -1.2 Wm-2), air quality (10-25% reduction in O3 and PM2.5 concentrations) and human health (>25% reduction in the rate of long-term premature mortality). Benefits to health are largest across Asia for these scenarios (a 44% reduction in the mortality rate). If global CH4 concentrations are not reduced or aerosol precursors emissions are reduced in isolation, then there is a detrimental impact to future climate but there are still improvements to future air quality and a reduction in the long-term air pollutant health burden. If climate and air quality mitigation measures are not enacted on top of ssp370 then there is a penalty to global climate, a detrimental impact on air pollutant concentrations and an increase in the long-term air pollutant health burden across certain regions (e.g. by 20% over Africa). Considering only the impacts from climate change show increases in air pollutant concentrations over some continental regions and also an increase in the long-term rate of premature mortality by more than 10% over Europe and parts of Asia, offsetting some of the benefits achieved from emission mitigation measures. Quantifying co-benefits and trade-offs between climate, air quality, and human health together in this way, enables policy makers to understand the outcomes of different mitigation strategies and to identify pathways with maximum benefits across all three axes.
How to cite: Turnock, S., Reddington, C., and O'Connor, F.: The Climate, Air Quality and Health co-benefits and trade-offs from different future mitigation scenarios involving Near-Term Climate Forcers in UKESM1, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-2685, https://doi.org/10.5194/egusphere-egu23-2685, 2023.
Air quality co-benefits are expected to occur with greater climate mitigation, however climate mitigation is not expected to occur in isolation of other socio-economic changes. Although modelling studies investigating these co-benefits are common, limited work uses the recently developed “Shared Socioeconomic Pathways” which factor in the different patterns of climate mitigation, socioeconomic development and pollution control. Additionally, as the SSPs were designed for climate model ensembles, such as CMIP6, existing work usually uses global climate or earth system models with interactive chemistry simulated at relatively coarse horizontal resolution. These computational trade-offs may impact how effectively they model air quality at human exposure-relevant scales and may miss differing trends seen only at subregional scales.
We have used the anthropogenic emissions inputs from different SSPs which have different mitigation patterns applied to climate change and air pollution in 2050 to drive a specialised Atmospheric Chemistry model (WRF-Chemv4.2) at 30km resolution over Europe. We compare these to a 2014 control simulation. We present the validation of this model setup, which suggests an overestimation of surface PM2.5 concentrations, largely driven by overestimated NO3 aerosol, but good agreement with O3 observations. We find that while significant potential for air quality co-benefits exists, these effects are non-linear, with both PM2.5 and O3 worsening in some locations and scenarios despite increased pollution control compared to the present. We also find notable spatial heterogeneity in the change of PM2.5 and O3 across Europe in some scenarios. Overall, however the results show that across Europe, scenarios with greater mitigation of climate change and air pollution show improvements in air quality that could lead to benefits to human health.
How to cite: Clayton, C. J., McQuaid, J. B., Marsh, D. R., Turnock, S. T., Graham, A. M., Pringle, K. J., and Kumar, R.: High Resolution Simulations of European Air Quality in 2050 Following Different CMIP6 Climate Change Mitigation Pathways , EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-4217, https://doi.org/10.5194/egusphere-egu23-4217, 2023.
Methane plays a central role in the atmosphere, affecting the atmospheric oxidising capacity through its reaction with OH, air quality through its role as an ozone precursor, and climate through its greenhouse gas properties.
Methane emissions-driven models provide an opportunity to study the Earth system within a global model that features the most accurate representation of the methane cycle. Here we use the methane emissions-driven configuration of the UK Earth System Model, UKESM1-CH4.
Previously we explored a zero anthropogenic methane scenario, which focused on attributing the composition, air quality and climate impacts of future anthropogenic methane emissions. Here, we study the potential co-benefits of methane mitigation: reducing NOx and CO emissions. We use SSP1-2.6 emissions pathways for CO and NO in these scenarios.
The complex interactions between methane, CO, OH and NOx are represented more completely in the emissions-driven model. We calculate the sensitivity of ozone and OH to the CO and NO emissions changes, and their dependence on the methane burden. We also show the impacts on other near-term climate forcers such as aerosols and ozone.
Global reductions in CO and NO emissions have disproportionate effects in different regions. We present analysis of the regional differences in ozone and OH response, based on the HTAP regions. We demonstrate much greater effects in South and East Asia than in the Europe and North America.
How to cite: Staniaszek, Z., Griffiths, P. T., Folberth, G. A., O'Connor, F. M., and Archibald, A. T.: Regional impacts of CO and NOx mitigation in a methane emissions-driven model, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-1291, https://doi.org/10.5194/egusphere-egu23-1291, 2023.
Reforestation is widely proposed for carbon dioxide (CO2) removal but the impact on climate, via atmospheric composition and surface albedo changes, remains relatively unexplored. Using two Earth System models, UKESM1 and CESM2, we compare scenarios where existing forests expand to a near biophysical limit (with croplands fixed at 2015 to preserve food production) with SSP1-2.6 and SSP3-7.0 at 2050 and 2095.
In the reforestation scenario, global BVOC emissions are 18% (35%) higher than SSP3-7.0 at 2050 (2095) and 8% (12%) higher than SSP1-2.6. The resulting increases to secondary organic aerosols and aerosol scattering, from BVOC emission changes, drive a negative radiative forcing (RF). However, this is outweighed by the positive RF from increases to methane and ozone and decreases to surface albedo.
The net RF is equivalent to CO2 increases of 13 (32) ppm relative to SSP3-7.0 at 2050 (2095) and 3 (8) ppm relative to SSP1-2.6. These indirect factors offset ~25% of the additional CO2 removal arising from reforestation relative to SSP3-7.0 and ~10% relative to SSP1-2.6. This highlights the importance of assessing the full response of the Earth System to reforestation, rather than just the potential CO2 removal.
How to cite: Weber, J., King, J. A., Abraham, N. L., Grosvenor, D. P., Beerling, D. J., Lawrence, P., and Val Martin, M.: Chemistry-albedo feedbacks from reforestation partially offset CO2 removal benefits, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8236, https://doi.org/10.5194/egusphere-egu23-8236, 2023.
Water vapor plays an important role in many aspects of the climate system, by affecting radiation, cloud formation, atmospheric chemistry and dynamics. Even the low stratospheric water vapor content provides an important climate feedback, but current climate models show a substantial moist bias in the lowermost stratosphere. Here we report crucial sensitivity of the atmospheric circulation in the stratosphere and troposphere to the abundance of water vapor in the lowermost stratosphere. We show from a mechanistic climate model experiment and inter-model variability that lowermost stratospheric water vapor decreases local temperatures, and thereby causes an upward and poleward shift of subtropical jets, a strengthening of the stratospheric circulation, a poleward shift of the tropospheric eddy-driven jet and regional climate impacts. The mechanistic model experiment in combination with atmospheric observations further shows that the prevailing moist bias in current models is likely caused by the transport scheme, and can be alleviated by employing a less diffusive Lagrangian scheme. The related effects on atmospheric circulation are of similar magnitude as climate change effects. Hence, lowermost stratospheric water vapor exerts a first order effect on atmospheric circulation and improving its representation in models offers promising prospects for future research.
