A5008093936- Atmospheric aerosols and clouds
- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Climate variability and models
- Atmospheric and Environmental Gas Dynamics
- Meteorological Phenomena and Simulations
- Aeolian processes and effects
- Air Quality Monitoring and Forecasting
- Solar Radiation and Photovoltaics
- Climate Change Policy and Economics
- Climate Change and Geoengineering
- Climate Change Communication and Perception
- Geophysics and Gravity Measurements
- Disaster Management and Resilience
- Marine and coastal ecosystems
- Solar and Space Plasma Dynamics
- Air Quality and Health Impacts
- Sustainability and Climate Change Governance
- Oceanographic and Atmospheric Processes
- International Development and Aid
- Geological Modeling and Analysis
- Tropical and Extratropical Cyclones Research
- Reservoir Engineering and Simulation Methods
- Tree-ring climate responses
- Oil, Gas, and Environmental Issues
Stockholm University
2016-2025
Bolin Centre for Climate Research
2014-2024
National Institute of Meteorology
2022-2024
Uganda National Meteorological Authority
2022-2024
Sabin Vaccine Institute
2024
University of California, San Diego
2011
University of California System
2011
Scripps Institution of Oceanography
2011
Significance The cooling effect of aerosols on climate and the modification clouds by have been widely debated, because quantifying their effects is important for constraining current change. Here we present measurements turbulence from unmanned aerial vehicles. We find that absorption sunlight black carbon (BC) suppresses in lower atmosphere, with consequences environmental impacts BC emissions anthropogenic fossil fuel biomass burning. A mechanism proposed links suppressed to taller...
Significance Enhancement of aerosol that can nucleate cloud droplets increases the droplet number concentration and albedo clouds. This amount sunlight reflected to space. Uncertainty in how aerosol−cloud interactions over industrial period have increased planetary by this mechanism leads significant uncertainty climate projections. Our work presents a method for observationally constraining change due anthropogenic emissions: hemispheric difference remotely sensed between pristine Southern...
Abstract Aerosol‐cloud interactions (ACI) represent a significant source of forcing uncertainty in global climate models (GCMs). Estimates radiative due to ACI Fifth Assessment Report range from −0.5 −2.5 W m −2 . A portion this is related the first indirect, or Twomey, effect whereby aerosols act as nuclei for cloud droplets condense upon. At constant liquid water content increases number (Nd) and thus albedo. In study we use remote‐sensing estimates Nd within stratocumulus regions...
Abstract. The liquid water path (LWP) adjustment due to aerosol–cloud interactions in marine stratocumulus remains a considerable source of uncertainty for climate sensitivity estimates. An unequivocal attribution LWP adjustments changes aerosol concentration from climatology difficult the covariance between meteorological conditions alongside concentrations. We utilise susceptibility framework quantify potential change with boundary layer (BL) depth subtropical stratocumulus. show that...
Abstract Contemporary general circulation models (GCMs) and Earth system (ESMs) are developed by a large number of modeling groups globally. They use wide range representations physical processes, allowing for structural (code) uncertainty to be partially quantified with multi‐model ensembles (MMEs). Many in the MMEs Coupled Model Intercomparison Project (CMIP) have common development history due sharing code schemes. This makes their projections statistically dependent introduces biases MME...
Abstract. The Next Generation of Earth Modeling Systems (nextGEMS) project aimed to produce multi-decadal climate simulations, for the first time, with resolved kilometer-scale (km-scale) processes in ocean, land, and atmosphere. In only three years, nextGEMS achieved this milestone two km-scale system models, ICOsahedral Non-hydrostatic model (ICON) Integrated Forecasting System coupled Finite-volumE Sea ice-Ocean Model (IFS-FESOM). was based on cornerstones: 1) developing models small...
It has been long understood that the partly cloudy atmosphere manifests a continuum of states between end members 'clear' and 'cloud.' Nevertheless, many research methods are premised on dichotomy states—for example, those use 'cloud cover' or 'cloud-clearing.' Here we consider consequences this practice for studies aerosolclimate effects. Aerosols affect Earth's energy budget primarily by affecting albedo; therefore, explore nature albedo variability in marine boundary layer scales down to...
Abstract. Cloud droplet number concentration (CDNC) is the key state variable that moderates relationship between aerosol and radiative forcing arising from aerosol–cloud interactions. Uncertainty related to effect of anthropogenic on cloud properties represents largest uncertainty in total forcing. Here we show regionally averaged time series Moderate-Resolution Imaging Spectroradiometer (MODIS) observed CDNC low, liquid-topped clouds well predicted by MERRA2 reanalysis near-surface sulfate...
Abstract Under the auspices of WCRP Grand challenge on Clouds, circulation and climate sensitivity, a selection experts have made an unprecedented effort to bound global radiative forcing by atmospheric aerosol, presented in Bellouin et al. (2019, https://doi.org/10.1029/2019RG000660 ). In addition updated interval, confirming progress field, main strength assessment is conceptual framework, that with clarity invites further range refinement. The sense conflict between process understanding...
