DOCTORAL CANDIDATE
Uzoma Nworgu

SUPERVISORS
Vincent Favier, Université Grenoble Alpes (UGA)
Tessa Vance, University of Tasmania (UTAS)

Climatology, Water Isotopes, Ice Cores

The Indian Ocean spans tropical to polar latitudes and is one of the most poorly understood regions in the world in terms of atmospheric circulation. Meteorological and climate information from large swathes of the region are only covered remotely by reanalysis products, which have relatively poor performance prior to the satellite era in 1979.

What is known is that cyclogenesis in the Southern Hemisphere mid-latitudes (~30-60S) is particularly intense in the Indian Ocean sector. However, the way Indian Ocean cyclogenesis interacts with downstream blocking high pressure systems is not as well understood. Many recent studies have described the influence of atmospheric rivers on extreme precipitation in Antarctica, however, the definition and/or classification of mid to high latitude ARs in the SH is too narrowly defined to capture all the synoptic scale extreme events that result from interaction between LP and HP systems in the southern Indian Ocean. It is likely many meteorological extremes (for example, extremes of surface temperature or precipitation) occur across East Antarctica that are currently poorly studied as they fall outside of the definition of an atmospheric river.

This project seeks to specifically explore whether this region of intense cyclogenesis provides a direct synoptic link between the tropical and polar regions of the Indian Ocean and specifically whether this link has changed over time by examining climate signals preserved in ice core records from the Indian Ocean sector of East Antarctica. Are there climate signals preserved in already collected ice core records that indicate past variability in any tropical/extratropical linkages in the Indian Ocean? Do these records preserve not only variability, but can we derive estimates of past changes in extreme events such as tropical to polar moisture transport, more intense or more frequent mid-latitude cyclogenesis, or past changes in the connection or lack of connection between the tropical and polar Indian Ocean. The findings from this project will be critical to understanding past variability in the Indian Ocean.