How to cite: Charlesworth, E., Plöger, F., Birner, T., Baikhadzhaev, R., Abalos, M., Abraham, L., Akiyoshi, H., Bekki, S., Dennison, F., Jöckel, P., Keeble, J., Kinnison, D., Morgenstern, O., Plummer, D., Rozanov, E., Strode, S., Zeng, G., and Riese, M.: Stratospheric water vapor affecting atmospheric circulation, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-14506, https://doi.org/10.5194/egusphere-egu23-14506, 2023.
The ICOsahedral Non-hydrostatic (ICON) modelling system was originally developed by DWD and MPI-M for a range of weather (forecast) and climate applications. An Aerosols and Reactive Tracers (ART) module was added by KIT to enable a comprehensive assessment of composition interactions within the atmospheric domain. Recognising that atmospheric processes happen on a multitude of temporal and spatial scales, flexible horizontal and vertical grid options are a key element of versatile model configurations in use. Here, we present a selection of results from different ICON-ART configurations that explore (stratospheric) ozone-climate interactions and stratosphere-troposphere coupling – e.g. regional climatic impacts of the ozone hole (and ozone losses in other regions) and global warming induced changes in jet-streams – in different types of integrations. In addition, we explore the potential to forecast “chemical weather” with ICON-ART, including environmental (UV) indices.
Starting with time-slice experiments, we provide a range of examples using the ICON-ART modelling system to investigate (idealised) climate change scenarios with respect to different threshold temperatures (reached under global warming) and the climatic impact of the ozone hole (and ozone losses in other regions). For the latter, halogen induced depletion of (stratospheric) ozone can be switched on and off in our modelling world. We illustrate how such integrations allow the unambiguous attribution of certain climate change effects, e.g. the contribution of the ozone hole (and other regional ozone losses) to regional surface warming in Antarctica and changes to regional and global “effective radiative forcing”, and the change of jet stream variability under global warming. Moving on, we explore the capability of ICON-ART to work with regionally nested grids to capture accurately smaller spatial scales and to provide “meaningful” forecasts of environmental (UV) indices, thus, demonstrating comprehensively the seamless philosophy regarding processes, scales and applications with the flexible ICON-ART modelling system.
How to cite: Braesicke, P., Hanft, V., Kusakova, K., Ruhnke, R., Satitkovitchai, K., Sinnhuber, B.-M., Versick, S., and Weimer, M.: Beyond ozone hole impacts: Seamless composition-climate interactions explored with ICON-ART, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8610, https://doi.org/10.5194/egusphere-egu23-8610, 2023.
Orals: Thu, 27 Apr | Room 0.11/12
The Asian summer monsoons are globally significant meteorological features, creating a strongly seasonal pattern of precipitation, with the majority of the annual precipitation falling between June and September. The stability of such a strongly seasonal hydrological cycle is of extreme importance for a vast range of ecosystems and for the livelihoods of a large share of the world’s population.
Simulations are performed with an intermediate complexity climate model, PLASIM, in order to assess the future response of the Asian monsoons to changing concentrations of aerosols and greenhouse gases. The radiative forcing associated with aerosol loading consists of a mid-tropospheric warming and a compensating surface cooling, which is applied to India, Southeast Asia and East China, both concurrently and independently. The primary effect of increased aerosol loading is a decrease in summer precipitation in the vicinity of the applied forcing, although the regional responses vary significantly. The decrease in precipitation is only partially ascribable to a decrease in the precipitable water, and instead derives from a reduction of the precipitation efficiency, due to changes in the stratification of the atmosphere.
When the aerosol loading is added in all regions simultaneously, precipitation in East China is most strongly affected, with a quite distinct transition to a low precipitation regime as the radiative forcing increases beyond 60 W/m2. The response is less abrupt as we move westward, with precipitation in South India being least affected. By applying the aerosol loading to each region individually, we are able to explain the mechanism behind the lower sensitivity observed in India, and attribute it to aerosol forcing over East China. Additionally, we note that the effect on precipitation is approximately linear with the forcing.
The impact of doubling carbon dioxide levels is to increase precipitation over the region, whilst simultaneously weakening the circulation. When the carbon dioxide and aerosol forcings are applied at the same time, the carbon dioxide forcing partially offsets the surface cooling and reduction in precipitation associated with the aerosol response.
How to cite: Reccchia, L. and Lucarini, V.: Modelling the effect of aerosol and greenhouse gas forcing on the Asian monsoons with an intermediate complexity climate model, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-3339, https://doi.org/10.5194/egusphere-egu23-3339, 2023.
Aerosol emissions have a wide range of impacts on the climate both near to and far from emission sources. Impacts span from local changes in surface solar warming to large-scale modifications of atmospheric circulation patterns and monsoonal precipitation. They have also been found to have an outsized near-term influence on extreme events in recent climate model studies. Consequently, future aerosol emission changes are likely to contribute to climate related risk in many highly populated regions, some of which are particularly vulnerable, for instance, to shifts in precipitation patterns or timing with respect to growing seasons. However, aerosol climate impacts generally follow patterns and time evolutions that are markedly different to those from greenhouse gas driven global surface warming, and our understanding of them is still plagued by high scientific uncertainty.
Given the urgent need for improved knowledge about the near-term influences of changes in aerosol emissions, we here introduce SyRAP-FORTE – a tool for understanding and decomposing the local and remote climate effects of regional aerosol emissions. SyRAP – a set of Systematic Regional Aerosol Perturbations – is developed using FORTE2.0, a Reduced Complexity (RC) climate model developed in the UK. Current and expected future aerosol emission changes are particularly strong in East and South Asia, where high population densities imply high potential climate risk. In the initial version of SyRAP, presented here, we therefore perturb absorbing and scattering aerosols, separately, over India and East China, to assess their separate influence on local responses in a range of climate parameters.
We document and validate the climate responses in FORTE to the regional aerosol perturbations, showing for instance that removing emissions of absorbing aerosols over both East China and will cause a local drying, but a range of more widespread effects. We find that SyRAP is able to reproduce the overall aerosol responses documented in the literature, and also that it allows us to decompose the influences of different aerosol species from the two regions on the climate near to, and far from, the emission sources.
Finally, we show how SyRAP can be used as input to emulators and tunable simple climate models, and as a ready-made tool for projecting the effects of near-term changes in Asian aerosol emissions.