Abstract A supervised neural network algorithm is used to categorize near‐global satellite retrievals into three mesoscale cellular convective (MCC) cloud morphology patterns. At constant amount, patterns differ in brightness associated with the amount of optically thin features. Environmentally driven transitions from closed MCC other patterns, typically accompanied by more features, are as a framework quantify contribution optical depth component shortwave feedback. marine heat wave an...
A comprehensive comparison of characteristics the planetary albedo (α) in data from two satellite measurement campaigns (ERBE and CERES) output 20 GCMs, simulating 20th-century climate, is performed. Discrepancies between different sets models exist; thus, it clear that conclusions about absolute magnitude accuracy should be drawn with caution. Yet, given present calibrations, a bias found estimates α, modelled global albedos being systematically higher than observed. The difference...
Abstract Planetary albedo—the reflectivity for solar radiation—is of singular importance in determining the amount energy taken by Earth–atmosphere system. Modeling albedo, and specifically cloud correctly is crucial realistic climate simulations. A method presented herein which regional albedo can be quantified from relation between total fraction, observations found to approximately linear on a monthly mean scale. This analysis based primarily combination fraction data Moderate Resolution...
Abstract. Aerosol–cloud interactions are a major source of uncertainty in inferring the climate sensitivity from observational record temperature. The adjustment clouds to aerosol is poorly constrained aspect these aerosol–cloud interactions. Here, we examine response midlatitude cyclone cloud properties change droplet number concentration (CDNC). Idealized experiments high-resolution, convection-permitting global aquaplanet simulations with constant CDNC compared 13 years remote-sensing...
Representing large-scale co-variability between variables related to aerosols, clouds and radiation is one of many aspects agreement with observations desirable for a climate model. In this study such relations are investigated in terms temporal correlations on monthly mean scale, identify points disagreement observations. Ten regions different meteorological characteristics aerosol signatures studied correlation matrices the selected offer an overview model ability represent present day...
Abstract. Biomass burning plumes are frequently transported over the southeast Atlantic (SEA) stratocumulus deck during southern African fire season (June–October). The bring large amounts of absorbing aerosols and enhanced moisture, which can trigger a rich set aerosol–cloud–radiation interactions with climatic consequences that still poorly understood. We use large-eddy simulation (LES) to explore disentangle individual impacts moisture on underlying clouds, marine boundary layer (MBL)...
Abstract This study focuses on the radiative properties of five subtropical marine stratocumulus cloud regions, monthly mean scale. Through examination relation between total albedo and fraction, its variability to other parameters, some factors controlling reflectivity, or albedo, clouds in these regions are investigated. It is found that main part at a given fraction can be related temporal rather than spatial variability, indicating homogeneity studied regions. seen most clearly satellite...
Abstract. The global aerosol extinction from the CALIOP space lidar was used to compute optical depth (AOD) over a 9-year period (2007–2015) and partitioned between boundary layer (BL) free troposphere (FT) using BL heights obtained ERA-Interim archive. results show that vertical distribution of AOD does not follow diurnal cycle but remains similar day night highlighting presence residual during night. FT contribute 69 31 %, respectively, tropospheric daytime in line with observations Aire...
Abstract The hemispheric symmetry of albedo and its contributing factors in satellite observations global climate models is evaluated. analysis performed on the annual mean time scale, which a bimodality joint distribution cloud fraction evident, resulting from tropical subtropical clouds midlatitude clouds, respectively. Hemispheric not found individual ocean-only latitude bands; comparing Northern Southern Hemisphere (NH SH), regional higher NH tropics lower subtropics midlatitudes than SH...
Abstract. Uncertainty in cloud feedbacks climate models is a major limitation projections of future climate. Therefore, evaluation and improvement simulation are essential to ensure the accuracy models. We analyse biases change with respect global mean near-surface temperature (GMST) relative satellite observations relate them equilibrium sensitivity, transient response feedback. For this purpose, we develop supervised deep convolutional artificial neural network for determination types from...
In a rapidly warming world, disasters are escalating in frequency and intensity. Climate-related hazards pose serious threats to affected populations, with low- middle-income countries being at greatest risk experiencing most disaster-related deaths. While the devastating impacts of these well documented, how mitigate such is less well-understood. This paper aims address this limitation aid disaster impact research by examining effects on fatalities across various types climate-related...
Abstract We study the relation between monthly mean albedo and cloud fraction over ocean, 60°S–60°N. Satellite observations indicate that these clouds all fall on same near‐exponential curve, with a monotonic distribution ranges of fractions albedo. Using observational data as reference, we examine degree to which 26 climate models capture this feature near‐global marine population. Models show general increase in increasing fraction, but none them display is well defined characterizing...