Estimation of aerosol variability over the Indian subcontinent: a comparative study as simulated by CMIP5 models and satellite data
Student name: Mr Nilesh Maiti
Guide: Dr Anu Rani Sharma
Year of completion: 2016
Host Organisation: Center for Atmospheric Sciences, IIT Delhi
Supervisor (Host Organisation): Dr Sagnik Dey
Abstract: According to IPCC, aerosols contribute to the largest uncertainties in estimating and interpret-ing the Earth’s radiation budget. It states the level of scientific understanding (LOSU) of aero-sols on the climate is medium-low. It is important to quantify the climate forcing due to the aero-sols and its feedbacks on the regional climate in particular, in order to examine their impact. There is a need for a realistic spatio-temporal representation of aerosols over the region experi-encing high aerosol loadings. The present study is an attempt to quantify the loadings over the Indian region with an emphasis on the oceans of Arabian Sea and Bay of Bengal, which are con-sidered as regional hotspots for aerosols. Their distributions over the region as simulated by the various CMIP5models have been examined and compared with the satellite derived estimations. The study has been carried out in order to analyze the realism in these various climate models and their fidelity over the Indian region. A long term spatio-temporal analysis reveals that none of the models are able to estimate the aerosol variability over the region as compared to the sat-ellite estimation. There is a high degree of biasness in the AOD values for each season. In addi-tion, the study also focuses on the various RCP projections for future climate change scenario being impacted by these species. The results reveal an inconsistent trend of AOD over the coming years till 2100. However, it is expected that the loadings tend to decrease. These models cannot be considered suitable for estimating the aerosol variability for the future scenarios henceforth, even though their statistical associations with satellite estimates are good. The study reveals a need for an improvement in these models for AOD representation over the Indian subcontinent.
Keywords: Aerosols, CMIP5 models, satellite observations, spatio-temporal analysis, RCP sce-narios