How to cite: Stjern, C. W., Samset, B. H., Wilcox, L., and Joshi, M.: Climate influences of Asian anthropogenic aerosols decomposed using a Reduced Complexity Model, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-7319, https://doi.org/10.5194/egusphere-egu23-7319, 2023.
After years of rapid growth, India has become a hotspot for emissions of aerosols and their precursors, recently surpassing China in terms of magnitude of SO2 emissions. The resulting high air pollution levels influence climate through interactions with solar radiation, clouds, and the hydrological cycle, and pose one of the greatest environmental threats to public health. Model estimates of these impacts are influenced by the substantial spread that exists between current emission inventories, in terms of both trend and magnitude. Activity and fuel data is heterogeneous and can be challenging to compile, and many emission sources are highly region specific. Hence, inventories need to be based on up-to-date national statistics and detailed sectoral information.
Here we use one such inventory for Indian anthropogenic emissions, the recently developed, bottom up SNEII (Sabe National Emission Inventory for India) dataset to simulate and evaluate regional air pollution levels for 2018. SNEII includes a more detailed spatial allocation of point sources of emissions and sectoral disaggregation than many global inventories. The results are compared to estimates using the Community Emission Data System (CEDS) emissions, version 2021, also placing them in the context of the trend over the past decades. For most species, SNEII estimates higher emissions, and we explore the resulting impact of these differences on simulated aerosol abundances, as well as implications for radiative forcing and premature mortality. Finally, we quantify the sectoral contribution to air pollution with a finer breakdown than previously provided, including sectors unique for Indian/South Asian region.
How to cite: Lund, M. T., Sahu, S. K., Mangaraj, P., Samset, B. H., Chowdhury, S., Myhre, G., and Johansen, A. N.: Quantifying effects of Indian aerosol emissions on regional aerosol abundances, energy balance, and health impacts, using a novel national emission inventory, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-1597, https://doi.org/10.5194/egusphere-egu23-1597, 2023.
This study investigates the effect of aerosol changes on regional climate in East Asia. Especially, we focus on the recent decreasing trend of aerosol concentrations in China from 2011 to 2018. We conduct climate sensitivity simulations using the Community Earth System Model (CESM) atmospheric general circulation model (AGCM) with observed monthly sea surface temperatures (SST) and sea ice concentrations (SIC) and coupled general circulation model (CGCM) with its own predicted SST and SIC from the coupled ocean and sea ice models. We prescribe the observed monthly aerosol optical depths from the Moderate Resolution Imaging Spectroradiometer (MODIS) onboard Terra and Aqua satellite for the base simulations and period-averaged monthly aerosol optical depths for the sensitivity simulations. Comparisons of 50 ensemble averages between the base and sensitivity simulations for the AGCM and CGCM models show that the decreasing aerosols in East Asia warm up the region due to increased net shortwave radiation. We also found that the CGCM simulations show much stronger and more extensive warming in East Asia due to decreasing aerosols than the AGCM simulations, implying the importance of the aerosol-ocean-atmosphere feedback.
How to cite: Lee, S., Park, R., Yeh, S.-W., and Jeong, Y.-C.: Effect of aerosol changes on regional climate in East Asia, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-10054, https://doi.org/10.5194/egusphere-egu23-10054, 2023.
The world has changed: You can feel it in the air as temperatures rise, you can feel it in the water as precipitation patterns change. Much of what has once been our daily weather is lost. It began with humankind emitting greenhouse gases and aerosols. However, there is a growing resistance that wants to limit theses emissions.
Daily variability can be described by probability density functions (PDF). Change can manifest as changes of the mean properties of weather-related variables, and/or changes in the chape of their PDFs. In this study, we examine how regional PDF shapes change due to increasing temperature, driven primarily by greenhouse gas emissions, and due to emissions of different aerosols species (black carbon and sulfate). Our main questions are: (1) How do shapes of regional daily PDFs evolve with global warming? (2) How do these changes differ in response to aerosol and greenhouse gas emissions? (3) And which aerosol-related teleconnections induce these changes in PDF shapes? As changes in shape affect low and high extremes differently, we aim to link changes in PDF shape to changes in extreme events of daily temperature and precipitation by using parameters describing PDF width and asymmetry.
We use data from PDRMIP single forcer climate model simulations to examine how changes in regional and global aerosol concentrations change the PDF shapes. We also use three CMIP6 large ensembles (MPI-ESM1-2-LR, CanESM5 and ACCESS-ESM1-5) to examine changes in PDF shape at five different levels of global warming, from 1°C to 4 °C. Our main questions are how the shapes of regional daily PDFs evolve with globalwarming, how their changes differ between aerosol and greenhouse gas induced changes, and what teleconnections due to regional aerosol changes induce in PDF shapes.
For the time will soon come when aerosols will shape the near future of our weather.
How to cite: Nordling, K., Samset, B., and Fahrenbach, N.: Change in daily weather variability due to warming and regional aerosols., EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-1836, https://doi.org/10.5194/egusphere-egu23-1836, 2023.
The presence of a short-lived climate pollutant, PM2.5, can influence the condition of air quality in specific regions. In the atmosphere, the PM2.5 concentration pattern might be affected by climate phenomena, such as El Niño Southern Oscillation (ENSO). In this study, we examined the ENSO (El Niño and La Niña) feedback on PM2.5 concentration in Indonesia by using an hourly reanalysis dataset from CAMS global emission inventories during the period 2004 - 2021. We analyzed the spatial anomaly of PM2.5 concentrations by calculating the difference between each El Niño/La Niña in three stages; Moderate, Strong, and Very Strong episodes with the Normal condition. Results show that PM2.5 conditions in Indonesia during ENSO revealed different responses in each region. ENSO had positive feedback to most of the western and central parts of Indonesia, especially the islands of Sumatra and Kalimantan. This positive feedback on PM2.5 generally occurred in forest fire prone areas. Those areas were sensitive to El Niño episodes which caused the prolonged droughts associated with suppressed rainfall to enhance the risk of forest fires occurring, resulting in elevated PM2.5 concentrations emitted from burned materials. Meanwhile, several areas in central Java, western Java, and Nusa Tenggara showed a weak negative effect. Other areas in eastern Indonesia generally showed no feedback or ENSO events did not have a significant effect on PM2.5 concentrations.
How to cite: Nahas, A., Sopaheluwakan, A., Putri, A. S., Kinanti, N. P., Taryono, T., and Setiawan, B.: ENSO Feedback Mechanism on PM2.5 Concentration in Indonesia, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-4781, https://doi.org/10.5194/egusphere-egu23-4781, 2023.
Black carbon (BC) aerosols absorb solar radiation and thus heat the atmosphere. This process occurs on a short time scale and can influence clouds, precipitation, and boundary layer meteorology. Global climate models (GCMs) strongly disagree in their representation of such rapid adjustments, adding to the uncertainty in the effective radiative forcing (ERF) due to BC. Disagreements are at least partly caused by differences in parametrization of the highly regional and potentially non-linear rapid adjustments, which are poorly resolved in coarse resolution GCMs. Knowledge of how the rapid adjustments depend on model resolution is therefore important.
