A5083221868- Atmospheric chemistry and aerosols
- Atmospheric aerosols and clouds
- Climate variability and models
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Meteorological Phenomena and Simulations
- Climate Change Policy and Economics
- Air Quality and Health Impacts
- Global Energy and Sustainability Research
- Climate Change and Geoengineering
- Carbon Dioxide Capture Technologies
- Vehicle emissions and performance
- Geophysics and Gravity Measurements
- Air Quality Monitoring and Forecasting
- Environmental Impact and Sustainability
- Climate Change, Adaptation, Migration
- demographic modeling and climate adaptation
- Cryospheric studies and observations
- Climate change impacts on agriculture
- Climate Change and Health Impacts
- Gas Dynamics and Kinetic Theory
- Hydrology and Drought Analysis
- Energy, Environment, and Transportation Policies
- Urban Heat Island Mitigation
- Oil, Gas, and Environmental Issues
CICERO Center for International Climate Research
2016-2025
Climate Foundation
2023
University of Oslo
2008-2018
The intensity of the heaviest extreme precipitation events is known to increase with global warming. How often such occur in a warmer world however less well established, and combined effect changes frequency on total amount rain falling as much explored, spite potentially large societal impacts. Here, we employ observations climate model simulations document strong increases frequencies occurring decadal timescales. Based find that from these intense almost doubles per degree warming,...
Abstract We investigate the climate response to increased concentrations of black carbon (BC), as part Precipitation Driver Response Model Intercomparison Project (PDRMIP). A tenfold increase in BC is simulated by nine global coupled‐climate models, producing a model median effective radiative forcing 0.82 (ranging from 0.41 2.91) W m −2 , and warming 0.67 (0.16 1.66) K globally 1.24 (0.26 4.31) Arctic. strong positive instantaneous (median 2.10 based on five models) countered negative rapid...
As the global temperature increases with changing climate, precipitation rates and patterns are affected through a wide range of physical mechanisms. The globally averaged intensity extreme also changes more rapidly than rate. While some aspects regional variation in predicted by climate models appear robust, there is still large degree inter-model differences unaccounted for. Individual drivers change initially alter energy budget atmosphere leading to distinct rapid adjustments involving...
Abstract The Arctic is experiencing rapid climate change in response to changes greenhouse gases, aerosols, and other drivers. Emission general, as well geographical shifts emissions transport pathways of short‐lived forcers, make it necessary understand the influence each driver on Arctic. In Precipitation Driver Response Model Intercomparison Project, 10 global models perturbed five different drivers separately (CO 2 , CH 4 solar constant, black carbon, SO ). We show that annual mean...
Abstract. Aerosol-induced absorption of shortwave radiation can modify the climate through local atmospheric heating, which affects lapse rates, precipitation, and cloud formation. Presently, total amount aerosol is poorly constrained, main absorbing species (black carbon (BC), organic aerosols (OA), mineral dust) are diversely quantified in global models. As part third phase Aerosol Comparisons between Observations Models (AeroCom) intercomparison initiative (AeroCom III), we here document...
Abstract In the present study, surface solar radiation data from 11 stations in northwestern Europe and European Arctic are presented context of ongoing discussion on global dimming brightening. The records compared to cloud cover, qualitative information aerosol concentrations atmospheric circulation patterns, order explain temporal variations. Through simple statistical analyses, we examine annual trends as well for individual months, compare results between stations. Comparisons also made...
Abstract. The response of clouds to sudden decreases in the flux galactic cosmic rays (GCR) – Forbush decrease events has been investigated using cloud products from space-borne MODIS instrument, which operation since 2000. By focusing on pristine Southern Hemisphere ocean regions we examine areas where believe that a ray signal should be easier detect than elsewhere. While previous studies have mainly considered cover, high spatial and spectral resolution allows for more thorough study...
Globally, latent heating associated with a change in precipitation is balanced by changes to atmospheric radiative cooling and sensible heat fluxes. Both components can be altered climate forcing mechanisms through feedbacks, but the impacts of feedbacks on fluxes have received much less attention. Here we show, using range modelling results, that are dominant contributor present global-mean since preindustrial time, because impact forcings approximately compensate. The model results show...
Abstract. Marine cloud brightening through sea spray injection has been proposed as a climate engineering method for avoiding the most severe consequences of global warming. A limitation previous modelling studies on marine is that they have either considered individual models or only investigated effects specific increase in number droplets. Here we present results from coordinated simulations with three Earth system (ESMs) participating Geoengineering Model Intercomparison Project (GeoMIP)...
Abstract. Atmospheric aerosols and greenhouse gases affect cloud properties, radiative balance and, thus, the hydrological cycle. Observations show that precipitation has decreased in Mediterranean since beginning of 20th century, many studies have investigated possible mechanisms. So far, however, effects aerosol forcing on remain largely unknown. Here we compare modeled dynamical response to individual agents a set global climate models (GCMs). Our analyses both can cause drying is more...
Abstract Global warming due to greenhouse gases and atmospheric aerosols alter precipitation rates, but the influence on extreme by relative is still not well known. Here we use simulations from Precipitation Driver Response Model Intercomparison Project that enable us compare changes in mean with those black carbon sulfate aerosols, using indicators for dry extremes as moderate very precipitation. Generally, find more a event is, pronounced its response global surface temperature change,...
