Ihanshu Rane
Contact
Email: Ihanshu.Rane@vuw.ac.nz
Office: CO531
Qualifications
BE University of Mumbai (2016); MTech Savitribai Phule Pune University (2018)
PhD Candidate in Geophysics
PhD thesis
Title
Predicting coastal polynyas in Antarctica from regional topography and large-scale atmospheric circulations
Supervisors
Project objectives and description
Coastal polynyas are areas of open water enclosed by winter sea-ice in Antarctica. Polynyas have significant impact on atmospheric, ice and oceanic processes on different spatial and temporal scales. Very cold, local high-speed winds drive the sea-ice away from the coast and at the same time intensify the generation of new sea-ice. A very dense water mass forms due to brine rejection. This eventually drives the global thermohaline circulation and ventilates the world’s deep ocean benthic eco-systems.
For studying future climate, it is important to represent formation and intensity of coastal polynyas in global Earth System Models. Simulating polynya-associated processes requires computationally expensive high-resolution models. Most smaller polynyas with intense sea-ice production are thus not represented in current global models with coarse resolutions. This leads to large biases in salt production and subsequently suppresses the formation of dense water over the Antarctic continental shelf.
The overall objective of this project is to predict coastal polynyas with Machine Learning Models using regional topography and large-scale atmospheric circulation only, thus avoiding the need to resolve fine to small scale atmospheric, oceanic, and sea-ice processes in global climate models. The project addresses two research questions. First, how does the shape of local coastal topographical features such as peninsulas, glacier tongues, bays and icebergs promote or inhibit the growth of a coastal polynya. Second, how large-scale synoptic processes trigger and enhance local high-speed winds under the influence of regional orography.