Here we explore the dependence of rapid adjustments on model resolution by performing a set of idealized experiments using a GCM, the Community Earth System Model version 2 (CESM2) with fixed sea-surface temperatures, downscaled by a regional climate model, the Weather Research and Forecasting (WRF), for five years at 45 km horizontal resolution over East and South Asia and at 15 km resolution covering East China. To ensure a sufficient climate response in the models, we perturb BC emissions by a factor of ten, and compare the results to separate simulations with a fivefold increase in (scattering) sulfate emissions and a doubling of CO2 concentrations.
Preliminary results indicate similar BC-induced responses between CESM2 and 15 km WRF simulations in terms of tropospheric temperature and humidity, and mean precipitation, but strong dependence on model and/or resolution in the cloud response to BC. Potential differences in seasonal and extreme precipitation will be examined, and we plan to explore finer scales using the WRF model in Large Eddy Simulation (LES) mode down to 100 m horizontal resolution.
How to cite: Hodnebrog, Ø., Stjern, C. W., and Myhre, G.: Aerosol-radiation interactions on global to local scales, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-13213, https://doi.org/10.5194/egusphere-egu23-13213, 2023.
The role of marine phytoplankton emissions in aerosol-cloud interactions is still a cause of large uncertainties in climate modelling. We investigate the effects of DMS and sea spray aerosol, which are both affected by marine phytoplankton, on the droplet concentrations of liquid clouds. To do this we examine MODIS satellite data for an area of liquid clouds in the Southern Ocean during the southern hemispheric summer. Backwards trajectories of air masses from the clouds were simulated with the FLEXPART Lagrangian particle dispersion model for a duration of 9 days.
Clouds whose trajectories were not influenced by continental air masses could be split into two groups based on their trajectory history in the two days before encountering cloud: group 1 spent most of their time in the free troposphere, whereas group 2 spent their last two days within the boundary layer.
Group 1 cloud droplet concentrations were positively correlated with exposure to sea surface chlorophyll that took place prior to them entering the free troposphere (i.e., at least 2 days before encountering their clouds), whereas droplet concentrations were negatively correlated with wind speed in the last day before encountering clouds. Group 2 clouds did not show the same correlations. Instead, wind speeds in the last two days before a cloud encounter were positively correlated with cloud droplet number concentration, with the relationship between the two having a steeper slope for higher chlorophyll values.
These results give an insight into the factors controlling the changes in Southern Ocean cloud properties with associated climate impacts via cloud brightening effects.
How to cite: Kovacs, E., Grosvenor, D., Carslaw, K., Mulcahy, J., and Lachlan-Cope, T.: Effects of marine biology and air-mass trajectories on cloud brightness, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-5883, https://doi.org/10.5194/egusphere-egu23-5883, 2023.
Over Fennoscandian mountain birch forest region, there are increased attacks of geometrid moth larvae. These herbivores can change forests from a carbon sink to a carbon source. When moths start to chew on leaves, large quantities of biogenic volatile organic compounds (BVOCs) are released. Herbivory-induced BVOC emissions have been observed and quantified at a few sites over Fennoscandian mountain birch forest, but we know very little of their potential regional implications for atmospheric processes.
In this work, we extracted birch defoliation information based on MODIS leaf area index (LAI) for an outbreak year 2012, and together with field-observed relationship between leaf defoliated level and changes in emissions, we modelled herbivory-induced BVOC emissions at regional scale using MEGAN. Taking a step further, we fed MEGAN-modelled BVOC emission data with or without considering herbivory impacts to a two-way coupled WRF-CMAQ system to dynamically assess the impacts of these emissions on the atmospheric chemistry and climate system .
During the whole growing season of 2012, the defoliation at some MODIS grids can be as high as 90%, and the large defoliation mainly occurs in June and July. For t-β-ocimene, Other Monoterpenes, Stress and Other compound groups, herbivory contributes to more than 30, 8, 5 and 16 times the increase in the seasonal sum for the defoliated regions. For terpenes, herbivory increased monthly emissions up to 3 times for June and July. The reduction of emissions caused by herbivory-caused decrease in LAI is much smaller than the herbivory-induced increase. We also found strong impacts of herbivory-induced BVOC emissions on downward shortwave radiation and cloud radiative forcing.
This is the first time we can link all these components, i.e., satellite monitoring of leaf defoliation, in-situ observation, ecosystem and atmospheric modelling together to answer the research questions related to the regional importance of insect herbivory on atmospheric composition and climate.
How to cite: Tang, J., Wang, H., Cai, Z., Guenther, A., Rinnan, R., Olsson, P.-O., Borchmann, R. L., Davie-Martin, C. L., Schurgers, G., Ren, Z., Rieksta, J., and Li, T.: Insect herbivory have significantly altered BVOC emissions, SOA concentration and radiative forcing over Fennoscandian birch forest, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-12434, https://doi.org/10.5194/egusphere-egu23-12434, 2023.
Posters on site: Thu, 27 Apr, 16:15–18:00 | Hall X5
On March 10th 2020, COVID-19 was categorised as a global pandemic by the World Health Organisation (WHO), concerned both by the alarming levels of spread and severity across 114 countries. On account of this, India announced the first nationwide lockdown on 25th March 2020. The present study examines the impact of the lockdown period on the atmospheric levels of overall aerosols (PM2.5) and on individual aerosol species (Black Carbon (BC), Organic Matter (OM), Sulphate (SO42-), Nitrate (NO3-) and Ammonium (NH4+) over the Indian subcontinent using a chemical transport model, CHIMERE. In this study, CHIMERE is forced externally by Weather Research and Forecasting (WRF) model as a meteorological driver in offline mode. The model was run for usual and pandemic lockdown scenarios to estimate the reductions in aerosol species concentration during the lockdown period. The cessation of industrial and transportation activity caused a significant drop in PM2.5 concentration of 20–30% over India, and notably 48% over Delhi. In-land regions saw a sharp decline in PM2.5 concentration (39–48% at Delhi, Bengaluru, and Raipur) compared to coastal locations (11–24% decrease at Kolkata, Mumbai, Chennai, Ahmedabad, and Bhubaneswar), which is explained by the marine influence at those coastal locations. The decrease in measured PM2.5 concentration is very well reproduced by the model for the agricultural state of Telangana, where agricultural residue burning is prominent as a major source of anthropogenic emissions. The elimination of traffic and industrial emissions during the lockdown period resulted in a significant decrease of aerosol species concentration (BC (10-40%), OM (3-10%), SO42- (30-80%), NO3- (70-90%) and NH4+ (60-80%)) over the subcontinent. The study also aims to understand the effect of lockdown on the aerosol optical property and found a reduction of 10-40% in the aerosol optical depth (AOD) over the Indian region. The reductions in the simulated mass concentration of PM2.5 are in eminent agreement (bias ≤ 40%) with the available measurements, rendering the model to be effective for simulating low emission scenarios over India.
