Research Projects

Studies of paleomonsoon answer questions about what the nature of monsoons was like in the past and enable projections, plans, and preparations for the future. The Intergovernmental Panel on Climate Change (IPCC), through its various reports, has anticipated a future scenario of Global Warming in which changing monsoon patterns will greatly affect countries like India, whose one-fifth of GDP comes from agriculture. Despite sophisticated models being used for projecting monsoon behaviour, the efforts have not met the expectations due to a poor understanding of the teleconnectivity of the Indian monsoon with other global climatic variability and a lack of inputs from paleoclimate studies. Though the Indian Monsoon variability has been related to factors like North Atlantic Cooling, Antarctic Climate Changes, and Solar forcings, the most important controlling factors can be understood when an ancient analogue to modern and projected warming scenarios is studied and results are made available to the Climate Models. In order to make our climate models more robust, the palaeoclimatologists have been looking for an ancient analog to a warm climate as it is today, with more warming predicted for the future. The paleoclimate data point to the Middle Piacenzian Stage of the Pliocene Epoch, in which the global warming was more than the present. In addition, studies by Fedorov et al ( 2006) and Wara et al ( 2011) revealed permanent El Niño ( El Padre) conditions in the Early Pliocene. The Mid-Pliocene was followed by icehouse conditions with the initiation of Northern Hemisphere glaciation in the Late Pliocene. The present proposal aims to understand behaviour of Indian Monsoon during (a) Early Pliocene Closing of Indonesian Seaway when Indonesian through flow nature changed from a warm south Pacific waters to cooler North Pacific waters (b) Early Pliocene permanent El Niño state ( El Padre), (c) Mid Pliocene Warmth (Mid Piacenzian- 3.3-3.0Ma), (d) Late Pliocene Northern Hemisphere Glaciation ( 2.8-.26 Ma), and (e) Mid Pleistocene Transition ( 1.2- 0.9 Ma) which involved a change from 40 kyr to 100 kyr paced glacial-interglacial cycles.We will be identifying precisely the five critical intervals based on detailed planktic foraminiferal biostratigraphy integrated with Magnetochronology. These intervals are beyond the scope of Radiocarbon dating, and only integrated stratigraphy can give a precise age. We plan to generate high-resolution time series data on the variability of the Indian Monsoon through a Deep-Sea Core in the Western Arabian Sea ( ODP Site 722). The ITF variability will be studied by high-resolution time series proxy data from the Western Pacific Warm Pool ( ODP Site 807) and the Northern Indian Ocean (ODP Site 716). The Western Arabian Sea experiences intense upwelling near the Somali margin during the Indian Summer Monsoon, and the upwelling indices of planktic foraminifera have been used to infer the monsoon wind strength. However, such studies have been based on poor sample resolution. We also wish to test two important hypotheses. One is the impact of the Early Pliocene closing of the Indonesian Seaway and changing nature of Indonesian throughflow, which led to East African aridification on the Indian Monsoon variability, and the other is the effect of a proposed permanent El Niño-like condition (5- 3 Ma on the Indian Monsoon. The anticipated impact of the proposal would help in our understanding of the impact of the long-term mean state of El Niño on the Indian Monsoon variability under a future global warming scenario. This will also be useful for predictive climate modelling, where several parameters for the projection of monsoon are taken into consideration. Our data and results on paleomonsoon reconstructions will provide different boundary conditions for climate models that must test any model’s ability to “hindcast” past climates, like the one in the Mid-Pliocene and during a permanent El Niño state.