Monsoon variability in CMIP5 models
Student name: Ms Koduru Sai Maanasa
Guide: Dr Anu Rani Sharma
Year of completion: 2015
Host Organisation: Indian Institute of Tropical Meteorology (IITM), Pune
Supervisor (Host Organisation): Dr Suryachandra A. Rao
Abstract: Indian economy largely being an Agro-based and its agriculture is 80% dependent on the summer monsoon rainfall, and maximum amount of water needs of the country are primarily met by Summer Monsoon Rainfall. Being so dependent on Summer Monsoon Rainfall it becomes increasingly important to study the possible impacts of global warming on variability of the Summer Monsoon. Future projections of the monsoon variability in the CMIP5 project show a wide range of trends across various models used in it. In the recent studies, very few out of the 32 models (which were a part of CMIP5) were able to simulate the Boreal Summer intraseasonal oscillations reasonably well. Out of those few models, five models, viz., GFDL-CM3, IPSL-CM5A-LR, MIROC5, MPI-ESM-LR, CMCC-CM are found to be simulating BSISO variations in a relatively much better way.These 5 models are used in the present study to observe the possible impacts of changing climates on the Indian Summer Monsoon. All the Climate Models used in the fifth phase of the inter comparison project showed a consistent increase in the mean monsoon rainfall during the JJAS period under both RCP 4.5 & 8.5 Scenarios compared to the historic period (1985-2006). Almost all the models project a strong increase in the mean rainfall under the strongest warming RCP8.5 Scenario. High Inter annual and decadal variability of monsoon is also evident under the unabated warming scenarios like RCP8.5. Warming trend in the Western Indian Ocean SST continues to show under both the RCP Scenarios. A strong warming trend is more evident and consistent under Rcp8.5 Scenario, which would cause a more Positive IOD like situations which can counter balance the negative impacts on Indian Monsoon during EL-Nino like conditions.
