Towards an improved representation of carbonaceous aerosols over the Indian monsoon region in a regional climate model: RegCM
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Published:2023-01-02
Issue:1
Volume:16
Page:1-15
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ISSN:1991-9603
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Container-title:Geoscientific Model Development
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language:en
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Short-container-title:Geosci. Model Dev.
Author:
Ghosh Sudipta, Dey SagnikORCID, Das Sushant, Riemer NicoleORCID, Giuliani Graziano, Ganguly DilipORCID, Venkataraman Chandra, Giorgi Filippo, Tripathi Sachchida Nand, Ramachandran Srikanthan, Rajesh Thazhathakal Ayyappen, Gadhavi HarishORCID, Srivastava Atul Kumar
Abstract
Abstract. Mitigation of carbonaceous aerosol emissions is expected to
provide climate and health co-benefits. The accurate representation of
carbonaceous aerosols in climate models is critical for reducing
uncertainties in their climate feedback. In this regard, emission fluxes and
aerosol life cycle processes are the two primary sources of uncertainties.
Here, we demonstrate that the incorporation of a dynamic ageing scheme and emission
estimates that are updated for the local sources improves the representation
of carbonaceous aerosols over the Indian monsoon region in a regional
climate model, RegCM, compared with its default configuration. The respective mean black carbon (BC) and organic carbon
(OC) surface concentrations in 2010 are estimated to be 4.25 and
10.35 µg m−3 over the Indo-Gangetic Plain (IGP) in the augmented
model. The BC column burden over the polluted IGP is found to be
2.47 mg m−2, 69.95 % higher than in the default model configuration and much
closer to available observations. The anthropogenic aerosol optical depth (AOD) increases by more
than 19 % over the IGP due to the model enhancement, also leading to a
better agreement with observed AOD. The respective top-of-the-atmosphere, surface, and
atmospheric anthropogenic aerosol short-wave radiative forcing are estimated
at −0.3, −9.3, and 9.0 W m−2 over the IGP and −0.89,
−5.33, and 4.44 W m−2 over Peninsular India (PI). Our
results suggest that the combined effect of two modifications leads to
maximum improvements in the model performance in regions where emissions play a
dominant role.
Funder
Ministry of Environment, Forest and Climate Change
Publisher
Copernicus GmbH
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