Understanding the Indian
monsoon behavior in a changing climate using the IITM Earth System
Model: Implications for monsoon predictability
R. Krishnan
Indian Institute of Tropical Meteorology
15 May, Noon, in 2155
Abstract:
Observations indicate that the Indian landmass experienced significant
surface warming at a rate exceeding 0.6oC (100 years)-1, since
beginning of the 20th century. Precipitation datasets reveal a
decreasing trend in summer monsoon rains over the region by about 7%
since 1950s, together with significant increases in the frequency and
intensity of heavy precipitation (intensity > 100 mm day-1)
occurrences that have adversely affected the regional hydro-climate. We
conducted numerical simulation experiments using the IITM Earth System
Model (IITM ESM), which has been developed from the NCEP CFS-v2 climate
forecast system, to understand the impact of climate change on the
Indian summer monsoon. The IITM ESM is a radiatively balanced climate
modeling framework that has been developed at the Centre for Climate
Change Research (CCCR), Indian Institute of Tropical Meteorology
(IITM), Pune for studying long-term climate variability and change, as
well as the Earth System response to human-induced climate change.
The results from the present study point to the role of human-induced
climate change on the declining trend of summer monsoon precipitation
over the Indian subcontinent. In particular, the IITM-ESM simulations
suggest that the combined influence of anthropogenic aerosol forcing
and global warming has likely suppressed organized summer monsoon
convection, weakened the monsoon circulation and in turn caused
decrease of precipitation over the region. The detailed physical
mechanisms of the Indian monsoon response to Greenhouse Gas (GHG) and
anthropogenic aerosol forcing would be discussed during the
presentation. The present findings have implications for the role of
climate change on the subseasonal-to-seasonal predictability of the
Indian summer monsoon.