TY - JOUR
T1 - Direct and semi-direct radiative forcing of biomass-burning aerosols over the southeast Atlantic (SEA) and its sensitivity to absorbing properties
T2 - a regional climate modeling study
AU - Mallet, Marc
AU - Solmon, Fabien
AU - Nabat, Pierre
AU - Elguindi, Nellie
AU - Waquet, Fabien
AU - Bouniol, Dominique
AU - Mark Sayer, Andrew
AU - Meyer, Kerry
AU - Roehrig, Romain
AU - Michou, Martine
AU - Zuidema, Paquita
AU - Flamant, Cyrille
AU - Redemann, Jens
AU - Formenti, Paola
N1 - Funding Information:
Financial support. This research has been supported by the French
Funding Information:
Acknowledgements. This work was supported by the French National Research Agency under grant agreement no. ANR-15-CE01-0014-01; the French national program LEFE/INSU; the Programme national de Télédetection Spatiale (PNTS, http://www.insu.cnrs. fr/pnts, last access: April 2020), grant no. PNTS-2016-14; the French National Agency for Space Studies (CNES, AEROCLIM and EECLAT projects); and the South African National Research Foundation (NRF) under grant UID 105958. The research leading to these results has received funding from the European Union’s 7th Framework Programme (FP7/2014-2018) under EUFAR2 contract no. 312609. For the RegCM simulations, granted access to the HPC resources of CALMIP supercomputing center under the allocation 2019-p19062. We acknowledge all the principal investigators of the AERONET and PIRATA stations. We would like also to thank the NASA Langley Research Center Atmospheric Science Data Center, the National Center for Atmospheric Research and the Climate Research Unit for providing the data sets used to evaluate our climate simulations.
Funding Information:
This research has been supported by the French National Research Agency (grant no. ANR-15-CE01-0014-01), the French national program LEFE/INSU, the Programme national de Teledetection Spatiale (grant no. PNTS-2016-14), the French National Agency for Space Studies (CNES, AEROCLIM and EECLAT projects), and the South African National Research Foundation (NRF) (grant no. UID 105958). The research leading to these results has received funding from the European Union's 7th Framework Programme (grant no. FP7/2014-2018) under EUFAR2 (grant no. 312609). For the RegCM simulations, access was granted to the HPC resources of CALMIP supercomputing center under the allocation 2019- p19062.
Publisher Copyright:
© Author(s) 2020.
PY - 2020/11/10
Y1 - 2020/11/10
N2 - Simulations are performed for the period 2000- 2015 by two different regional climate models, ALADIN and RegCM, to quantify the direct and semi-direct radiative effects of biomass-burning aerosols (BBAs) in the southeast Atlantic (SEA) region. Different simulations have been performed using strongly absorbing BBAs in accordance with recent in situ observations over the SEA. For the July-August-September (JAS) season, the single scattering albedo (SSA) and total aerosol optical depth (AOD) simulated by the ALADIN and RegCM models are consistent with the MACv2 climatology and MERRA-2 and CAMSRA reanalyses near the biomass-burning emission sources. However, the above-cloud AOD is slightly underestimated compared to satellite (MODIS and POLDER) data during the transport over the SEA. The direct radiative effect exerted at the continental and oceanic surfaces by BBAs is significant in both models and the radiative effects at the top of the atmosphere indicate a remarkable regional contrast over SEA (in all-sky conditions), with a cooling (warming) north (south) of 10 °S, which is in agreement with the recent MACv2 climatology. In addition, the two models indicate that BBAs are responsible for an important shortwave radiative heating of ∼ 0:5-1K per day over SEA during JAS with maxima between 2 and 4 km a.m.s.l. (above mean sea level). At these altitudes, BBAs increase air temperature by ∼ 0:2-0.5 K, with the highest values being co-located with low stratocumulus clouds. Vertical changes in air temperature limit the subsidence of air mass over SEA, creating a cyclonic anomaly. The opposite effect is simulated over the continent due to the increase in lower troposphere stability. The BBA semidirect effect on the lower troposphere circulation is found to be consistent between the two models. Changes in the cloud fraction are moderate in response to the presence of smoke, and the models differ over the Gulf of Guinea. Finally, the results indicate an important sensitivity of the direct and semidirect effects to the absorbing properties of BBAs. Over the stratocumulus (Sc) region, DRE varies from C0:94Wm-2 (scattering BBAs) to C3:93Wm-2 (most absorbing BBAs).
AB - Simulations are performed for the period 2000- 2015 by two different regional climate models, ALADIN and RegCM, to quantify the direct and semi-direct radiative effects of biomass-burning aerosols (BBAs) in the southeast Atlantic (SEA) region. Different simulations have been performed using strongly absorbing BBAs in accordance with recent in situ observations over the SEA. For the July-August-September (JAS) season, the single scattering albedo (SSA) and total aerosol optical depth (AOD) simulated by the ALADIN and RegCM models are consistent with the MACv2 climatology and MERRA-2 and CAMSRA reanalyses near the biomass-burning emission sources. However, the above-cloud AOD is slightly underestimated compared to satellite (MODIS and POLDER) data during the transport over the SEA. The direct radiative effect exerted at the continental and oceanic surfaces by BBAs is significant in both models and the radiative effects at the top of the atmosphere indicate a remarkable regional contrast over SEA (in all-sky conditions), with a cooling (warming) north (south) of 10 °S, which is in agreement with the recent MACv2 climatology. In addition, the two models indicate that BBAs are responsible for an important shortwave radiative heating of ∼ 0:5-1K per day over SEA during JAS with maxima between 2 and 4 km a.m.s.l. (above mean sea level). At these altitudes, BBAs increase air temperature by ∼ 0:2-0.5 K, with the highest values being co-located with low stratocumulus clouds. Vertical changes in air temperature limit the subsidence of air mass over SEA, creating a cyclonic anomaly. The opposite effect is simulated over the continent due to the increase in lower troposphere stability. The BBA semidirect effect on the lower troposphere circulation is found to be consistent between the two models. Changes in the cloud fraction are moderate in response to the presence of smoke, and the models differ over the Gulf of Guinea. Finally, the results indicate an important sensitivity of the direct and semidirect effects to the absorbing properties of BBAs. Over the stratocumulus (Sc) region, DRE varies from C0:94Wm-2 (scattering BBAs) to C3:93Wm-2 (most absorbing BBAs).
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U2 - 10.5194/acp-20-13191-2020
DO - 10.5194/acp-20-13191-2020
M3 - Article
AN - SCOPUS:85096068968
VL - 20
SP - 13191
EP - 13216
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
SN - 1680-7316
IS - 21
ER -