How to cite: Dubey, K. and Verma, Dr. S.: Ambient aerosol variation in India during the COVID-19 lockdown : Simulations from high resolution chemical transport model (CHIMERE), EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-91, https://doi.org/10.5194/egusphere-egu23-91, 2023.
Methane (CH4), the second most important greenhouse gas directly emitted by human activity, is removed from the atmosphere via chemical degradation.
In this study we assess the radiative feedback from atmospheric CH4 resulting from changes in its chemical sink, which is mainly the oxidation with the hydroxyl radical (OH) and, which is influenced by temperature and the chemical composition of the atmosphere.
We present results from numerical simulations with the chemistry-climate model EMAC perturbed by either CO2 or CH4 increase.
The essential innovation in the simulation set-up is the use of CH4 emission fluxes instead of prescribed CH4 concentrations at the lower boundary. This means that changes in the chemical sink can feed back on the atmospheric CH4 concentration without constraints.
For both forcing agents, CO2 and CH4, we explore so called rapid radiative adjustments in simulations with prescribed sea surface temperatures, as well as slow radiative feedbacks and the climate sensitivity in respective simulations using an interactive oceanic mixed layer.
To quantify individual physical and chemical radiative adjustments and feedbacks we use the partial radiative perturbation method in offline simulations with a radiative transfer model consistent with the one used in the online simulations.
First results show a negative feedback of atmospheric CH4 in a warming and moistening troposphere. As water vapour is a precursor of OH, increased humidity leads to increasing OH mixing ratios. This leads in turn to a shortening of the CH4 lifetime and a reduction of the CH4 mixing ratios accordingly. This decrease in CH4 also affects the response of tropospheric ozone (O3) leading to a less pronounced increase of O3 in the tropical upper troposphere compared to previous studies of the O3 response following a CO2 perturbation (Dietmüller et al., 2014;Nowack et al., 2015;Marsh et al., 2016).
How to cite: Stecher, L., Winterstein, F., Dameris, M., Jöckel, P., and Ponater, M.: Estimating the impact of the radiative feedback from atmospheric methane on climate sensitivity, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-6263, https://doi.org/10.5194/egusphere-egu23-6263, 2023.
Despite methane’s importance as a greenhouse gas, the Earth System Models that contributed to Phase 6 of the Coupled Model Intercomparison Project (CMIP6) typically prescribe surface methane concentrations - following either historical observations or specified future shared socioeconomic pathways. Here, we make use of novel methane emissions-driven capability in the UK’s Earth System Model to explore the role of an interactive methane cycle, including wetland emissions, on the model’s equilibrium climate sensitivity and its transient climate response to changes in carbon dioxide concentration.
The climate response to external forcings is strongly influenced by climate feedbacks and with the inclusion of interactive methane in Earth System Models, it becomes important to understand the effects of changing carbon dioxide and meteorology on wetland emissions. This work re-evaluates the CMIP6 assessment of the methane wetland emissions feedback in UKESM1 by taking account of wetland emissions’ sensitivity to both meteorology and carbon dioxide.
This presentation demonstrates the need for including interactive methane in Earth System Models. By allowing changes in natural methane emissions to influence methane concentrations and climate, this novel capability enables scientists to determine the consequences of methane emission reduction policies or climate feedbacks on natural methane sources towards meeting global climate as well as global air quality targets.
How to cite: O'Connor, F., Folberth, G., Gedney, N., and Jones, C.: The role of an interactive methane cycle in climate sensitivity and climate feedbacks, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8532, https://doi.org/10.5194/egusphere-egu23-8532, 2023.
Wildfires produce serious and long-lasting effects on weather and climate by large dust and aerosol emissions. However, its remote impacts on clouds over the Southern Ocean (SO) and polar regions remain unxplored. Based on ship observations conducted during MARCUS feild campaign from November, 2017 to March, 2018, a fire index (FI) is defined along the ship track by a lagrangian particle dispersion model (FLEXPART) combined with a daily high-resolution wildfire burned area dataset. Correaltions between this fire index and observed aerosol and CCN concentrations are analyzed to explore potential impacts of wildfire on SO clouds and its latitudinal variations. Our results show that the correlations between FI and aerosol concentrations are significant over the SO, which means the Autralia wildfire could affect the SO clouds reaching far to 70°S. The most significant positive correlations are found in the range of 40°S-55°S between FI and aerosol and CCN concentrations, with correlation coefficients of 0.65 and 0.88 respectively.
How to cite: Ding, S.: Potential impacts of wildfire on Southern Ocean clouds, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-6282, https://doi.org/10.5194/egusphere-egu23-6282, 2023.
Understanding the link between anthropogenic emissions and radiative forcing remains a grand challenge in the field of climate research. Linkages arise between emissions, atmospheric chemistry and climate through the formation of secondary aerosols such as sulfate, nitrate and organic aerosols. Sulfur dioxide (SO2) is an important aerosol precursor with the largest sources coming from anthropogenic activity. Unlike well-mixed greenhouse gases, anthropogenic aerosols are heterogeneously distributed because of localised emissions and the short atmospheric residence time. Thus SO2 conversion to aerosol is dictated by its emission location and the locally available oxidants; both of which are changing rapidly and disparately with time.
This work uses the UKESM1 to investigate the modelled response of sulfate aerosol properties and cloud properties to emissions increases and oxidant changes over the period 1850-2014. We compare modelled hydrogen peroxide, which is important for SO2 oxidation, with observations. From an analysis of the CMIP6 and AerChemMIP experiments, we show that there have been significant changes in the atmospheric oxidation processes of SO2 over this period with consequences for the calculated radiative forcing.
In UKESM1 historical experiments, the gas-phase reaction with hydroxyl radicals dominates the oxidation pathways in most regions. This channel is the most sensitive to oxidant changes and contributes to new aerosol particle formation. In contrast, in the aqueous-phase reaction, the oxidation of SO2 by ozone decreased in the European region in 1980 and oxidation by hydrogen peroxide increased in Eastern Asia in 2014. We present an analysis of the impacts of these sulfur oxidation changes on cloud properties and radiative forcing. Ultimately, this work contributes to the improvement of our process-level understanding of Earth system models that interactively simulate aerosol from precursors and aims to improve the accuracy of aerosol radiative forcing predictions.
How to cite: Sakulsupich, V., Griffiths, P. T., and Archibald, A. T.: The role of sulfur oxidation on cloud and aerosol properties in UKESM1 CMIP6 historical experiments, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-423, https://doi.org/10.5194/egusphere-egu23-423, 2023.
