Sri Durgesh Nandini

Sri Durgesh Nandini

Institute and email: MARUM, University of Bremen, GERMANY

Statement of interest: My early childhood curiosity for underwater fascinations such as coral reefs has lead to a passionate hobby and research career choice in trying to understand the past, present and future climate change impacts on ocean science.

Background

My academia consists of a bachelors in Marine Science and Masters qualifications and training's from USP, CSIRO, University of Hawaii and Woods hole Oceanographic Institute, in the field of climate change and modeling climate science.

My goal is to help Fiji mitigate the effects of climate change on rural and coastal communities such as degradation of coral reefs and associated loss in marine/land biodiversity. Hence, I was motivated to join the PRIDE programme where I would be bestowed with the much-needed skills and a collaborative scientific network as well as long lasting friendships with my PRIDE colleagues and friends to ensure this. I am convinced that with the best state of art climate models, libraries, scholarly articles, world renounced climate scientists found in the  PRIDE Programme, I will  achieve excellent results/skills for my intended research to apply back home in Fiji.

 

Project description

Hydroclimate Dynamics in the Late Quaternary Pontocaspian Region Simulated by a Global Climate Model

The project is part of the EU-funded MSCA-ITN “Pride” (Pontocaspian biodiversity Rise and Demise). In this project I will perform numerical experiments using a state-of-the-art fully coupled climate model, the Community Earth System Model (CESM1.2) to study past climate change in the Eurasian region with a special eye towards the Pontocaspian area. Today, this region consists of a vast steppe land stretching from the northern shores of the Black Sea, as far east as the Caspian Sea. It contains an important system of basins with unique environmental features and paleogeographical history. Furthermore, it is strongly affected by climate change. In particular, river inflow and the local balance between evaporation and precipitation are main drivers for variations in sea/lake levels. Despite abundant research findings, major questions regarding variations in past climate  history as well as the hydrologic cycle are still being debated and  there is no general consensus regarding the interrelation of past climatic events as well as the response of this region to future global climate change. Therefore, I aim to understand the past and current drivers of hydroclimate dynamics and large-scale atmospheric variability  which may have regional impacts on the lake basins in this area. Beside climate variability at the orbital timescale, millennial-scale variations in the Black and Caspian Seas associated with Heinrich and Dansgaard-Oeschger (D-O) events shall be examined.  Dansgaard-Oeschger events are characterized by rapid warmings in the North Atlantic realm followed by cooling periods lasting a few hundred of years and occurred 25 times during the last glacial. Heinrich events occurred in the cold spells preceding the D-O warm events. These events may have been triggered by influx of fresh water, solar amplifications or changes in the size of the ice sheets which determine the North Atlantic ocean circulation by altering the northern hemisphere westerly winds, Gulf Stream and sea-ice systems. Proxy records suggest that these millennial-scale events had a climatic impact on the Pontocaspian region.

 

One of the major aims of this project is to evaluate the temporal evolution of the lake systems and climate conditions during glacial and interglacial stages of the late Quaternary period. More specifically, I will explore the impact of changing hydroclimate on lake-surface area by analyzing the regional balance between precipitation and evaporation (P-E) in cooperation with a lake modeller from the University of Reading. To this end, I will generate a series of time slice climate model simulations through glacial-interglacial cycles over the past 1 million years with a special focus on the last 150,000 years. All computational simulations will be performed with the supercomputer platform HLRN. Freshwater hosing experiments will further be performed to asses the effects of Heinrich and Dansgaard-Oeschger events on the regional hydroclimate. The output of CESM1.2 will be used to drive a lake model of the Pontocaspian region at the University of Reading. Moreover, the impact of lake-surface areas on regional climate shall be studied at a later stage of this project. There will be two secondments at PRIDE project partners, the first secondment at Reading University (UK) for two months to integrate the climate and lake-basin models, and another secondment at Bristol University (UK) for one month for model and proxy data comparison. The major results expected include (1) new climate simulations of the Quaternary, (2) P-E data to force a Pontocaspian lake model and (3) assessment of the impact of lake-surface area on regional climate. I expect to present results at national and international conferences and to publish in peer reviewed international journals. Lastly, I intend to achieve a doctoral qualification and graduate in this field.

 

Scientific objectives:

1) Evaluate the climatic dynamics during the last glacial-interglacial cycles of the late Quaternary through paleoclimate modeling simulations/experiments (draft publication 1)

2) Contrast between the last and present interglacial regarding hydroclimate dynamics and lake evolution in the Pontocaspian region using a coupled climate model (draft publication 2)

3) Analysis of variations in mid-latitude atmospheric dynamics (e.g., the Westerlies) throughout the late Quaternary and its influence on the Pontocaspian region (draft publication 3)

 

Languages spoken

Excellent knowledge of Pacific culture and community work. Excellent Command of written and oral English and Hindi. Beginners Certificate in French and German.