In 2023, the global mean temperature soared to almost 1.5°C above the preindustrial level, surpassing the previous record by about 0.17°C. Previous best-guess estimates of known drivers, including anthropogenic warming and the El Niño onset, fall short by about 0.2°C in explaining the temperature rise. This gap persisted in 2024, during which the stronger El Niño contribution resulted in an even higher global annual-mean temperature, exceeding the symbolic 1.5°C threshold. Using satellite and reanalysis data, we identified a record-low planetary albedo as the primary factor bridging this gap. The decline is apparently caused largely by a reduced low-cloud cover in the northern mid-latitudes and tropics, in continuation of a multiannual trend. Further exploring the low-cloud trend and understanding how much of it is due to internal variability, reduced aerosol concentrations, or a possibly emerging low-cloud feedback will be crucial for assessing the present and expected future warming.
How to cite: Goessling, H., Rackow, T., and Jung, T.: Recent global temperature surge intensified by record-low planetary albedo, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15920, https://doi.org/10.5194/egusphere-egu25-15920, 2025.
Incoming solar radiation drives the Earth’s climate system. Long-term surface observations of solar radiation reaching the surface have shown decreasing or increasing trends in different regions of the world in the past several decades, indicating the change of atmospheric components that reflect and/or absorb the solar radiation. This study investigates the roles of aerosols and climate change in determining the surface radiation trends through the change of anthropogenic emission, aerosol-radiation interaction, and aerosol-cloud interactions. With a series of model simulations and analysis of ground-based observations and satellite-derived data products, we will 1) estimate the relative importance of aerosols, clouds, and other radiatively active atmospheric trace gases on the surface radiation budget, 2) compare the relative magnitudes of effects from atmospheric components (aerosols, clouds, and trace gases) and atmospheric processes (aerosol-radiation interactions and aerosol-cloud interactions) in determining the surface radiation trends, and 3) assess the consequences of climate change and anthropogenic emission trends in the change of surface radiation in different regions of the world.
How to cite: Chin, M., Bian, H., Wild, M., Barahona, D., Yu, H., Qian, Y., Darmenov, A., Stackhouse, P., Loeb, N., Pinker, R., and Zhang, Y.: Multi-Decadal Trends of Solar Radiation Reaching the Surface Determined by Aerosol-Cloud-Radiation Interactions, Climate Change, and Anthropogenic Emissions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4577, https://doi.org/10.5194/egusphere-egu25-4577, 2025.
Observations have recorded significant decadal changes in the global surface solar radiation (SSR) over the past, a phenomenon known as the ‘global dimming’ and ‘brightening’. Many studies suggest that changes of SSR are dominated by aerosols, clouds, and other influences at the atmosphere. However, due to the lack of suitable data and methodology, there are few global evaluations and quantitative work that reveal the relative importance of impacting factors on the SSR trends. In this study, a linear regression method is used to investigate the driving factors of global SSR and to quantify their contributions to the long-term change and distribution of SSR. Based on a reanalysis dataset, from 2000 to 2023, the distributions and trends of SSR can be well explained by the linear regression model, with crucial variables such as aerosol optical depth (AOD), cloud radiative effect and water vapor as predictors. The model performs particularly well at low and middle latitudes. We find that under all sky condition, cloud radiative effect causes approximately 70% of the variation in SSR, which has the strongest influence on SSR among the other predictors. In addition, all-sky SSR also shows very high sensitivity to water vapor and AOD.
How to cite: Xiao, H., Huang, Y., Yu, Q., and Peng, Y.: Contributions of Driving Factors to Variations in Global Surface Solar Radiation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12299, https://doi.org/10.5194/egusphere-egu25-12299, 2025.
Inhomogeneities in the sunshine duration (SSD) observational series, caused by non-climatic factors like China’s widespread transition from manual to automatic SSD recorders in 2019 or station relocations, have hindered accurate estimate of near-surface solar radiation for the analysis of global dimming and brightening as well as related applications, such as solar energy planning and agriculture management. This study compiled raw SSD observational data from 1961 to 2022 at more than 2,200 stations in China and clearly found that the improved precision from 0.1 hour to 1 minute following the instrument update in 2019 led to a sudden reduction in the frequency of zero SSD from 2019 onwards, referred to as the day0-type discontinuity. For the first time, we systematically corrected this known day0-type discontinuity at 378 stations (17%) in China, resulting in an SSD series with comparable frequencies of zero value before and after 2019. On this base, we constructed a homogenization procedure to detect and adjust discontinuities in both the variance and mean of daily SSD from 1961 to 2022. Results show that a total of 1,363 (60%) stations experienced breakpoints in SSD, of which ~65% were confirmed by station relocations and instrument replacements. Compared to the raw SSD, the homogenized SSD was more continuous to the naked eye for various periods, and presented weakened dimming across China from 1961 to 1990 but a non-significant positive trend by a reduction of 60% in the Tibetan Plateau, suggesting that the homogenized SSD tends to better capture the dimming phenomenon. The northern regions continued dimming from 1991 to 2022 but the southern regions of China brightened slightly. The implementation of the Action Plan for Air Pollution Prevention and Control since 2013 contributed to a reversal of SSD trend thereafter, which was better reflected in the homogenized SSD with a trend shift from -0.02 to 0.07 hours·day-1/decade from 2013 to 2022 in China, especially in heavily polluted regions. Besides, the relationships of cloud cover fraction and aerosol optical depth with SSD were intensified in the homogenized dataset. These results highlight the importance of the homogenized SSD in accurately understanding the dimming and brightening phenomena. The homogenized SSD dataset is publicly available for community use at https://yanyihe-rad.github.io/files/homog-daily-ssd-China-v1.0.mat.
How to cite: He, Y., Wang, K., Yang, K., Zhou, C., Shao, C., and Yin, C.: Homogenized daily sunshine duration over China from 1961 to 2022, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14211, https://doi.org/10.5194/egusphere-egu25-14211, 2025.
Defined as the proportion of solar radiation transmitted through the atmosphere to the Earth's surface, the clearness index (CI) is a vital parameter widely applied in characterizing atmospheric transmittance and sky conditions. However, its application accuracy remains inadequately investigated. This study enhances the understanding and application of CI through three key advancements:
- Establishing CI Thresholds for Sky Conditions: Standardized CI thresholds for clear-sky (>0.7) and overcast-sky (<0.2) conditions are proposed using synoptic total cloud cover, refining the previously broad ranges. Their logarithmic relationship with solar elevation angles enables accurate identification of sky conditions throughout the day.
- Advancing Physical Threshold Testing: A CI-DF polynomial envelope, combining CI and diffuse fraction (DF), is introduced to enhance the physical threshold testing procedure. This innovation automatically and effectively filters out outliers, particularly the often-overlooked abnormally low values, thus improving the quality control of surface observations.
- Developing a Radiation Decomposition Model: A model is established to accurately estimate direct radiation at daily and hourly scales, leveraging the logistic growth relationship between CI and the direct clearness index. This supports the growing global transition to renewable energy applications.
These findings highlight the importance of more accurate applications of CI in atmospheric radiation and energy meteorology studies.
How to cite: Wang, Y.: Enhancing the Understanding and Application of the Clearness Index, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-3081, https://doi.org/10.5194/egusphere-egu25-3081, 2025.
The Central India (CI), wherein synoptic-scale disturbances (monsoon lows and depressions) frequently pass through during the monsoon season, is identified as a monsoon core zone where detailed long-term atmospheric measurements of convection, clouds, precipitation, and radiation are overdue.
Considering the importance of observational and analytical research in this area, an Atmospheric Research Testbed in Central India (ART-CI) is established by the Ministry of Earth Sciences, Government of India. ART-CI is a huge permanent observational facility envisioned as a national research testbed with multiple laboratories (aerosol, radiation, cloud and precipitation measurements) and scientific user facilities similar to the international Atmospheric Radiation Measurement (ARM) site, USA.
Our climate system is largely determined by the Earth’s Radiation Budget, and is significantly influenced by drastic changes in clouds, aerosols, and greenhouse gases. Hence, to have long-term surface observations for monitoring the changes/trends in the Surface Radiation Budget, important for climate monitoring and prediction, Atmospheric Radiation Laboratory (ARL) is established in August 2023, as a part of the major research facility ART-CI. At ARL, a suite of radiation sensors was installed for continuous measurements of all components of solar and terrestrial radiation (such as total, direct and diffuse shortwave, long-wave, net and UV radiations) co-located with all other atmospheric data instrumentation.
Thus, this unique facility will have an extensive set of state-of-the-art observational systems that will provide continuous observations of land surface properties and surface energy budget. Site description, instrumentation and science plan of this new facility with initial results will be presented.
How to cite: PadmaKumari, B., Vasudevan, A. K., Sahoo, U. K., Victor, J., Lian, Y., Tr, L., Nikam, M., Kalgutkar, S., and Govindan, P.: Atmospheric Radiation Laboratory (ARL) in Monsoon core zone: A unique research facility in Central India, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-633, https://doi.org/10.5194/egusphere-egu25-633, 2025.
