Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Spatio Temporal Analysis of the Effect of Climate Change on Drought Variability and Future Drought Projections in India

Auteur : Ulhas, Barde Vasundhara

Université de soutenance : Indian Institute of Technology Bhubaneswar

Grade : Doctor of Philosophy (PhD) 2022

Résumé
Understanding the drought, severity, intensity and spatial variation is quite important in the recent years in the context of climate change. In the recent decades, India is frequently experiencing drought-like conditions. The drought in India is linked with the inter-annual variability of summer monsoon rainfall. The Indian Summer Monsoon (ISM) plays an important role in the different sectors such as agriculture, hydrology, water resources availability and management, hydro-power of the country. The ISM is a complex phenomenon with nonlinear interactions between large-scale circulations and small-scale physical processes. The rainfall associated with ISM exhibits temporal and spatial variability. Till date, the mechanism of ISM is not fully understood. The spatiotemporal variability of ISM rainfall has been studied extensively. However, the spatiotemporal variability of drought-prone areas of India in the context of climate change gets less attention. Therefore, in the reported study the spatiotemporal variability of ISMR and changes in major drought- prone areas in the context of climate change is discussed. The Monsoon Sparse Zone (MSZ), is a zone with less seasonal rainfall compared to the long-term average climatology. Identifying the MSZ is crucial to understanding the spread and propagation of drought-prone areas. The present study investigates the nature of the MSZ shift in India during the past century and probable meteorological factors responsible for those transitions. For this purpose, the high-resolution daily rainfall analysis (0.25˚×0.25˚) from India Meteorological Department (IMD), sea surface temperature from National Oceanic and Atmospheric Administration (NOAA_ERSST_V4) (2.5˚×2.5˚), Standardized precipitation evapotranspiration index (SPEI) from Climate Research Unit (0.5˚×0.5˚), and other meteorological parameters from NCEP-NCAR reanalysis are used. In the process of identifying the future location of MSZ, Coordinated Regional Climate Downscaling Experiment-South Asia (CORDEX-SA) Regional climate models simulations are used. Two drought indices are used to study the MSZ and its shifts over India. The MSZ locals follows the counter-clockwise transition from west to north-central India through the peninsular region from one to another epoch. Detailed analysis suggests that Large-scale regional processes that may impact the shift of MSZ are to be analyzed. The statistical analysis of the CORDEX-SA data indicates that the MSZ will continue the counter-clockwise march over India. The MSZ location is likely to be shifted over to northwest India through central India in the future. This shift is of concern as it indicates that the region that is seeing continued growth in the population and has increased agricultural intensification could lead to cascading impacts.

Présentation et version intégrale (Shodhganga)