A grand challenge in the field of chemistry-climate modelling is to understand the connection between anthropogenic emissions, atmospheric composition and the radiative forcing of trace gases and aerosols. The AerChemMIP model intercomparison project, part of CMIP6, aims to understand the role of near-term climate forcers, aerosol and chemistry and includes experiments focused on tropospheric ozone.
We present an analysis of the trends in tropospheric ozone budget in the UKESM1 and other models for which diagnostic data is available from CMIP6 experiments. We focus on the historical period, and evaluate trends in ozone budget terms of chemical production and loss of ozone as well as physical processes such as transport and deposition. We include AerChemMIP attribution experiments such as histSST-piCH4, to quantify the effect of individual emissions and forcing changes on the historical ozone burden and budget. We include a comparison of ozone budget over ocean basins with data from recent ATom field campaigns.
How to cite: Griffiths, P., Shin, Y., Keeble, J., and Archibald, A.: Tropospheric ozone budget in AerChemMIP experiments, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-7364, https://doi.org/10.5194/egusphere-egu23-7364, 2023.
Formaldehyde (HCHO), hydrogen peroxide (H2O2) and organic hydroperoxides (ROOH) play a key role in atmospheric oxidation processes. They act as sources and sinks for HOx radicals (OH + HO2), with OH as the primary oxidant that governs the atmospheric self-cleaning capacity. In this study, we use in situ observations in the marine boundary layer (MBL) to calculate trace gas budgets, determine dry deposition velocities and evaluate results of the general circulation model EMAC (ECHAM5/MESSy2 Atmospheric Chemistry).
The dataset was obtained during the AQABA (Air Quality and climate change in the Arabian BAsin) ship campaign around the Arabian Peninsula in summer 2017. This region is famous for high levels of anthropogenic air pollution related to the oil and gas industry, especially in the areas around the Suez Canal and the Arabian Gulf. High levels of air pollution with up to 12 ppbV HCHO, 2.3 ppbV ROOH but relatively low levels of H2O2 (≤ 0.5 ppbV) were detected over the Arabian Gulf.
We find that EMAC predicted mixing ratios of HCHO and ROOH mostly within a factor of 2, while the model overestimated ROOH in cleaner conditions and it failed to resolve the encountered high pollution events over the Arabian Gulf. Dry deposition velocities (Vdep) were determined for HCHO and H2O2 during night with 0.77 ± 0.29 cm s–1 for HCHO and 1.03 ± 0.52 cm s–1 for H2O2 over the Arabian Sea, which were matched by EMAC. Vdep was underestimated over the Mediterranean Sea by more than a factor of 2, which was mostly related to the models resolution and its wind speed dependency. Determination of the photochemical budget of H2O2 revealed overestimated HOx in EMAC, which resulted in an elevated net photochemical production over most regions. Results of the regional model WRF-Chem (Weather Research and Forecasting-Chem) increased the accuracy of H2O2 for most regions, while the model did not resolve the complex air pollution encountered over the Arabian Gulf, which may lead to missing anthropogenic emissions in the region.
How to cite: Dienhart, D., Brendel, B., Crowley, J. N., Eger, P. G., Harder, H., Martinez, M., Osipov, S., Pozzer, A., Rohloff, R., Schuladen, J., Tauer, S., Lelieveld, J., and Fischer, H.: Oxidation precursors around the Arabian Peninsula – Evaluation of EMAC model results with ship-based measurements of HCHO, H2O2, ROOH and HOx, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-10731, https://doi.org/10.5194/egusphere-egu23-10731, 2023.
Studies have demonstrated that black carbon (BC) tends to be underestimated by models in general, while NO2 and CO columns are also underestimated, although surface measurements are reasonable. These findings are at odds with increased regulations and incentives to improve air quality and address climate altering species.
Recent advances in analyzing large datasets allows new analytical methods to detect signals and quantify patterns among different in-situ species, which were not previously realized. This work adopts one such approach merging mass conservation, number conservation, first order thermodynamics and chemistry, single-particle MIE modeling, and remotely sensed measurements across the UV, VIS, and NIR in tandem. Using basic thermodynamical relationships of combustion under different energy use conditions to constrain the ratios between co-emitted species, first order in-situ chemistry, and advective and pressure-based transport, emissions and uncertainties of BC, CO, and NO2 are quantified. The total errors are explored in depth based on boundaries established from the first order physical laws and mathematical bootstrapping, with the overall error generally observed to be smaller than the day-to-day variability.
The significance of day-to-day, week-to-week, and grid-to-grid variation are quantified. This is especially true in the regions undergoing the most change. The impacts of dynamical transport, chemical-decay, thermodynamic initiation, and in-situ interactions with UV radiation are attributed using additional measurements not used to fit the mass-conserving model free approach used in this work. This work relies on AERONET, SONET, OMI, TROPOMI, GEMS, MOPITT, MISR, CEMS, and other ground-based platforms.
A few conclusions are discussed. First, regulations are working in urban centers and at large sources including powerplants, steel plants, and concrete plants, with overall emissions being reduced for at least one and in many cases two species. Second, there are large increases in suburban and rural areas, including in regions previously unidentified as being emission s free. Third, the effects of biomass burning are clearly identified and attributed, even in regions which were previously thought to be nearly completely controlled by urban sources, such as the megacities of Hong Kong, New Delhi, and Shanghai. Fourth, attribution has determined that emissions, UV radiation, and long-range transport are all significant. Fifth, there are biases in the observed TOA radiative forcing, in which a small but significant percentage of the total BC outcomes have a positive radiative forcing, and the median values are far less negative than current models can capture. Sixth, the concept of TOA and ABS radiative forcing per unit of AOD is found to not be reasonable, and a new framework is demonstrated that accounts for more than 90% of the possible cases computed.
How to cite: Cohen, J.: Top-Down Model-Free Computed Emissions, Size, Mixing State, and Radiative Forcing of BC, CO, and NOx: Increased Emissions and Less Negative Radiative Forcing in Rural Areas Coupled with Reduced Emissions and More Variable Radiative Forcing in Urban Areas, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-8966, https://doi.org/10.5194/egusphere-egu23-8966, 2023.
Dimethyl sulfide (DMS), which originates from phytoplankton, is the major natural source of sulfur compounds in the atmosphere. The oxidation products of DMS can form aerosols, which contribute to the formation of clouds, making them important for rain and the radiative balance of the planet. Additionally, due to DMS naturally occurring above oceans, an oxidation product of DMS, methanesulfonic acid (MSA), has been used to determine sea ice extent in ice cores up to 300 years in the past. However, due to gaps in the oxidation pathway of DMS, there are large uncertainties in the modelling of MSA formation. The aim of this work is to reduce the uncertainties in the DMS oxidation pathway, improving the modelling of the major products.
