By: P Suneetha, P Latha, S Ramalingeswara Rao, K Nagalakshmi, D Melchi Zedek and Bhanu Kumar, O S R U

Keywords: IPCC, SRES, projections, baseline period, South India.

Abstract: Northeast monsoon (NEM) season plays an important role in producing the rainfall over south India through intense heavy rainfall events, tropical cyclones and easterly waves. This study aims to understand climate change phenomenon for the past century (20th century) over south India during northeast monsoon season in terms of rainfall and temperature projected for 21 st century using IPCC AR4 model outputs. Historical study of surface-air-temperature and rainfall were made using 22 IPCC AOGCMs. Of them GFDL_CM2.0, GFDL_CM2.1, CNRM, CGCM-T63 and MPI model projections show the signature of the rainfall and temperature reasonably good by validating with available datasets CMAP and CRU respectively. The future climate projection scenarios are based on SRES A1B scenarios over south Indian region in three time-slices viz. short (2020s), medium (2050s) and long (2080s) periods. The rainfall exhibits increasing trend in 2020s (4 mm/day) and 2080s (7mm/day) when compared with the 2050s (2mm/day). It is striking to note that the spatial distribution of NEM rainfall is shifting towards the western part of south India in 2020s and 2080s. Next, the temperature projections also represent 3.5°C rise in temperature over south India in 2080s when compared with the baseline period. Thus, the IPCC AR4 model SRES A1B scenarios representing the rise in temperature and rainfall during NEM season over south India for 21st century.

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