Dust aerosols significantly affect the shortwave (SW) radiation budget from global to regional scales. This effect strengthens during intense dust outbreaks taking place with variable frequency and features over and near to the great world deserts. The greater Mediterranean Basin is such a region, frequently undergoing dust episodes originating from the nearby Sahara Desert. In the present study, a climatological assessment of the direct SW radiative effects (DREs) of intense Mediterranean dust episodes is made for the first time. Specifically, the modification of the top-of-atmosphere (TOA), atmospheric and surface SW radiative fluxes caused by 162 spatially extended intense dust episodes that took place from 2005 to 2018 is estimated using the FORTH spectral radiative transfer model (RTM). Also, the consequent modification of the regional atmospheric thermal structure and dynamics due to these DREs is computed, aiming to shed light on the role of dust aerosols on regional climate. The RTM computations are driven by a synergy of contemporary satellite (ISCCP-H) and reanalysis (MERRA-2) climatological data.
The reliability of the dust DREs (DDREs) is ensured by comparisons of the model outputs with reference fluxes at the region’s surface (BSRN stations) and TOA (CERES). The results are satisfactory indicating a nice correlation with BSRN and CERES (R values equal to 0.95 and 0.98, respectively) and a slight underestimation (5.4%) at surface and overestimation at TOA (2.7%). During the 162 intense dust episodes the surface of the Mediterranean Basin is cooled by up to -72 W/m2 on average, while the atmosphere is correspondingly heated by up to 75 W/m2. At TOA opposite effects are induced, namely a planetary heating (up to 26 W/m2) over Africa and a cooling (as much as -20 W/m2) over the Mediterranean Sea. These values are larger (up to 100 W/m2) on a seasonal basis and even stronger on a daily or hourly basis. Besides, the DDREs induce an atmospheric heating up to about 0.4 K/3-hours on average, while this heating is as strong as 2.5 K during the time interval 12:00-15:00 of the dust episode days, creating a significant positive buoyancy over the dust affected areas.
How to cite: Hatzianastassiou, N., Gavrouzou, M., Korras-Carraca, M.-B., Stamatis, M., Lolis, C., Mihalopoulos, N., Matsoukas, C., and Vardavas, I.: Modification of the shortwave radiation budget of the Mediterranean Basin during intense dust episodes (2005-2018), EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18785, https://doi.org/10.5194/egusphere-egu25-18785, 2025.
Accurate solar irradiance measurements are critical for optimising solar energy systems, understanding atmospheric processes, and advancing climate research. Pyrheliometers, which provide Direct Normal Irradiance (DNI) measurements over a broad spectral range, are widely used due to their simplicity, cost-effectiveness, and ease of deployment. However, they cannot provide detailed spectral information, which limits their application in advanced studies requiring wavelength-specific insights. In contrast, the Bi-Tec Sensor (BTS) spectroradiometer system measures spectral solar irradiance from 300 nm to 2150 nm with high spectral resolution, covering almost ~96.5% of the solar spectrum, and is traceable to the International System of Units (SI). This detailed spectral data enables in-depth studies of solar energy distribution across different wavelengths but excludes approximately 3.5% of the total solar spectrum in the infrared region (2150–5000 nm).
To overcome this limitation and enable full-spectrum comparisons, this study utilized libradtran, an atmospheric radiative transfer model, to extend the BTS spectral range, whereas due to the requirement of computational resources and expertise, A comparatively simpler functional model was developed based on libradtran simulations, focusing on critical parameters such as solar zenith angle, water vapor, and aerosol properties. This function closely matched the results from libradtran and achieved high precision with a mean value of 96.52% and a standard deviation of 0.20% that can be used to accurately extend the BTS measurements to cover the full spectrum. The comparison between pyrheliometer and BTS spectroradiometer yields a mean ratio of 0.9897 with a standard deviation of 0.0149, achieving a good correlation with pyrheliometer data while maintaining precise spectral details.
The results confirm that BTS spectroradiometers, combined with the spectral extension model, provide an effective and detailed alternative for solar irradiance monitoring. Unlike pyrheliometers, BTS instruments deliver wavelength-specific data crucial for advanced solar energy studies and atmospheric research. Moreover, integrating the extension model into BTS systems simplifies data processing, making high-quality measurements accessible for non-expert users and resource-limited regions.
This approach bridges the gap between the spectral detail of BTS systems and the broad range of pyrheliometers, offering a reliable solution for comprehensive solar irradiance measurements. These findings mark a step forward in solar energy research and environmental monitoring, with the potential to address global data gaps in cost-effective and scalable ways.
How to cite: Jaine, D. and Gröbner, J.: Comparison of solar spectral irradiance measurements with pyrheliometer total solar irradiance data., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6703, https://doi.org/10.5194/egusphere-egu25-6703, 2025.
The ecRad scheme is the latest radiative transfer scheme provided by the European Centre for Medium-range Weather Forecast (ECMWF), and is notably operational in the ECMWF’s Integrated Forecasting System (IFS) since 2017. Recent developments of ecRad enable it both to run using ecCKD high resolution gas-optics models and to produce surface shortwave spectral fluxes. The combination of both features allow ecRad to produce fine surface shortwave spectral fluxes, e.g., over a 310–315 nm spectral band.
We assessed this capability after embedding ecRad (v1.5.0) in the MAR (Modèle Atmosphérique Régional) regional climate model (v3.14). For this purpose, we used ground-based spectral observations captured by the Royal Belgian Institute for Space Aeronomy at Uccle (Belgium; 50.797° N, 4.357° E) from 2017 to 2020, in the 280–500 nm range and with a precision of 0.5 nm. After carefully tuning both MAR and ecRad and configuring fine spectral bands over the 280–500 nm range, we ran a MAR simulation over Belgium for the same period as the Uccle spectral observations.
After integrating the spectral observations on the same bands as configured in our MAR/ecRad simulation, we compared both time series of spectral fluxes at Uccle. Our evaluation yielded correlation coefficients ranging from 0.9 to 0.93 for all bands above 295 nm and low biases for all bands. As our spectral fluxes cover the ultraviolet (UV) range, we tried to predict UV indices with MAR/ecRad spectral fluxes. The UV index is a metric used to inform the public about how much harmful ultraviolet radiation reaches the Earth’s surface at a given time, and consists of a weighted integral of spectral fluxes over the UV range. Our model-based and observations-based UV indices are in very good agreement, though the former falls short of finding the highest UV indices of the latter, due to the ozone mixing ratios in MAR not varying on a daily basis.
Author's note: this research work is detailed in the paper "Inclusion of the ECMWF ecRad radiation scheme (v1.5.0) in the MAR model (v3.14), regional evaluation for Belgium and assessment of surface shortwave spectral fluxes at Uccle" currently available on EGUsphere in preprint (awaiting topic editor decision after referee comments and subsequent revision).
How to cite: Grailet, J.-F., Hogan, R. J., Ghilain, N., Bolsée, D., Fettweis, X., and Grégoire, M.: Evaluation of surface shortwave spectral fluxes at Uccle produced by the ECMWF ecRad radiation scheme (v1.5.0) embedded in the MAR regional model (v3.14) and prediction of UV indices, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17633, https://doi.org/10.5194/egusphere-egu25-17633, 2025.
The response of the Earth system to radiative perturbations is governed by a combination of fast and slow feedbacks. Slow feedbacks are typically activated in response to changes in ocean temperatures on decadal timescales and often manifest as changes in Earth-system state with no recent analogue. On the other hand, fast feedbacks can be activated in response to rapid atmospheric physical processes on timescales of weeks and are already operative in the present-day weather system. This distinction implies that the physics of fast radiative feedbacks is present in the historical reanalyses that have served as the training data for many of the most successful recent machine-learning-based emulators of weather. In addition, these feedbacks are functional under the historical boundary conditions pertaining to the top-of-atmosphere radiative balance and sea-surface temperatures. We discuss our work using historically trained weather emulators to characterize and quantify fast radiative feedbacks without the need to retrain for prospective Earth system conditions.
How to cite: Collins, W. and Mahesh, A.: Examining fast radiative feedbacks using machine-learning-based emulators of weather, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13923, https://doi.org/10.5194/egusphere-egu25-13923, 2025.
Contrail cirrus is regarded to be the largest contributor to aviation induced global warming based on classical radiative forcing and exceeds the corresponding climate impact of accumulated air traffic CO2 emissions. However, recent studies indicate that the leading role of contrail cirrus declines when using more advanced climate metrics, such as the effective radiative forcing, or even disappears when considering the induced surface temperature change.