This project uses the KPP wrapper, BOXMOX, to compare box model outputs to chamber experiments from Albu et al. [1], Arsene et al. [2] and Ye et al. [3]. This comparison allows for an assessment of a near-explicit mechanism used in box models (the Master Chemical Mechanism) and a reduced mechanism useful for global models (CRI-Strat) regarding DMS oxidation in both low and high NOx environments. This work presents the outcomes from this assessment and recommendations for the mechanisms to improve their modelling of DMS oxidation.
[1] Albu, M.; Barnes, I.; Becker, K. H.; Patroescu-Klotz, I.; Benter, T.; Mocanu, R. In Simulation and Assessment of Chemical Processes in a Multiphase Environment, Barnes, I., Kharytonov, M. M., Eds.; Springer Science: Dortdrecht, 2008, pp 501–513.
[2] Arsene, C.; Barnes, I.; Becker, K. H.; Mocanu, R. Atmos. Environ. 2001, 35, 3769–3780.
[3] Ye, Q.; Goss, M. B.; Krechmer, J. E.; Majluf, F.; Zaytsev, A.; Li, Y.; Roscioli, J. R.; Canagaratna, M.; Keutsch, F. N.; Heald, C. L.; Kroll, J. H. Atmos. Chem. Phys., 2022, 22, 16003–16015.
How to cite: Jacob, L., Giorio, C., and Archibald, A.: Assessment of dimethyl sulfide atmospheric oxidation mechanisms, used in both box models and global models, through the comparison with previous experiments, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-15130, https://doi.org/10.5194/egusphere-egu23-15130, 2023.
In this study, we developed a statistical-dynamical model that predicts the concentration of particulate matter in Korea 2-3 months in advance using the correlation between meteorological and climate factors and presented its performance. Temperature and atmospheric circulation around the Arctic Ocean considering the predictive performance of the National Centers for Environmental Prediction (NCEP) climate forecast system version 2 (CFSv2), the concentration of particulate matter in winter in Korea, and the correlation between meteorological and climate factors, potential predictors such as sea surface temperature in the Bering Sea region and sea level pressure in the Atlantic region were discovered. Using this, a multiple linear regression model was constructed between the average concentration of particulate matter during the winter of that year and latent factors for the second half of October and the first half of November in NCEP CFSv2, respectively. Seasonal predictions were made for the concentration of particulate matter in winter for a total of 20 years from 2001 to 2020. The result of the winter predicted in the second half of October showed r=0.49. And the result predicted in the first half of November showed a predictive performance of r=0.45. Considering the linear trend of particulate matter reduction, which was strong during the study period, r=0.72 in the second half of October and r=0.71 in the first half of November. This is judged to be the result of maximizing climate prediction performance considering the relatively long time scale of seasonal forecasting. In addition, additional forecasting ability can be expected through improved predictability of climate prediction models such as multi-model ensemble technology. However, although the results of the dynamical model were reflected, there are still limitations of the statistical model, and additional research is needed, such as problems due to limitations in observational data.
How to cite: Choi, J., Jeong, J.-H., Woo, S.-H., Jeong, J.-Y., Park, S., and Yoon, J.-H.: A study on seasonal forecasting of air quality in East Asia using statistical-dynamical methods, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-14813, https://doi.org/10.5194/egusphere-egu23-14813, 2023.
Climate change and its associated risks are becoming more and more prominent. Stratospheric solar geoengineering with sulfuric acid aerosols has been put forward as a way to temporarily mitigate some of the risks of climate change and is inspired by the cooling effect of large eruptions of tropical volcanoes. To learn more about the opportunities and dangers associated with stratospheric solar geoengineering, it is important to investigate the strategy beforehand, e.g., by means of climate modelling. To better understand the sources of model uncertainties, the Geoengineering Model Intercomparison Project (GeoMIP) introduced stratospheric solar geoengineering scenarios for an easier comparison of different models. Most models participating in GeoMIP either have no interactive chemistry or simplified aerosol micro-physics. In this study we perform the G6sulfur experiment with SOCOLv4, an atmosphere-ocean-aerosol-chemistry climate model. In the G6 sulfur experiment the aim is to bring the global average temperature of the SSP5-8.5 to the levels of the SSP2-4.5 sceanrio.
For the calibration we ran three different tests in order to analyse the sensitivity of the aerosol burden to the order in which the microphysical processes are simulated at each timestep - nucleation of new particles from H2SO4 vapours and condensation of H2SO4 on pre-existing particles. One experiment had nucleation first, one had condensation first and finally one had nucleation first but with an added subsubstep where coagulation is called again. For all these runs we used an injection of 5 TgS/year. In the run with nucleation first the global stratospheric aerosol burden is 25% bigger than in the run where condensation is called first and 10% bigger than in the run with 2 subsubsteps. This leads to a cooling effect over 2032-2047 which is 1.02 K for nucleation first, 0.95 K for the run with the additional substep and 0.65 K for condensation first. Based on the cooling efficiency of the 5 TgS/year injection, we then derive a time-dependent emission, to keep global mean surface temperatures close to the SSP2-4.5 scenario.
For the G6sulfur experiment we chose the setup of the run with 2 subsubsteps and performed three ensemble members to get a better understanding of the uncertainties within the model. We will discuss the effects on stratospheric aerosol burden, radiative forcing, temperature, ozone and precipitation changes and compare our results to other GeoMIP models. This will work provides useful insights concerning the radiative and climatic impacts of stratospheric aerosols on climate, elucidating the impact of uncertainties in the modelling of microphysical processes.
How to cite: Wunderlin, E., Chiodo, G., Sukhodolov, T., Vattioni, S., Visioni, D., and Tilmes, S.: Analysis of the GeoMIP G6sulfur experiment with SOCOLv4, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-15821, https://doi.org/10.5194/egusphere-egu23-15821, 2023.
Airborne aerosols can alter incoming solar radiation inducing different radiative responses, yet the potential ecological effects of changes in the degree of linear polarization (DoLP) by the light alteration remain largely unknown. Light polarization is an important navigational cue for honeybee for which a threshold intensity (i.e., the DoLP) for a reliable response is known as 15%. Here, we quantify the relationship between the mass concentration of airborne fine particulate matter (PM2.5) and the DoLP by ground-based observation to provide an estimate of how the quantity of PM2.5 changes the DoLP in general and how these changes will impair navigation of honeybee by limited-visibility at the global level. We find that the PM2.5 mass concentration exponentially decreases the DoLP, reducing the average and maximum DoLP, and the size of area containing perceivable polarization information by honeybee over the sky. Applying these results to global air quality prediction models, EMAC, MPI-ESM1.2-HAM, MIROC-ES2 under a BaU (for EMAC) and SSP370 (for MPI-ESM1.2-HAM, MIROC-ES2L) scenario, we find that projected areas and the number of days of limited-visibility that honeybee experience increases globally on average. Our estimates capture almost year-round risk hotspots of limited-visibility over sub-Saharan Africa, Eastern Mediterranean, Southeast Asian regions in 2050. In particular, India is projected to experience approximately a 10 folds increase in the number of days of limited visibility. Developing countries are more vulnerable to degrading air quality than developed countries in terms of limited-visibility for honey bees. Overall, our study demonstrates degrading air quality in 2050 as a result of business-as-usual emissions of air pollutants can affect bee navigation, threatening fundamental plant-pollinator interactions. Further, warming climate will exacerbate this impact.
