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Assessment of the aerosol distribution over Indian subcontinent in CMIP5 models

Sanap, SD and Ayantika, DC and Pandithurai, G and Niranjan, K (2014) Assessment of the aerosol distribution over Indian subcontinent in CMIP5 models. Atmospheric Environment, 87. pp. 123-137.

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Abstract

This paper examines the aerosol distribution over Indian subcontinent as represented in 21 models from Coupled Model Inter-comparison Project Phase 5 (CMIP5) simulations, wherein model simulated aerosol optical depth (AOD) is compared with Moderate Resolution Imaging Spectro-radiometer (MODIS) satellite observations. The objective of the study is to provide an assessment of the capability of various global models, participating in CMIP5 project, in capturing the realistic spatial and temporal distribution of aerosol species over the Indian subcontinent. Results from our analysis show that majority of the CMIP5 models (excepting HADGEM2-ES, HADGEM2-CC) seriously underestimates the spatio-temporal variability of aerosol species over the Indian subcontinent, in particular over Indo-Gangetic Plains (IGP). Since IGP region is dominated by anthropogenic activities, high population density, and wind driven transport of dust and other aerosol species, MODIS observations reveal high AOD values over this region. Though the representation of black carbon (BC) loading in many models is fairly good, the dust loading is observed to be significantly low in majority of the models. The presence of pronounced dust activity over northern India and dust being one of the major constituent of aerosol species, the biases in dust loading has a great impact on the AOD of that region. We found that considerable biases in simulating the 850hPa wind field (which plays important role in transport of dust from adjacent deserts) would be the possible reason for poor representation of dust AOD and in turn total AOD over Indian region in CMIP5 models. In addition, aerosol radiative forcing (ARF) underestimated/overestimated in most of the models. However, spatial distribution of ARF in multi-model ensemble mean is comparable reasonably well with observations with bias in magnitudes. This analysis emphasizes the fundamental need to improve the representation of aerosol species in current state of the art climate models. As reported in Intergovernmental Panel on Climate Change (IPCC) fourth assessment report (AR4), the level of scientific understanding (LOSU) of climatic impact of aerosols is medium-low. For better understanding of short and long term implications of changing concentrations of aerosol species on climate, it is imperative to have a realistic representation of aerosol distribution over regions with high aerosol loading.

Item Type: Article
Additional Information: Copyright of this article belongs to Elsevier.
Uncontrolled Keywords: Aerosol optical depths; Aerosol radiative forcing; Anthropogenic activity; High population density; Intergovernmental panel on climate changes; Model assessment; Spatial and temporal distribution; Spatiotemporal variability, Arid regions; Atmospheric aerosols; Atmospheric radiation; Climate change; Climate models; Computer simulation; Dust; Population distribution; Population statistics; Radiometers; Satellite imagery, Loading, black carbon, aerosol property; black carbon; climate modeling; concentration (composition); dust; human activity; Intergovernmental Panel on Climate Change; MODIS; optical depth; satellite imagery; spatial distribution, aerosol; article; biomass distribution; dust; global climate; Indian; intermethod comparison; observational method; optical depth; population density; priority journal; radiative forcing; satellite imagery; simulation; spatiotemporal analysis, Gangetic Plain; India
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 05 Dec 2014 10:50
Last Modified: 05 Dec 2014 10:50
URI: http://moeseprints.incois.gov.in/id/eprint/899

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