Here we present results from climate model simulations to derive a fully self-consistent set of classical radiative forcings, effective radiative forcings and corresponding surface temperature changes for a contrail cirrus and CO2 perturbation. The simulations were extensively evaluated by feedback analysis in order to determine the origin of the reduced efficacy of contrail cirrus to warm Earth’s surface. When switching from classical radiative forcing to effective radiative forcing the impact of contrail cirrus decreases by 45% relative to CO2. Feedback analysis revealed a reduced formation of natural cirrus as the major reason, as contrail cirrus formation removes large parts of available ambient humidity. When looking at surface temperature change, the efficacy of contrail cirrus turned out to be reduced, even more, by 79% relative to CO2. Again, cloud feedbacks were found to be the major reason for the different behavior between the contrail cirrus and CO2 perturbation, however, in this case mainly triggered by decreasing low- and mid-level clouds in the CO2 simulation. The efficacy reduction is also supported by a larger negative lapse rate feedback (change of the vertical temperature slope) which is the result of a temperature dipole formed by contrail cirrus, with strongest warming rates directly below the contrail cirrus cloud base and decreasing strength towards surface.
How to cite: Bickel, M., Ponater, M., Burkhardt, U., Righi, M., Hendricks, J., and Jöckel, P.: The important role of feedback processes for contrail cirrus climate impact, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19022, https://doi.org/10.5194/egusphere-egu25-19022, 2025.
How to cite: Kappatou, C., LaCasce, J. H., Li, C., and Gjermundsen, A.: Investigating Bjerknes Compensation under the abrupt-4xCO2 CMIP6 experiment, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4868, https://doi.org/10.5194/egusphere-egu25-4868, 2025.
Recent decades have seen significant changes in land surface phenology, with earlier leaf development in northern ecosystems and diverse changes in autumn senescence, primarily attributed to climate change. These phenological changes feed back to Earth’s climate system by altering biogeochemical and biogeophysical processes at the land surface. However, little is known about the strength of these diverse effects on the Earth's energy balance, and whether their combination results in a net positive (warming) or negative (cooling) feedback to global warming.
Using a fully-coupled Earth system model (ESM) with an interactive global carbon cycle, we investigate the effects of land phenological changes on the Earth's energy balance and the subsequent biogeophysical and biogeochemical feedbacks. We prescribe transient shifts in leaf area index (LAI) in the ESM based on remote sensing estimates of phenological spring advancement (2.1 days per decade) and autumn delay (1.8 days per decade). Note these shifts are only prescribed for extratropical northern ecosystems, where robust phenological changes have been observed, however, the effect in the ESM is global including local and non-local effects. Our results provide a first quantification of the impact of these phenological changes on the processes affecting the Earth’s energy balance, namely, shortwave radiation through changes in surface albedo, surface sensible and latent heat fluxes, longwave surface emissions, ground heat flux, longwave radiation balance through greenhouse gases, and the overall radiative fluxes through cloud properties and planetary albedo.
We find that autumn LAI shifts have a stronger net effect than spring LAI shifts on the Earth's energy balance, and that these effects can compensate each other when they co-occur in the same year. Our simulations also reveal compensating effects between outgoing longwave and outgoing shortwave radiation at the top of the atmosphere, where the former points to a positive and the latter to a negative radiative forcing. Altogether, we report an average negative radiative forcing of 0.17 ± 0.1 W m-2 for a 10-day lengthening of the growing season, resulting in a global mean surface temperature cooling of 0.1 ± 0.03 °C. The effect is more pronounced in simulations when spring advancement and delay in senescence are prescribed separately in the ESM, amounting to a negative radiative forcing of 0.24 ± 0.21 W m-2 and 0.32 ± 0.25 W m-2 for a 10-day lengthening of the growing season, respectively. These simulations suggest that phenological changes triggered by global warming result in a net negative feedback to global warming. Future research is needed to confirm this first quantification and to investigate the saturation of phenological responses to global warming, which could weaken this cooling feedback effect in the future.
How to cite: Winkler, A. J. and the PhenoFeedBacks Team: Phenology's Net Cooling Effect as Feedback to Global Warming, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19629, https://doi.org/10.5194/egusphere-egu25-19629, 2025.
Monitoring the Earth Energy Imbalance (EEI) is of prime importance for a predictive understanding of climate change. Furthermore, monitoring of the EEI gives an early indication on how well mankind is doing in implementing the Paris Climate Agreement. EEI is defined as the small difference between the incoming energy the Earth receives from the Sun and the outgoing energy lost by Earth to space. The EEI is cumulated in the Earth climate system, particularly in the oceans, due to their substantial heat capacity, and results in global temperature rise. Currently the best estimates of the absolute value of the EEI, and of its long term variation are obtained from in situ observations, with a dominant contribution of the time derivative of the Ocean Heat Content (OHC). These in situ EEI observations can only be made over long time periods, typically a decade or longer. In contrast, with direct observations of the EEI from space, the EEI can be measured at the annual mean time scale. However, the EEI is currently poorly measured from space, due to two fundamental challenges. The first fundamental challenge is that the EEI is the difference between two opposing terms of nearly equal amplitude. Currently, the incoming solar radiation and outgoing terrestrial radiation are measured with separate instruments, which means that their calibration errors are added and overwhelm the signal to be measured. To make significant progress in this challenge, a differential measurement using identical intercalibrated instruments to measure both the incoming solar radiation and the outgoing terrestrial radiation is needed. The second fundamental challenge is that the outgoing terrestrial radiation has a systematic diurnal cycle. Currently, the outgoing terrestrial radiation is sampled from the so-called morning and afternoon Sun-synchronous orbits, complemented by narrow band geostationary imagers. Recently the sampling from the morning orbit was abandoned. The sampling of the diurnal cycle can be improved, for example, by using two orthogonal 90° inclined orbits which give both global coverage, and a statistical sampling of the full diurnal cycle at seasonal time scale. For understanding the radiative forcing – e.g. aerosol radiative forcing - and climate feedback – e.g. ice albedo feedback - mechanisms underlying changes in the EEI, and for climate model validation, it is necessary to separate the Total Outgoing Radiation (TOR) spectrally into the two components of the Earth Radiation Budget (ERB), namely the Reflected Solar radiation (RSR) and Outgoing Longwave Radiation (OLR) and to map them at relatively high spatial resolution. The Earth Climate Observatory (ECO) mission concept was recently selected by the European Space Agency as one of the 4 candidate Earth Explorer 12 missions, that will be further studied in Phase 0 until mid 2026. The current paper provides a broad overview of the ECO mission objectives, the mission requirements, and the key elements of a baseline mission concept. During Phase 0, the ECO mission concept will be further elaborated in two parallel industrial studies, which may or may not adopt or refine the elements of the baseline concept.
How to cite: Dewitte, S., Mauritsen, T., Meyssignac, B., August, T., Schifano, L., Smeesters, L., Roca, R., Brindley, H., Russell, J., Clerbaux, N., Hollmann, R., Megner, L., Haberreiter, M., Gumbel, J., Marotzke, J., Riedi, J., Riihela, A., Trent, T., and Wendisch, M.: The Earth Climate Observatory space mission concept for the monitoring of the Earth Energy Imbalance., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12847, https://doi.org/10.5194/egusphere-egu25-12847, 2025.
The Earth’s radiation budget is a crucial part of climate and its evolution. Being part of this budget, the outgoing longwave radiation (OLR) has been extensively studied, especially in the context of climate-change and anthropogenic greenhouse gases emissions modifying the Earth’s radiative equilibrium.
In this study we present a new line-by-line radiative code RadForcE, we have developed to compute the global OLR and radiative forcing over a 10-year period. Based on a backward longwave Monte Carlo method, RadForcE uses line-by-line spectroscopic data for several molecular gases (CO2, H2O, CH4 and O3) from high-resolution databases GEISA and HITRAN, as well as different continua. The clouds’ vertical distributions are taken into account with a vertical overlap subgrid parameterization that is sampled "on the fly" for each optical path along vertical atmospheric profiles. Those profiles are sampled over a 10-year period all over the globe, either from GCM outputs or from ERA5 reanalysis, to compute the unbiased global OLR at a very small computational cost (~10 minutes on a laptop).
We this new method we are also able to directly compute any greenhouse gas radiative forcing, and present estimates of the radiative forcing for a doubling of CO2. The Monte Carlo approach allows us to identify, for each outgoing optical path at the top of the atmosphere, the emitting species as well as the altitude of emission. By doing so, we can visualize the profile of altitude of emission for each species, as well as how some gases can screen other species’ emission or the surface’s emission. We can also visualize, for a doubling of CO2, the increase of stratospheric emission by CO2, and its screening of the surface’s emission and water vapor tropospheric emission.
How to cite: Jean-Louis, D., Raphaël, L., Yaniss, N.-P., Richard, F., and Stéphane, B.: Using line-by-line Monte Carlo to compute the Earth’s outgoing longwave radiation and CO2’s radiative forcing, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16594, https://doi.org/10.5194/egusphere-egu25-16594, 2025.
Upper tropospheric humidity (UTH) is a diagnostic of the atmospheric water cycle and strongly contributes to climate sensitivity. Therefore, it is important to understand UTH variability and how this is represented by global climate models. Here, infrared and microwave brightness temperature observations and satellite simulations based on ECMWF Reanalysis v5 (ERA5) and the Hadley Centre Global Environment Model version 3 (HadGEM3) Atmospheric Model Intercomparison Project (AMIP) data are used to evaluate and characterise UTH variability since 1979. UTH satellite observations have been simulated using a radiative transfer code (RTTOV) from ERA5 and HadGEM3 to provide a more direct comparison of the model and reanalysis to observations.
