  Assessments of impacts of climate change and future projections over the
Indian region, have so far relied on a single regional climate model (RCM) -
eg., the PRECIS RCM of the Hadley Centre, UK. While these assessments have
provided inputs to various reports (e.g., INCCA 2010; NATCOMM2 2012), it is
important to have an ensemble of climate projections drawn from multiple RCMs
due to large uncertainties in regional-scale climate projections. Ensembles of
multi-RCM projections driven under different perceivable socio-economic
scenarios are required to capture the probable path of growth, and provide the
behavior of future climate and impacts on various biophysical systems and
economic sectors dependent on such systems.
  The Centre for Climate Change Research, Indian Institute of Tropical
Meteorology (CCCR-IITM) has generated an ensemble of high resolution downscaled
projections of regional climate and monsoon over South Asia until 2100 for the
Intergovernmental Panel for Climate Change (IPCC)using a RCM (ICTP-RegCM4) at
50 km horizontal resolution, by driving the regional model with lateral and
lower boundary conditions from multiple global atmosphere-ocean coupled models
from the Coupled Model Intercomparison Project Phase 5 (CMIP5). The future
projections are based on three Representation Concentration Pathway (RCP)
scenarios (viz., RCP2.6, RCP4.5, RCP8.5) of the IPCC.
