Late Quaternary Indian Monsoon Variability Inferences from Marine and Continental Records

Abstract

Indian monsoon is considered as one of the most powerful circulation system manifested by the seasonal wind reversal driven by the north-south movement of the Inter-Tropical Convergence Zone across the equator causing enormous change in the hydrological system. This change of hydrological system affects the economy, culture, society, land use, vegetation, etc., across the Indian subcontinent. To understand the variability of the monsoon rainfall and its associated causative factors, continuous monitoring of meteorological parameters is essential for climate modeling and future prediction. However, long term study from the past is not possible as the instrumental data is available only for about a century. Hence, long term records of monsoonal variability are studied from several natural proxies. A chronological parameter is also essential in assigning the temporal range to the proxy based climatic reconstruction in geological time scale. The proxy based studies together with geochronology make the scientific explanations stronger in reconstructing the paleoclimate. Paleoclimatic studies using various proxies such as marine sediments, lacustrine sediments, tree rings, stalagmites, etc., have been carried out from Indian region. Studies on monsoon reconstruction from the past indicate that several ancient civilizations suffered due to the adverse changes in Indian monsoon causing severe drought and/or floods. The literature review of Indian monsoon reconstruction from various proxies of marine and continental domains give an insight in to the Indian monsoon mechanism and its dynamics, which is very complex and has varied truly out of the box of its convenient mode of variability at different time intervals. Hence, it is very important to have its reconstruction at high resolution so that the minute changes and the variabilities on the cyclic pattern of the monsoon system can be understood. Thus, to understand the Indian monsoon variability, and#948;18O and and#948;13C isotopic studies of two planktic foraminifera: Globigerina bu