We present results on the sensitivities of water vapour brightness temperatures. There are competing influences of temperature and specific humidity on the brightness temperatures. The effect of these is such that fluctuations can be considered as a proxy for relative humidity. Despite this, a spurious increase in UTH of up to 1% is identified for a 1K increase in profile temperature when relative humidity remains constant.
We also investigate trends and variability of UTH. Using Principal Component Analysis, we explore the spatial and temporal impact of El Niño Southern Oscillation (ENSO) on UTH distribution and link this to changes in outgoing longwave radiation (OLR). Trends show increased UTH over the Indian Ocean and decreases over the western Pacific. This mirrors large-scale dynamic changes in the Walker Circulation, which shows a weakening of the circulation over the same period.
How to cite: Stevens, T., Allan, R., Hegglin, M., Bodas-Salcedo, A., and John, V.: Investigating trends, variability in observed and simulated upper tropospheric humidity and outgoing longwave radiation, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4221, https://doi.org/10.5194/egusphere-egu25-4221, 2025.
Water vapour (WV) is one of the most significant greenhouse gases and plays a critical role in the majority of the thermodynamic processes that occur within the atmosphere. Thus, it significantly influences the radiative budget and cloud formation mechanisms, being of paramount importance in weather forecasting. Therefore, accurate and detailed characterisation of its spatial and temporal distribution is of undoubtedly great interest. However, measurement techniques often struggle with its variability both in space and time, making it challenging to obtain regular and reliable measurements.
Although high resolution height-resolved profiles of water vapour mixing ratio are currently being acquired by lidar systems and providing powerful information, such instruments usually suffer from overlap issues in the lower hundred meters, precisely where greater concentrations of water vapour appear. This issue, together with the reduced global representativity due to the scarce number of operative lidar systems, hinders the use of this technique for continuous monitoring of water vapour near the ground. In contrast, other passive and active remote sensing techniques like Microwave Radiometers (MWR), Sun Photometers (SP) or Global Navigation Satellite System (GNSS) are well established and have been globally proven as a feasible and trustworthy alternative for continuous measurements of the total vertical column water vapour concentration (IWV).
This study addresses the characterisation of IWV over Granada, a city in southern Spain, using remote sensing techniques (MWR, SP and GNSS). These techniques are first validated against in situ data collected from over 70 radiosondes (RS). The study then investigates the IWV evolution over Granada for a 14-year period. The daily, seasonal and annual cycles are described together with the statistical behaviour of the data series in search of tendency changes.
Reanalysis data from Numerical Weather Prediction (NWP) models such as MERRA-2 (Modern-Era Retrospective Analysis for Research and Applications, version 2) and ERA5 (fifth generation of European Centre for Medium-Range Weather Forecasts reanalysis) are also validated against remote sensing measurements and then considered to expand the study period to more than 40 years, allowing the climatological study of water vapour in the area. Seasonal decomposition and a Mann-Kendall statistical test discovered an increasing tendency in IWV. Analogous analysis for the temperature in the region also found a positive increase, accentuated since the beginning of the 21st century and reinforcing the results of climate change studies. The relationship between both magnitudes indicates a possible contribution of increased water vapour concentrations to the observed increased temperatures.
How to cite: Naval Hernández, V. M., del Águila Pérez, A., Díaz Zurita, A., Rodríguez Navarro, O., Muñiz Rosado, J., Pérez Ramírez, D., Neil Whiteman, D., Alados Arboledas, L., and Navas Guzmán, F.: Long-Term Integrated Water Vapour (IWV) analysis in Southern Spain using remote sensing techniques and reanalysis models, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12571, https://doi.org/10.5194/egusphere-egu25-12571, 2025.
Many trace gases throughout Earth’s atmosphere are known to have a large potential to impact the radiation budget. The HITRAN database provides spectroscopic parameters and supplementary data in the form of line-by-line lists, absorption cross sections, collision induced absorption, water vapor continuum, and aerosol properties that enable molecular absorption to be modeled, which allows the radiation budget and radiative forcing to be determined. For HITRAN2024, in addition to increasing the number of molecules with line-by-line lists to 61, the absorption cross sections are receiving a substantial update. The update of cross sections makes use of many newly available experimental data and results in the addition over 100 molecules to the large number of molecules already represented as absorption cross sections in HITRAN2020 (Gordon et al. 2022). The absorption cross section update will also expand the range of experimental conditions available (i.e., temperatures, pressures, broadening gases, and resolutions) for many molecules that are present in Earth’s atmosphere. The new cross-sections have been a subjected to a validation process prior to being added to the database. This talk will showcase the absorption cross sections in HITRAN, and will highlight major updates for the 2024 compilation.
Funding from NASA grant 80NSSC23K1596 is acknowledged.
Reference: Gordon, et al., JQSRT 277, 107949 (2022). https://doi.org/10.1016/j.jqsrt.2021.107949
How to cite: Hargreaves, R., Gordon, I., Hill, C., Kochanov, R., and Rothman, L.: Updating the experimental absorption cross sections for HITRAN2024, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20646, https://doi.org/10.5194/egusphere-egu25-20646, 2025.
Aerosol-cloud-interactions (ACI) is a leading uncertainty in estimates of their radiative forcing and hence for climate projection. The aerosol radiative forcing obtained from climate models is poorly constrained by observations, because the ACI signal is frequently entangled with noise of meteorological co-variability.
The Iceland-Holuhraun volcanic eruption in Iceland in 2014 provided an unprecedented opportunity to examine ACI of marine low-level clouds and how well they are represented in climate models. Malavelle et al. (2017) used Collection 5 data from the MODIS Aqua satellite and provided an assessment of the impact of the large release of sulfur dioxide on cloud effective radius (reff) and cloud liquid water path (LWP), finding a considerable impact on the former, but no impact on the latter. We revisit this eruption with a considerably extended satellite record which includes new Collection 6 data from the Terra and Aqua satellite and additional years of data from 2015-2020. This tripling of satellite data allows using novel data-science approach for a more rigorous assessment of ACI, including the impacts not just on cloud micro-physical properties (reff and LWP), but also on the macro property cloud coverage (Chen et al., 2022).
These results show that cloud fraction is significantly increased by 10% and appears to surpass cloud brightening and to be the dominant factor in aerosol indirect radiative cooling. The ACI cooling effect via increasing of cloud cover is even more remarkable in tropics (Fig.1, upto 50%), as demonstrated by our recent study of Hawaii volcanic natural experiments (Chen et al., 2024). Climate models are unable to replicate such strong impacts on cloud cover. These results show that the ongoing debate about the cooling impact of aerosols is far from over while climate models continue to inadequately represent the complex macro- and micro-physical impacts of ACI. These researches point towards a direction and provide new constraints for improving model representation of ACI.
Figure 1. Aerosol-induced changes in cloud cover from volcano natural experiments. Source: Chen et al., (2024)
References:
Chen, Y., Haywood, J., Wang, Y., Malavelle, F., Jordan, G., Partridge, D., Fieldsend, J., De Leeuw, J., Schmidt, A., Cho, N., Oreopoulos, L., Platnick, S., Grosvenor, D., Field, P., and Lohmann, U.: Machine learning reveals climate forcing from aerosols is dominated by increased cloud cover, Nature Geoscience, 10.1038/s41561-022-00991-6, 2022.
Chen, Y., Haywood, J., Wang, Y., Malavelle, F., Jordan, G., Peace, A., Partridge, D. G., Cho, N., Oreopoulos, L., Grosvenor, D., Field, P., Allan, R., and Lohmann, U.: Substantial cooling effect from aerosol-induced increase in tropical marine cloud cover, Nature Geoscience, https://doi.org/10.1038/s41561-024-01427-z, 2024.
Malavelle, F., Haywood, J., Jones, A. et al. Strong constraints on aerosol–cloud interactions from volcanic eruptions. Nature 546, 485–491 (2017). https://doi.org/10.1038/nature22974
How to cite: Chen, Y., Haywood, J., Wang, Y., Malavelle, F., Jordan, G., Peace, A., Partridge, D., Cho, N., Oreopoulos, L., Grosvenor, D., Field, P., Allan, R., and Lohmann, U.: Observational evidence of strong aerosol fingerprints on clouds and effect on radiative forcing, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-27, https://doi.org/10.5194/egusphere-egu25-27, 2025.
Ozone is the third most important greenhouse gas, contributing a forcing of 0.47 W/m2 over the historical period. All assessments of ozone forcing so far have used the stratospheric-temperature adjusted radiative forcing (SARF) calculated by offline radiative transfer models. The two most recent IPCC reports have recommended the use of effective radiative forcing (ERF) as the preferred measure of forcing, but no calculations have been available.
For the first time we calculate the future ozone online ERF from six Earth system models and compare this to the SARF calculations. The future ozone calculations are for the SSP3-7.0 scenario for the year 2050. Only the ozone changes (and any consequent impacts on meteorology) are included in the radiative forcing calculations. We find an ERF of 0.27+/- 0.09 Wm-2 and an ozone column increase of 12 DU. Approximately half of the forcing change comes from ozone recovery following the decline in halocarbons.
