Advantage of NEX-GDDP over CMIP5 and CORDEX Data: Indian Summer Monsoon

Abstract

Recently released NASA's Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) data (surface air temperature and precipitation) are evaluated using the observations from the India Meteorological Department (IMD) and compared with CMIP5 and CORDEX data to show its advantage over the Indian subcontinent for the summer monsoon season. The multi-model mean of 21 NEX-GDDP models, 28 CMIP5 models, and 10 CORDEX models are analyzed for the period of 1975–2005. In general and over most parts of the subcontinent, the NEX-GDDP is found to be quite satisfactory and surpasses the CMIP5 and CORDEX data. The NEX-GDDP data captures the spatial patterns of seasonal mean temperatures and precipitation with highest accuracy (pattern correlation of ~0.8) and least errors (root mean square error of ~ 4.25 °C and ~2.48 mm day−1); the inter-annual variations in precipitation are closer to the observations (r = 0.66 and standard deviation = 0.36 mm day−1); bias in the annual cycle reduces; simulation of extremes is more realistic with less inter-model differences. Remarkable improvements in this data suggest its potential application for future projections and climate change impact studies at the regional scale.