Black carbon (BC) aerosols from incomplete combustion generally warm the climate, but magnitudes of their various interactions with climate are still uncertain. A key knowledge gap is role as ice nucleating particles (INPs), enabling formation in clouds. Here we assess global radiative impacts BC acting INPs, using simulations Community Earth System Model 2 model updated to include new laboratory-based nucleation parameterizations. Overall, find a moderate cooling through changes stratiform...
Abstract. Here we show results from Earth system model simulations the marine cloud brightening experiment G4cdnc of Geoengineering Model Intercomparison Project (GeoMIP). The nine contributing models prescribe a 50 % increase in droplet number concentration (CDNC) low clouds over global oceans an dubbed G4cdnc, with purpose counteracting radiative forcing due to anthropogenic greenhouse gases under RCP4.5 scenario. ensemble median effective (ERF) amounts −1.9 W m−2, substantial inter-model...
Different climate drivers influence precipitation in different ways. Here we use radiative kernels to understand the of rapid adjustment processes on models. Rapid adjustments are generally triggered by initial heating or cooling atmosphere from an external driver. For changes, due changes temperature, water vapor, and clouds most important. In this study have investigated five (CO2, CH4, solar irradiance, black carbon, sulfate aerosols). The fast responses a doubling CO2 10-fold increase...
[1] Here we investigate whether the large variations in anthropogenic aerosol concentrations over last decades have had a notable effect on precipitation Europe. Our main focus is heavily industrialized region formerly known as Black Triangle (BT), where pollution levels increased until late 1980s and then decreased substantially. Precipitation changes this area are compared to clean coastal western Europe with minor trends but potentially higher aerosol-precipitation susceptibility. We find...
Abstract We are investigating the fast and slow responses of changes in mean extreme precipitation to different climate forcing mechanisms, such as greenhouse gas solar forcing, understand whether rapid adjustments important for precipitation. To disentangle effect adjustment a given on overall change precipitation, we use linear regression method that has been previously applied Equilibrium experiments with preindustrial CO 2 concentrations reduced constant were compared four times...
Abstract. In the Hemispheric Transport of Air Pollution Phase 2 (HTAP2) exercise, a range global atmospheric general circulation and chemical transport models performed coordinated perturbation experiments with 20 % reductions in emissions anthropogenic aerosols, or aerosol precursors, number source regions. Here, we compare resulting changes load vertically resolved profiles black carbon (BC), organic aerosols (OA) sulfate (SO4) from 10 that include treatment aerosols. We use set...
Abstract We compare six methods of estimating effective radiative forcing (ERF) using a set atmosphere‐ocean general circulation models. This is the first multiforcing agent, multimodel evaluation ERF values calculated different methods. demonstrate that previously reported apparent consistency between derived from fixed sea surface temperature simulations and linear regression holds for most climate forcings, excluding black carbon (BC). When land adjustment accounted for, however, are...
Abstract. Mitigation of non-CO2 emissions plays a key role in meeting the Paris Agreement ambitions and sustainable development goals. Implementation respective policies addressing these targets mainly occur at sectoral regional levels, designing efficient mitigation strategies therefore relies on detailed knowledge about mix from individual sources their subsequent climate impact. Here we present comprehensive dataset near- long-term global temperature responses to CO2 short-lived forcers...
Abstract. The diurnal temperature range (DTR) (or difference between the maximum and minimum within a day) is one of many climate parameters that affects health, agriculture society. Understanding how DTR evolves under global warming therefore crucial. Physically different drivers change, such as greenhouse gases aerosols, have distinct influences on regional climate. Therefore, predicting future evolution requires knowledge effects individual forcers, well emissions mix, in particular...
Abstract The climate system responds to changes in the amount of atmospheric greenhouse gases or aerosols through rapid processes, triggered within hours and days, slower where full response may only be seen after centuries. In this paper, we aim elucidate mechanisms operating on time scales years better understand key quantities such as energy fluxes, temperature, precipitation a sudden increase either carbon dioxide (CO 2 ), black (BC), sulfate (SO 4 ) aerosols. results are based idealized...
Abstract. In 2020 the International Maritime Organization (IMO) implemented strict new regulations on emissions of sulphate aerosol from world's shipping fleet. This can be expected to lead a reduction in aerosol-driven cooling, unmasking portion greenhouse gas warming. The magnitude effect is uncertain, however, due large remaining uncertainties climate response aerosols. Here, we investigate this question using an 18-member ensemble fully coupled simulations evenly sampling key modes...
Abstract. CloudSat estimates that 1773 km3 of snow falls, on average, each year over the world's mountains. This amounts to 5 % global snowfall accumulations. study synthetizes mountain four continents containing mountains (Eurasia, North America, South America and Africa), comparing from a new satellite cloud-radar-based dataset those widely used reanalyses: Modern-Era Retrospective analysis for Research Applications (MERRA), MERRA-2, Japanese 55-year Reanalysis (JRA-55), European Center...
Abstract Ventilation of health hazardous aerosol pollution within the planetary boundary layer (PBL) – lowest atmosphere is dependent upon turbulent mixing, which again closely linked to height PBL. Here we show that emissions both CO 2 and absorbing aerosols such as black carbon influence number severe air episodes through impacts on turbulence PBL height. While cause increased stability reduced atmospheric heating, has opposite effect over land surface warming. In future scenarios with...