By decomposing the radiative forcing into instantaneous (IRF), stratospheric-temperature adjusted (SARF) and effective (ERF) radiative forcing we gain insights into the adjustment processes causing the differences between the radiative forcing measures. The ERF is typically larger than the SARF. This is mostly due to positive non-cloud adjustments through increased water vapour (particularly in the stratosphere) and decreased surface albedo. Reductions in high and mid-level cloud increase the short-wave forcing, but decrease the long-wave forcing. The adjustments to the forcing depend on the altitude of the ozone change, with adjustments to ozone changes following reductions in ozone-depleting substances being more strongly positive than those following increases in ozone precursors.
How to cite: Collins, W., O'Connor, F., Byrom, R., Hodnebrog, Ø., Jöckel, P., Mertens, M., Myhre, G., Nützel, M., Olivié, D., Skeie, R., Stecher, L., Horowitz, L., Naik, V., and Murray, L.: Comparing radiative forcing measures for ozone, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11349, https://doi.org/10.5194/egusphere-egu25-11349, 2025.
Brown carbon (BrC) influences atmospheric radiative forcing through its unique light-absorption characteristics. The role of BrC as a significant absorbing component of organic aerosols (OA) has profound implications for understanding its impact on climate systems. However, the complex processes forming BrC, along with the chemical and optical properties that determine its behavior are not yet fully understood. These challenges are compounded by the fact that BrC's sources, formation processes, and interactions with other atmospheric components remain partially unknown.
Existing approaches to represent BrC in climate models range from intermediate schemes that explicitly account for its emission and aging to simplified methods that assume constant weak absorbing properties in OA. Furthermore, studies indicate that BrC may impose a radiative burden comparable to black carbon (BC), potentially amplifying the overall forcing exerted by carbonaceous aerosols.
However, it is not entirely clear how brown carbon contributes to atmospheric radiation and what role it plays in climate. Previous studies have offered varying estimates of BrC direct radiative effect (DRE), underscoring the need for refined modeling and observational data to understand BrC's role in atmospheric dynamics and its contribution to global warming. Here, we examined the global radiative impacts of anthropogenic BrC emissions using the EC-Earth3 Earth System Model. This study aims to address the significant uncertainties in climate modeling by enhancing the representation of BrC in models. This includes incorporating additional sources to provide more accurate estimations of its radiative effects. Furthermore, the study will assess the role of BrC in driving regional climate variations and their potential contributions to global climate forcing. For the BrC emissions, we used the ECLIPSE (Evaluating the Climate and Air Quality Impacts of Short-lived Pollutants) dataset, developed by the Finnish Environment Institute. Also, we used the Organic Carbon (OC) and BC emissions from the ECLIPSE emission dataset. EC-Earth3 simulations were conducted across different years to represent both historical and future scenarios. Each simulation was run for six years, including a one-year spin-up period.
Our preliminary results from historical simulations for the year 2010 indicate that the global mean direct radiative forcing of anthropogenic BrC emissions is negligible. However, regional effects are significantly more pronounced, which need to be studied further.
How to cite: Deshmukh, A., Laakso, A., Mielonen, T., Gkouvousis, A., Arola, A., Kokkola, H., and Bergman, T.: Radiative forcing of anthropogenic Brown Carbon in EC-Earth3, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19921, https://doi.org/10.5194/egusphere-egu25-19921, 2025.
How to cite: Gao, C. and Gao, Y.: Dwindling Effective Radiative Forcing of Large Volcanic Eruption: The Compensation Role of Ocean Latent Heat Flux, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1674, https://doi.org/10.5194/egusphere-egu25-1674, 2025.
This study investigates the impact of dust on radiation over the Arabian Peninsula (AP) during the reported high, low, and normal dust seasons (March-August) of 2012, 2014, and 2015, respectively. Simulations were performed using the Weather Research and Forecasting model coupled to a Chemistry module (WRF‐Chem). The simulated seasonal horizontal and vertical dust concentrations, and their interannual distinctions, match well with those from two ground‐based AERONET observations, and measurements from MODIS and CALIOP satellites. The maximum dust concentrations over the dust‐source regions in the southern AP reach vertically up to 700 hPa during the high dust season, but only up to 900– 950 hPa during the low/normal dust seasons. Stronger incoming low‐level winds along the southern Red Sea and those from Iraq bring in higher‐than‐normal dust during the high-dust summers. We conducted a sensitivity experiment by switching off the dust module to assess the radiative perturbations due to dust. The results suggest that active dust‐module improved the fidelity of simulated radiation fluxes distributions at the surface and top of the atmosphere vis‐à‐vis Clouds and the Earth's Radiant Energy System (CERES) measurements. Dust results in a 26 Wm− 2 short‐wave (SW) radiative forcing in the tropospheric column over the AP. The SW radiative forcing increases by another 6–8 Wm− 2 during the high dust season due to the increased number of extreme dust days, which also amplifies atmospheric heating. During extreme dust days, the heating rate exhibits a dipolar structure, with cooling over the Iraq region and warming of 40%–60% over the southern‐AP.
How to cite: Karumuri, R. K., Dasari, H. P., Gandham, H., Kunchala, R. K., Attada, R., Karumuri, A., and Hoteit, I.: Investigation of Dust‐Induced Direct Radiative Forcing Over the Arabian Peninsula Based on High‐Resolution WRF‐Chem Simulations, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1626, https://doi.org/10.5194/egusphere-egu25-1626, 2025.
The Earth's radiation budget is a fundamental determinant of climate dynamics, serving as the primary energy source for the planet and influencing its climate system's evolution. Aerosols, as a climate forcer, modify the distribution of solar radiation in the atmosphere and reduce the radiation reaching the Earth's surface.
The Weather Research and Forecasting model coupled with Chemistry (WRF-Chem) is actively used in operational air quality forecasting systems across the globe. Previous studies have shown that the model has limited success in predicting the air quality over the Indian national capital, New Delhi, especially when the Air Quality Index is in ‘Severe’ conditions during the winter months. It has been reported that the model depicts a mean bias of ~ 34 Wm-2 in downward shortwave radiation (SWDOWN) flux reaching the surface which may have led to overestimated near-surface temperature (~3.18 ⁰C). This warm bias in temperature might lead to a greater vertical dispersion of the near-surface pollutants, leading to an underestimation of air quality close to the surface. Such biases in the SWDOWN can be due to inadequate information of optical properties of aerosols in the model.
This study aims to address this gap by incorporating realistic complex refractive indices of aerosol species into WRF-Chem simulations over the ambient environment of Delhi. Five sensitivity experiments (EXP) were conducted, focusing on the impact of aerosol optical properties on the radiative fluxes during the winter season of 2023-24. The results demonstrate that altering a single aerosol optical parameter leads to a reduction in surface shortwave radiation flux by 28–30 Wm⁻² during October and November, and 25 Wm⁻² during December and January, relative to control simulations. Model outputs, validated against observational data, indicate a reduction in the mean bias of SWDOWN by 12.99 Wm⁻² and 17.24 Wm⁻² in December and January, respectively. These results underscore the significant role of aerosol optical properties in modulating radiative fluxes and their implications for the surface energy budget.
The study also examines the impacts of modified radiation parameterization on the model-simulated aerosol fields like the near-surface PM2.5 concentration using ground-based measurements and the Aerosol Optical Depth (AOD) over the region as space-based measurements from instruments like MODerate resolution and Imaging Spectroradiometer (MODIS) onboard the TERRA and AQUA satellites. Preliminary findings, revealing the impact of radiation bias on the simulation of meteorological variables and subsequent weather events, will be presented during the session of EGU 2025.
How to cite: Kumar, S., Govardhan, G., and Ghude, S.: Impact of Aerosol Optical Properties on Surface reaching Shortwave Radiation over Delhi in WRF-Chem, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-601, https://doi.org/10.5194/egusphere-egu25-601, 2025.
The land surface albedo is one of the key parameters of the global radiation budget, since it regulates the shortwave radiation absorbed by the Earth’s surface. The polar regions, in particular, a decrease in snow and ice cover results in a decrease of surface albedo and in the intensification of solar heating further reducing the snow and ice areas (ice-albedo feedback). In remote areas, where in-situ instruments are absent, satellites are crucial to measure surface albedo changes.
In this work, a comparison of satellite and in-situ measurements of broadband shortwave surface albedo is conducted. The area of interest selected is around the Thule High Arctic Atmospheric Observatory (THAAO) on the North-western coast of Greenland (76.5°N, 68.8°W), where the measurements of down-welling and up-welling shortwave irradiance have been started in 2009 and 2016, respectively (https://www.thuleatmos-it.it/).
Albedo determinations based on MODIS observations from both Terra and Aqua (MODIS MCD43A3 dataset), consisting of daily values with a spatial resolution of 500 m, have been compared with the ground-based measurements.
The analysis has been conducted for all-sky and clear-sky conditions with a focus on some events to better understand the behavior of MODIS data with respect to ground-based measurements, taking advantage of the additional information (meteorological parameters, cloudiness, precipitation) available at THAAO.
