Evolution of Indian Summer Monsoon to its current strength (eISM)

Lead Research Organisation: Open University
Department Name: Faculty of Sci, Tech, Eng & Maths (STEM)


The Indian Summer Monsoon (ISM) is a result of coupled solid Earth and atmospheric processes. The ISM is due to anomalous heating of the air mass over central Asia resulting in the formation of a low-pressure system that draws moist air from the surrounding oceans resulting in intense precipitation across Indochina and south Asia, impacting billions of people. The processes responsible for intensity of this low-pressure system over the continent is related to the regional tectonics since the initial collision of India with Asia around 50 Ma (million year ago) during the Cenozoic. How intensity of monsoon climate, especially rainfall, affects continental erosion and consequently exhumation and uplift of Himalaya and Tibet is largely unknown mainly due to poor constrains on Cenozoic evolution of monsoon. Previous attempts to reach consensus on past ISM intensity is hindered by lack of continuous sedimentary sequences and robust proxies. This project, eISM, will address these shortcomings by (a) utilising newly drilled sediment sequences from three sites in the Bay of Bengal and Andaman Sea, one of the core regions of ISM precipitation, through International Ocean Discovery Programme (IODP) expedition 353 and (b) applying tested proxies for salinity (oxygen isotope of seawater and Ba/Ca ratio from planktonic foraminifera) and erosional strength (from bulk elemental ratio) to reconstruct evolution of ISM precipitation. Monsoon records generated in eISM will help correlate with the increasingly well-constrained onshore tectonic history, in order to understand and quantify the impact of climate-modulated processes in controlling tectonic evolution on Earth.

Planned Impact

The scientific outcomes of eISM will improve understanding of one of the largest and most influential climatic systems in the world with direct relevance to billions of people in south Asia. Deficient rainfall leads to drought and famine, while excessive rainfall leads to flooding and similarly adverse impacts to society and economies. The Indian Summer Monsoon (ISM) has significant economic, social and environmental repercussions for the agriculture, flora and fauna of South Asia as it provides up to 80% of annual rainfall in India. Improved knowledge of controls on this climatic system will be essential for policy makers looking to manage resources for future drinking-water security and their economic wellbeing, the majority of which are dependent on the ISM for agricultural success. The rapidly growing global community will also benefit from understanding how future changes in ISM intensification could affect their livelihoods, food and water security.

Scientist and researcher working on eISM will benefit immensely with new collaborations and interactions with shipboard and shore based IODP scientists during sampling, data generation and presentation of results. In addition, members of the scientific community will benefit from the collaboration between palaeoceanographers and solid earth geologists, who can use each other's knowledge and expertise to understand how/if the monsoon evolution is linked to tectonic evolution of Asia and how the monsoon could in turn, be controlling the current tectonic uplift through increased continental weathering. The work will directly benefit scientists trying to quantify sediment discharge from erosion of uplifted Himalaya and its impact on CO2 drawdown and climate.
Description We have obtained preliminary results that indicate a potential contribution of climate and tectonics in controlling Monsoon hydroclimate. The data is currently being written for a data report to be submitted at IODP results volume. Additional data is also being evaluated for a journal article.
Exploitation Route We are going to use the initial findings of the project to run climate models to ascertain factors responsible for changes in Indian Summer Monsoon. We are in the process of developing models to test the role of climate and tectonics for the Indian summer monsoon evolution.
Sectors Education,Environment

Description Our findings informed 'A' level science students about controlling factors on monsoon hydroclimate during summer placements. Three Nuffield funded placement students were given opportunities to learn about monsoon and climate and work on recently collected samples. I have also been selected to talk about my ongoing research in a soapbox science event on 29th July 2017 in Milton Keynes where I will be talking about my research involving shells in working out past ocean environment. Additionally, I have presented scientific findings at the second post-cruise Science meeting of the International Ocean Discovery Programme between 6 to 8th November 2017 in India.
First Year Of Impact 2015
Sector Education,Environment,Other
Impact Types Societal

Description Reconstructing past Indian Summer Monsoon variability since 6 Ma 
Organisation University of Colorado Boulder
Country United States 
Sector Academic/University 
PI Contribution Through the funded project (eISM), my team generated data that will contribute to this collaborative project. Our collected data of oxygen isotope of planktic foraminifera, bulk sediment elemental composition, bulk total organic carbon and total organic nitrogen and bulk organic carbon and nitrogen isotopic will contribute towards publications in near future.
Collaborator Contribution Collaborator Ms Jody Wycech has generated trace element data from site U1447. When coupled with my oxygen isotope data it would provide a reconstruction of past runoff variability in the Andaman Sea. Further coupling of these data with the bulk geochemical data, will provide a robust constraint on past Monsoon runoff variability.
Impact None yet as the samples for oxygen isotope is currently running.
Start Year 2018