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Doctorat
Inde
2016
A Study of Climatic Processes Affecting Cloud-Rainfall-Aerosol Dynamics in Indian Coastal and Arid Region
Titre : A Study of Climatic Processes Affecting Cloud-Rainfall-Aerosol Dynamics in Indian Coastal and Arid Region
Auteur : Narayanan, Priya
Etablissement de soutenance : TERI University
Grade : Doctor of Philosophy (PhD) 2016
Résumé
Understanding the relation between cloud rainfall and aerosols is important especially in
India, since the Indian economy is determined by and dependent upon climate. This study
emphasises the strong role of the global climate indices and aerosols on rainfall at different
space-time scales. The study establishes the relation between climate indices and cloud
occurrence at different altitudinal levels. A robust selection of the spatial extent based on
earlier research is done and the relation between climate indices and cloud occurrences is
described here. Ni݊o 3.4 emerged as the most dominant index influencing cloud occurrences
over the Indian subcontinent.
The study also focuses on the patterns of trend in rainfall over the arid North Western and
the coastal South Eastern Indian regions. Non-parametric statistical tests show some
significant positive and negative trends in rainfall at 10% level of significance. Spatial
heterogeneity in rainfall pattern along temporal scales is also observed. The Pettit Mann
Whitney test (PMW) shows a definitive change in rainfall pattern for the arid North Western
region and the coastal South Eastern region post the 1970s conforming to the established
global climate shift theory. Further, the Principle Component Analysis (PCA) used in this
study explores the most dominating indices affecting rainfall over the North Western region.
This study also assesses the spatial and temporal variability of Aerosol Optical Depth (AOD)
for the arid North Western and the coastal South Eastern Indian region based on the
observations from Moderate Resolution Imaging Spectroradiometer (MODIS). The Aerosol
Indirect Effect (AIE) computed for the South Eastern Indian region shows a strong warming
scenario. Further, a strong relation between rainfall and AOD is also observed and is
interpreted in detail in this study.
In this study the relation between the cloud, rainfall, and aerosol interactions for the globalto-local
scales and vice-versa have been explained in detail.
Page publiée le 15 novembre 2017