The results for the period 2016-2024 show an underestimation of the albedo measurements from satellite compared to the ground-based measurements at the THAAO over a large part of the period considered. The best agreement is found in the summer when there is no snow around the Observatory, and the mean measured albedo value is 0.1633 for cloud-free conditions and 0.1903 for all-sky conditions. The mean bias during this season is around -0.0074 for cloud-free conditions and 0.0067 for all sky conditions. In spring, when the in-situ albedo values are highly variable, between 0.350 and 1, the mean bias is around -0.0645 for cloud-free conditions and -0.0159 for all sky conditions.
The fast changes in surface albedo occurring after short snow precipitation or removal events are seldom captured by satellite observations.
How to cite: Tosco, M., Meloni, D., Calì Quaglia, F., Muscari, G., Di Iorio, T., Pace, G., Ciardini, V., and di Sarra, A. G.: Measurements of land surface albedo at the Thule High Arctic Atmospheric Observatory (THAAO) in Pituffik, Greenland and comparison with MODIS data., EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17123, https://doi.org/10.5194/egusphere-egu25-17123, 2025.
High-altitude regions are argued to react more strongly to global warming compared to low-altitude regions. However, due to a combination of feedback mechanisms, micro-climatic trends, and lack of long-term observational data, elevation-dependent warming has been difficult to understand and quantify. We address this question using a surface energy balance approach where 2m air temperature variations along altitudes are quantified following changes in surface radiation and turbulent fluxes. The turbulent fluxes in the energy balance are constrained using the thermodynamic limit of maximum power. The downwelling longwave radiation is parameterized using the semi-emperical equation by Brutsaert (1975). We used BSRN (Baseline Surface Radiation Network) and FLUXNET dataset to test our approach and found that daily variations in 2m air temperatures reasonably well (with R2 value of 0.75) along the altitude gradient. We find that for high altitudes, the downwelling longwave radiation is lesser compared to stations at low altitudes at similar latitudes for both all sky conditions and clear sky conditions. We attribute it to less absorptive mass above the high altitudinal setting, leading to lower atmospheric emissivity and changes in lower atmospheric heat storage. On the other hand, absorbed solar radiation when normalized by potential solar radiation, shows strong seasonality, which is influenced by albedo changes and water vapor content in the atmosphere. Future work entails extending this framework to get a physically based estimate of elevation-dependent warming using the sensitivity of temperature to components in the energy balance. This understanding is crucial for anticipating the impacts of warming on water resources and ecosystems in these regions and, consequently, for developing effective adaptation and mitigation strategies.
How to cite: Shukla, S., Kleidon, A., Ghausi, S. A., and Chauhan, T. A.: Understanding altitudinal temperature variations using a surface energy balance approach , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11477, https://doi.org/10.5194/egusphere-egu25-11477, 2025.
The land subsurface stored around a 6 % of the Earth’s energy imbalance in the last decades, being the second contributor to the partitioning after the ocean (90 %). Previous studies have shown that state-of-the-art Earth System Models (ESMs) remarkably underestimate the observational land heat uptake values. This underestimation stems from Land Surface Models (LSMs) within ESMs imposing too shallow zero-flux bottom boundary conditions to correctly represent the conductive propagation and land heat uptake with depth. However, non-significant temperature variability differences at the ground surface have been detected when these boundary conditions are prescribed deeper, so the physical process limiting land heat uptake was not yet identified. This study reveals that the underlying mechanism is the reduced incoming ground heat flux (GHF). To conclude this, GHF values coming from an ensemble of eight historical and RCP8.5 land-only simulations with different subsurface depths conducted with the LSM of the Max Planck Institute for Meteorology ESM (MPI-ESM), JSBACH, have been compared to GHF estimates yielded by a one-dimensional heat conduction forward model. Results show that GHF doubles when deepening the LSM from 10 to 25 m, saturating at a factor of 5 when the boundary condition is placed at approx. 100 m. The increase in the incoming GHF is mainly compensated by a global increase in the outgoing sensible heat flux (SHF), a small increase of the latent heat flux (LHF) in wet regions, and an increase in the surface net radiation in arid and semi-arid regions.
How to cite: García-Pereira, F., González-Rouco, J. F., Meabe-Yanguas, N., Jungclaus, J., de Vrese, P., and Lorenz, S.: An insufficient subsurface depth biases the long-term surface energy balance in Land Surface Models , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13806, https://doi.org/10.5194/egusphere-egu25-13806, 2025.
Wild (2020), and Wild and Bosilovich (2024) provide estimates of global mean energy balance components as represented in climate models and reanalyses, with reference estimates from Loeb et al. (2018), Wild et al. (2015, 2019), L’Ecuyer et al. (2015) and Kato et al. (2018). Here we add a theoretical reference estimate (TRE) based on four radiative transfer equations and geometric considerations as detailed in Zagoni (2025). The equations do not refer to the atmospheric gaseous composition or the reflective properties of the surface or clouds. The first equation is a clear-sky constraint relationship on the net radiation at the surface (RN), following from the two-stream approximation of Schwarzschild’s (1906-Eq.11) radiative transfer equation as given in standard university textbooks on atmospheric physics and radiation (Goody, Oxford, 1964_Eq.2.115; Houghton, Cambridge, 1977_Eq.2.13; Hartmann, Academic Press 1994, Eqs. 3.51-3.54; Ambaum, RoyalMetSoc, 2021_Eq.10.56), and in university lecture notes (Stephens 2003): RN=OLR/2. The second equation is a clear-sky constraint relationship on the total radiation at the surface (RT), following from the simplest greenhouse geometry (Hartmann 1994, Fig.2.3): RT=2OLR. The third and fourth equations are all-sky versions of the first pair: RN(all-sky)= (OLR–LWCRE)/2, and RT(all-sky)=2OLR+LWCRE. Two decades of CERES observations (EBAF Ed4.1 April 2000–March 2022) give –2.33, –2.82, 2.71 and 2.44 [Wm-2] deviations for the four equations, respectively, with a mean difference of 0.00. The all-sky equations are justified by an independent estimate of GEWEX within 0.1 Wm-2 (Zagoni 2024). The solution can be given in small integer ratios relative to LWCRE as the unit flux; the best fit is 1 unit = 26.68 Wm-2, see Table1 (highres figures and other info about TRE available at TABLELINK). Some of the most remarkable precisions are in TOA SW up all-sky (=100) and clear-sky (=53). — Li, Li, Wild and Jones (2024) provide a global radiation budget from a surface perspective from 34 CMIP6 models for 2000-2022, with differences from the TRE integer positions less than 1 Wm-2 in SW down radiation, Thermal down Surface and the convective flux (Sensible heat + Latent heat); less than 2 Wm-2 in Thermal up Surface; and less than 3 Wm-2 in Reflect by surface; each within the noted ranges of uncertainty. Stackhouse et al. (2024) give Earth radiation budget at top-of-atmosphere; TRE differ from 2001-22 Climatological Mean in OLR, TSI and RSW by 0.23, 0.03 and 1.05 [Wm-2], see details in TABLELINK in References.
References
Li, X., Li, Q., Wild, M. and Jones, P. (2024) An intensification of surface EEI. NatureCommE&E, https://www.nature.com/articles/s43247-024-01802-z
Stackhouse, P., et al. (2024) State of the Climate 2023, Bull. Am. Met. Soc. 105:8, https://journals.ametsoc.org/view/journals/bams/105/8/2024BAMSStateoftheClimate.1.xml
Stephens, G. (2003) Colorado_State_University_AT622_Section 6_Eqs. (6.10a)-(6.10b), Example 6.3, Fig. 6.3a, https://reef.atmos.colostate.edu/~odell/AT622/stephens_notes/AT622_section06.pdf
Wild, M. (2020) The global energy balance as represented in CMIP6 climate models. Climate Dynamics 55:553–577, https://doi.org/10.1007/s00382-020-05282-7
Wild, M., Bosilovich, M. (2024) The global energy balance as represented in reanalyses. Surv Geophys, https://link.springer.com/article/10.1007/s10712-024-09861-9
Zagoni, M. (2024) Modeling and Observing Global Energy and Water Cycles by GEWEX. AGU Fall Meeting, https://agu.confex.com/agu/agu24/meetingapp.cgi/Paper/1535956
Zagoni, M. (2025) Trenberth’s Greenhouse Geometry. AMS Annual Meeting, https://ams.confex.com/ams/105ANNUAL/meetingapp.cgi/Paper/445222 see also the updated Supplementary Material video: https://www.earthenergyflows.com/Zagoni-EGU2024-Trenberths-Greenhouse-Geometry_Full-v03-480.mp4
TABLELINK: https://earthenergyflows.com/TRE20.pdf
How to cite: Zagoni, M.: Theoretical reference estimate for the components of the global energy balance, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1, https://doi.org/10.5194/egusphere-egu25-1, 2025.
Understanding the long-term changes in the global water vapor content is critical for assessing natural vs. human-caused climate change. Despite the strong thermodynamical relationship between temperature and water vapor changes, substantial discrepancies still exist between observations, reanalysis products, and climate model simulations.