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. RS-2022-00155875).
How to cite: Cho, Y., Jeong, S., and Chang, D. Y.: Global projection of potential effects of future air quality on bee visual navigation , EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-13947, https://doi.org/10.5194/egusphere-egu23-13947, 2023.
Regional air quality over East Asia, including South Korea, has been a center of public attention recently because of a few episodes in which very high particulate matter (PM) concentrations have been observed. Predicting PM variation with lead time of a few hours up to days is one of the key areas that the governments are working on because it can benefit from early warning system to short-term mitigation effort. In this study, the influence of synoptic weather conditions on regional air quality was investigated with the occurrence frequencies of PM episodes as a function of various synoptic weather patterns during winter and spring. (1) During winter, dry moderate (DM) types occur frequently alongside high PM cases (24-h mean PM10 concentration > ). The composite weather map showed a weak northwesterly wind field as a potential cause. On the contrary, it is interesting to note that dry polar (DP) types can be associated with low PM cases (24-h mean PM10 concentration < ) as well as high PM depending on near-surface wind speed. (2) Furthermore, during spring, DM and dry tropical (DT) types were found to be highly correlated with high (much higher) PM concentrations, likely because of the enhanced static stability in the lower troposphere. It should be noted that PM concentration depends on the lower atmospheric stability. The close relationship between synoptic weather patterns and PM concentration suggests that synoptic weather can play an important role in regional air quality.
How to cite: Lee, D., Kim, H. C., Kim, K., Yun, S. B., Yang, J.-H., and Kim, D.-H.: Relationship between synoptic weather pattern and surface Particulate Matter (PM) during winter and spring seasons over South Korea, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-4612, https://doi.org/10.5194/egusphere-egu23-4612, 2023.
The large reduction in anthropogenic aerosol emissions across China in recent years has improved China’s air quality but also caused changes in radiative forcing. Some studies confirmed the reduction of aerosols over China cause a positive radiative forcing locally and play an important role in Arctic warming. However, few studies have differentiated and quantified the radiative forcing of different aerosol components including BC and sulphate. Here, we aim to understand the reduction of black carbon (BC) and SO2 emissions over China from 2008 to 2016 under a series of policies enacted by the Chinese government and to determine the change in radiative forcing both locally and remotely. We use the Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants (ECLIPSE) emission inventory to represent China's emissions of the two pollutants during this period and use the United Kingdom Earth System Model (UKESM) v-1 to calculate the individual radiative forcing due to changes in all anthropogenic aerosols, China BC only, and China SO2 only between 2008 and 2016. Finally, we use the temperature coefficients of individual pollutants at different latitude bands to calculate the temperature responses. Our results show the largest reduction of BC over China was from the residential and energy sectors, while the reduction in SO2 emissions from energy and industrial sources were significant. Compared with other inventories, ECLIPSE overestimates the reduction of emissions but shows the same trend. The aerosol radiative forcing over China locally due to the large Chinese emission reductions of BC and SO2 are -0.30±0.01Wm-2 and 1.03±0.07 Wm-2, respectively, which jointly accounts for more than 80% of the total aerosol radiative forcing calculated by the model from all anthropogenic aerosol emission sources. In addition, changes in BC and SO2 over China together contributed to a positive radiative forcing of 0.18 Wm-2 across the North Pacific. However, BC and sulphate are not major contributors to changes in Arctic radiative forcing. The temperature response due to BC (-0.008 ℃) and sulphate (0.060 ℃) is most pronounced locally in the mid-latitudes, while the temperature response in the low and high latitudes is small. This study bridges the gap on changes in radiative forcing due to anthropogenic emissions reductions in China and quantifies the contributions of BC and sulphate aerosols to better understand the impact of air pollution emission control policies on climate.
How to cite: Chen, Y., R. Arnold, S., and T. Turnock, S.: Radiative Effects of Recent Changes in PM2.5 Pollution over China and Local and Remote Climate Impacts, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-7597, https://doi.org/10.5194/egusphere-egu23-7597, 2023.
The COVID-19 pandemic is reshaping the global trade and supply chains, and some developed countries may consider relocating strategic manufacturing operations out of China, providing new opportunities for some South and Southeast Asian countries. Since the shift of manufacturing is accompanied by redistribution of emission sources of air pollutants, the impacts on environment and human health of the countries directly involved and their neighbors, should be considered. We used the Community Earth System Model, the Integrated Exposure-Response (IER) model and Willingness To Pay (WTP) method, to simulate fine particulate matter (PM2.5) and the socio-economic responses to shifting manufacturing from China to Indonesia or India. Our results show that significant effects on PM2.5 related mortality and economic cost for these deaths were seen in many East, Southeast and South Asian countries, particularly those immediately downwind of these three countries. Transferring all of export-related manufacturing to Indonesia resulted in significant mortality decreases in China and South Korea by around 78k (5 per 100k) and 1k (2 per 100k) respectively, while Indonesia’s mortality significantly increased (73.7k; 29 per 100k), as well as India, Pakistan and Nepal. When manufacturing was transferred to India, mortality rates in East Asia show similar responses to the Indonesian scenario, while mortalities in India increased dramatically by 87.9k (6 per 100k), and mortalities in many neighbors of India also severely increased. Shifting manufacturing to India in our simulations led to more Asian countries showing significant changes in PM2.5 related deaths and economic costs than an equivalent shift to Indonesia. This is because of the maritime Indonesian setting as well as patterns of surface winds. Nevertheless, the economic costs for these deaths were much smaller than national GDP changes in China (0.9% of GDP vs. 18.3% of GDP), India (2.7% of GDP vs. 84.3% of GDP) or Indonesia (9.4% of GDP vs. 337% of GDP) due to shifting all of export-related production lines from China to India or Indonesia. Perhaps the most concerning aspect of this study is the damage to “innocent” victims of any manufacturing shifts in third countries that do not see any domestic economic gains. Morally, part of the benefits of economic activity should be used to compensate the neighboring communities where mortality increases occur.
How to cite: Ran, Q., Lee, S.-Y., Zheng, D., Chen, H., Yang, S., Moore, J., and Dong, W.: How would shifting manufacturing from China to Indonesia or India impact human health and social economy?, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-3715, https://doi.org/10.5194/egusphere-egu23-3715, 2023.