In this work, we assess the consistencies and discrepancies of total column water vapor (TCWV) estimates between three observational techniques and three reanalysis products. The observations include satellite-borne microwave radiometers (MWR) over the oceans, GPS–Radio Occultation (GPS-RO) observations from low-orbiting satellites over both ocean and land, and ground-based GNSS receivers over land and on islands. The three reanalyses are ERA5, MERRA-2, and JRA-55. They all assimilate radiances from the satellite microwave radiometers and bending angles produced from GPS-RO measurements. Ground-based GNSS measurements are not assimilated and serve as a fully independent validating data set.
We examine the overall agreement in global TCWV trends in the different data sets over the period from 1980 to the present. We highlight strong features of global climate variability such as the El-Niño Southern Oscillation (ENSO). We focus on the past few years which were characterized by a persistent strong La Niña period (2020-2022), followed by a strong El Niño event (2023/2024). Both ENSO phases had a tremendous impact on regional climate extremes, leading to extended heat waves and wildfires or heavy precipitation and flooding in many places around the world.
How to cite: Bock, O., Mears, C., Ho, S.-P., and Shao, X.: Changes in global water vapor from observations and reanalysis products, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8237, https://doi.org/10.5194/egusphere-egu25-8237, 2025.
Earth's energy budget defines the balance between the incoming radiant solar energy reaching Earth and the energy returning to outer space. Clouds play a significant role in Earth's energy budget. Cloud Radiative Forcing (CRF) is the difference between the radiative fluxes at the top of the atmosphere in clear-sky and all-sky conditions. Clouds introduce two contrasting effects on the Earth's energy balance: the albedo effect and the longwave effect. Clouds reflect a large amount of incoming shortwave radiation and cool the Earth, known as the Albedo effect. The energy associated with the albedo effect is known as shortwave cloud radiative forcing (SWCRF). The longwave effect or longwave cloud radiative forcing (LWCRF) denotes the warming of Earth by the cloud-trapped longwave radiation that would otherwise escape to space. Understanding the variability in the amount and distribution of clouds in a warming climate is essential as they modulate the shortwave and longwave cloud radiative feedbacks (Harrison et al., 1990; Bony, S. et al., 2006) and, thereby, the Net CRF. Upper Tropospheric Humidity (UTH) is a vital climate variable that impacts the amount of outgoing longwave radiation. In the tropics, UTH is mainly driven by deep convection. The present study analyzes the influence of UTH on the longwave cloud radiative forcing in the tropics from 2000 to 2021. This study uses the satellite microwave (MW) and infrared (IR) UTH measurements. Clouds affect IR UTH measurements, while MW measurements provide UTH under all sky conditions. Clouds and the Earth's Radiant Energy System (CERES) satellite datasets are used to calculate cloud radiative forcing. This study quantifies the UTH-LWCRF relationship and shows that UTH can explain LWCRF variability in the tropics to a large extent. The joint distribution analysis shows that UTH has a significant impact on the variability of LWCRF over land, whereas over ocean regions, sea surface temperature plays a role in modulating the UTH-LWCRF relationship. Also, the UTH-LWCRF relationship is better represented with MW UTH than IR UTH, which can be attributed to the more comprehensive and accurate MW measurements even in cloudy conditions.
How to cite: Moovidathu Vasudevan, D., Kottayil, A., and O John, V.: Upper Tropospheric Humidity and Cloud Radiative Forcing: A Tropical Perspective, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-849, https://doi.org/10.5194/egusphere-egu25-849, 2025.
The representation of the global mean energy balance components in 10 atmospheric reanalyses is assessed and compared with recent reference estimates as well as the ones simulated by the latest generation of climate models from the 6th phase of the coupled model intercomparison project (CMIP6). Despite the assimilation of comprehensive observational data in reanalyses, the spread amongst the magnitudes of their global energy balance components generally remains substantial, up to more than 20 Wm-2 in some quantities, and their consistency is typically not higher than amongst the much less observationally constrained CMIP6 models. Relative spreads are particularly large in the reanalysis global mean latent heat fluxes (exceeding 20%) and associated representation of the intensity of the global water cycle, as well as in the energy imbalances at the Top-of-Atmosphere and surface. A comparison of reanalysis runs in full assimilation mode with corresponding runs constrained only by sea surface temperatures reveals marginal differences in their global mean energy balance components. This indicates that discrepancies in the global energy balance components caused by the different model formulations amongst the reanalyses are hardly alleviated by the imposed observational constraints from the assimilation process. Similar to climate models, reanalyses overestimate the global mean surface downward shortwave radiation and underestimate the surface downward longwave radiation by 3 - 7 Wm-2. While reanalyses are of tremendous value as references for many atmospheric parameters, they currently may not be suited to serve as references for the magnitudes of the global mean energy balance components.
Published as:
Wild, M., and Bosilovich, M., 2024: The Global Energy Balance as Represented in Atmospheric Reanalyses, Surveys in Geophysics, 45, 1799–1825. https://doi.org/10.1007/s10712-024-09861-9
How to cite: Wild, M. and Bosilovich, M.: The Global Energy Balance as represented in Atmospheric Reanalyses, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2516, https://doi.org/10.5194/egusphere-egu25-2516, 2025.
NASA projects that provide estimates of solar irradiance in the context of meteorological conditions (i.e., clouds, aerosols and gaseous constituents, etc.) spanning from 1983 to near present (i.e., Surface Radiation Budget (GEWEX SRB), Clouds and Earth’s Radiance Energy System – CERES and Modern Era Reanalysis-assimilation for Research and Applications – MERRA2, etc.). Those data products provide nearly 40 years of covariant information from global to regional scales. These records provide the opportunity to assess the decadal variability of these fluxes with the capability to attribute changes to various cloud and/or aerosol processes. Utilizing these observations, we assess the long-term projections of the surface solar fluxes from CMIP6 model runs utilizing NASA’s Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) data set (Thrasher et al., 2023) for three socio-economic pathways utilized by Climate Modeling Intercomparison Project (CMIP6) that span from 1950 to 2100 and includes projections of temperature and solar irradiance with 7 other parameters. Over the Continental United States, we find that the data products used to downscale this NEX-GDDP needs to be re-evaluated but that the long-term changes in surface solar fluxes show very little trend. However, the 2-4 decade variability is larger by as much as a factor of 4. This has implications in terms of surface energy flux exchange at the surface and even for assessing the solar availability for solar power resources
How to cite: Stackhouse, P., Khadka, N., Hegyi, B., Cox, S., Mikovitz, J. C., and Zhang, T.: Using Decadal Variability of Surface and Satellite-based Measurements of Surface Solar Fluxes to Assess Current and Long-term Projected Changes from CMIP-6 , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20374, https://doi.org/10.5194/egusphere-egu25-20374, 2025.
Comparing with observations, the abnormally smaller cloud absorption (to solar radiation) given by climate models (namely alleged cloud absorption anomaly) ever raised widespread concerns in the mid-1990s and early 2000s but was seldom mentioned thereafter. Based on three state-of-the-art modeled products, NCEP CFSv2, ECMWF ERA5 and NASA MERRA2, and the newest collocated satellite-surface observation in the last 12 years (2012–2023), we reinvestigate this controversial issue. Our results demonstrate the observed cloud absorption of solar radiation still significantly exceeds the modeled (regardless of modeled products), but their systematic discrepancy has dropped a lot, especially for NCEP CFSv2. NCEP CFSv2 has the lowest bias with the observation, followed by ECMWF ERA5, and the bias of NASA MERRA2 is largest. This implies that cloud absorption anomaly fluctuates with not only sites (as reported by previous studies) but also models. Models’ radiation schemes that introduce the Monte Carlo Independent Column Approximation (McICA) may mitigate the systematic discrepancy between observation and modeling essentially. Additionally, it is noteworthy that there is not a perfect approach to obtaining the observed cloud absorption and particularly the water vapor difference between clear and cloudy skies often would result in its unrealistic overestimation. If the influence from the water vapor difference is neglected, NCEP CFSv2, ECMWF ERA5 and NASA MERRA2 underestimate globally-mean cloud absorption by approximately 10.07 W/m2, 16.65 W/m2 and 18.67 W/m2, respectively; and if it is corrected, the underestimations will be reduced to 7.75 W/m2, 14.33 W/m2 and 16.35 W/m2, respectively.
How to cite: Huang, G.: Is the cloud absorption of solar radiation still underestimated significantly by current climate models?, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5356, https://doi.org/10.5194/egusphere-egu25-5356, 2025.
Efficiently delivering large quantities of climate intervention material (CIM) to the stratosphere remains a technical challenge in stratospheric aerosol injection (SAI). A novel approach, solar-powered lofting (SPL), mimics the natural ascent of wildfire smoke, using small amounts of black carbon (BC) to transport SO2 from the troposphere to the stratosphere. The Asian Summer Monsoon(ASM) anticyclone over the Tibetan Plateau can also transport aerosols into the stratosphere, acting as a “chimney”. In this study, we investigate whether these two effcts, i.e. SPL effect and ASM “chimney effect”, combined together to deploy SAI will have better effect, by using a fully coupled Earth System Model.We select the Tibetan Plateau as the injection site for the Northern Hemisphere mid-latitudes, instead of the traditional Pacific location, and compare the differences in sulfate aerosol transport efficiency, distribution, and climate impacts. From 2040 to 2047 under the SSP5-85 emission scenario, ASM’s injection results in 20% more sulfur transported to the stratosphere and a 20% reduction in radiative forcing imbalance at mid-latitudes. Additionally, they lead to a 25% increase in both global annual average surface cooling and September Arcitc sea ice recovery.
How to cite: Lu, Y., Bian, J., and Li, D.: Asian Summer Monsoon Exacerbates the transport efficiency of Stratospheric Aerosol Injection, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5791, https://doi.org/10.5194/egusphere-egu25-5791, 2025.
Land-use change (LUC) is ranked as the second anthropogenic source of climate change after fossil fuel burning and yields negative albedo-induced radiative forcing (ARF). This cooling effect has been assessed using low spatiotemporally resolved LUC datasets derived from historical statistical data with large uncertainties. Herein, we implement a satellite remote sensing derived highly resolved LUC dataset into a compact earth system model and reassess the global and regional surface ARF by LUC from 1983 to 2010 relative to 1750. We find that the magnitude of negative ARF obtained from the present study is lower by 20% than that estimated by the Intergovernmental Panel on Climate Change, implying a weaker cooling effect. The result reveals that the global LUC-induced surface albedo change may not significantly slow down global warming as was previously anticipated. Sub-Saharan Africa made the largest net proportion to the magnitude of global ARF (39.2%), due to substantial land use conversions, typically the conversion from forest to other vegetation lands, which accompany with higher surface albedos. The most remarkable land cover changes occurred in East and Southeast Asia, which dominated the changes in global ARF in recent decades. Based on major land cover types in these two regions, we infer that vegetation lands exert a most vital effect on global ARF variation.
How to cite: Zhang, X.: Highly-resolved satellite remote sensing based land-use change inventory yields weaker surface albedo-induced global cooling, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8463, https://doi.org/10.5194/egusphere-egu25-8463, 2025.
Significant uncertainties remain in the estimate of radiative forcing (RF) induced by land-use change (LUC), partially attributable to the lack of reliable LUC data with a high spatiotemporal resolution. We implemented a high spatiotemporally resolved LUC data set in an earth system model (OSCAR) to examine the response of RF to LUC from 1982 to 2010 in China. Results were compared with the RF estimated using a low spatiotemporally resolved LUC inventory employed previously. The updated LUC data set reduces negative RF by −3.8% from 2000 to 2010 due to the changes in surface albedo subject to LU transition. The simulated mean RF driven by CO2 associated with LUC from 1982 to 2010 using a high spatiotemporally resolved LUC data set reached 0.074 W m−2, considerably higher than 0.022 W m−2 of mean RF derived from the low spatiotemporally resolved LUC inventory, implying increasing net RF and more substantial LUC induced warming.
How to cite: Jian, X.: The response of radiative forcing to high spatiotemporally resolved land-use change and transition from 1982 to 2010 in China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8471, https://doi.org/10.5194/egusphere-egu25-8471, 2025.
The Eurasia continent underwent significant winter cooling from 1998 to 2012, occurring within the context of global warming. This phenomenon has primarily been linked to internal variability, as previous research indicates; however, discussions regarding its underlying causes continue. Based on the simulations with both combined and individual external forcing, this study suggests that combined external radiative forcing accounts for approximately a quarter of the observed winter cooling in Europe from 1998 to 2012 by contributing to a negative North Atlantic oscillation. Among all individual external forcings, the influence of ozone, which includes the effects of solar cycle 23 from maximum to minimum, is most prominent.
How to cite: Suo, L., Bethke, I., Keenlyside, N., and Counillon, F.: External radiative forcing partly explains the Europe winter cooling in 1998-2012, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10498, https://doi.org/10.5194/egusphere-egu25-10498, 2025.
Almost all solar resource assessment and forecasting endeavors require gridded surface irradiance retrieved from geostationary satellites. China’s solar industry has hitherto been relying upon Himawari and Meteosat-derived surface irradiance products. Despite the maturity of those products, none provides a complete coverage of China, which implies a series of data issues, such as the inconsistency at product boundaries or limited resolution towards the edge of the field-of-view disks. However, data issues are but secondary, and the lack of autonomous capability of performing solar resourcing is what truly troubles those concerned. China’s latest geostationary weather satellite series, Fengyun-4 (FY-4), has the most advanced technology, but its service commenced only fairly recently in 2017. Hence, to meet China’s immediate needs for solar resources under its radical decarbonization target, which cannot afford to wait for FY-4 data to pile with time, soliciting information from its predecessor series, namely, FY-2, is thought to be apt. In this work, a high-resolution (1.25 km) satellite-derived surface irradiance product over a twelve-year period (2011–2022) is developed, based on the scanning radiometers onboard FY-2E, -2F, and -2G satellites. A series of analysis as to quantifying the interannual and spatial variability of solar irradiance in China, which has rarely been done before, confirm that the current product can suffice most solar resourcing applications.
How to cite: Shi, H.: China's autonomous solar energy products with the application of Fengyun satellites, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-14827, https://doi.org/10.5194/egusphere-egu25-14827, 2025.
The incoming surface solar radiation is an essential climate variable as defined by GCOS. Long term monitoring of this part of the earth’s energy budget is required to gain insights on the state and variability of the climate system. In addition, climate data sets of surface solar radiation have received increased attention over the recent years as an important source of information for solar energy assessments, for crop modeling, and for the validation of climate and weather models; all requiring high-quality and temporally-consistent data records.
It has been established in recent years, based on surface- and remote sensing-based data records, that surface irradiance has increased in many regions worldwide since the mid-1980, the so-called ‘global brightening’. The mechanisms behind this brightening, however, is not yet fully understood. It appears likely that changes in the atmospheric composition, mainly the aerosol loading, and possibly also atmospheric circulation have both been contributing to the global brightening.
Here we will use satellite-based data records from the CM SAF, SARAH and CLARA, which do not include an explicit treatment of the direct aerosol effect on clears-sky radiation to investigate the possible role of the aerosol on surface irradiance. Daily and monthly surface reference data (all-sky and clear-sky) are used to identify weaknesses in the satellite-based data records; aerosol information, e.g., from MERRA, are used to possibly explain these shortcomings, hence allowing to identify and to quantify the possible aerosol effect on surface irradiance.
How to cite: Trentmann, J., Pfeifroth, U., and Wild, M.: Assessing the direct aerosol impact on surface irradiance using satellite-based and surface reference data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-10896, https://doi.org/10.5194/egusphere-egu25-10896, 2025.
The burning of solid biomass fuel in traditional cooking stoves is still a major source of air pollution in India’s rural areas. Thereby estimates of source emissions becomes extremely important considering its effect on health and environment. The present study aims to measure and characterize aerosol emissions from the use of various single and mix-solid biomass fuels (fuelwood, dung cake, crop-residue) for cooking in traditional cookstoves. A portable versatile source sampling system (VS3) having PM2.5 samplers along with aethalometer (AE33) were taken on-field in Bihar and Haryana to capture real time emission measurement during cooking activity. A total of 84 experiments were conducted during both morning and evening cooking and the data was analysed to understand the impact of various fuel types, cooking processes and emission characteristics on black carbon (BC) @880nm. The burn rates in case of single fuel use like fuelwood, dung cake, and crop residue were found 1.6 ± 0.8, 1.56 ± 0.5, and 1.83 ± 0.9 kgh-1 respectively, however, in case of mix-fuel usage like firewood with dung cake and crop-residue was 2.4 ± 1.3 kgh-1. The relationship between combustion temperature and BC was investigated using the Pearson correlation test. The results revealed a weak (R2 = 0.124) but significant association, suggesting that while combustion temperature influences BC levels, other factors also play important roles. ANOVA tests were conducted to ascertain the statistical significance of the variations in BC emissions across different fuel types and cooking techniques. The tests revealed that both fuel types and cooking processes significantly affect BC concentrations (P-value~0). To delve deeper, regression analyses were performed, revealing that these factors account for approximately 10.3% of the variability in BC. The models highlighted the influence of specific fuel types and cooking processes, underscoring the complexity of factors impacting BC emissions. This multifaceted approach not only enhances our understanding of how cooking and combustion practices influence BC emissions but also underscores the importance of considering a variety of factors when developing strategies to reduce air pollution and improve environmental health. Understanding BC emissions can guide policies to improve energy access and reduce socioeconomic disparities. The paper will focus on looking other combustion parameters like atmospheric temperature and relative humidity and the impact of single and mix-fuel use on the BC emissions.
How to cite: Kumari, J. and Habib, G.: Black Carbon Emissions and Their Relation to Emission Characteristics from Traditional Cookstoves in Rural India, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20092, https://doi.org/10.5194/egusphere-egu25-20092, 2025.
