Research

Indonesian Throughflow Variability

The Indonesian Throughflow (ITF) is a series of ocean passageways by which tropical Pacific waters flow into the Indian Ocean. Because the ITF transports a significant magnitude of heat and freshwater between the two basins, it plays a critical role in Indo-Pacific climate variability. I am interested in understanding ITF dynamics on decadal-centennial timescales using ocean general circulation models and marine sediment archives.

Southeast Asian Rainfall Extremes

Throughout the last millennium, Southeast Asia experienced periods of extended drought and severe flooding associated with variations in monsoonal rainfall. These rainfall extremes contributed to societal changes across Asia such as the Khmer Empire’s abandonment of Angkor (15th century) and the collapse of the Ming Dynasty in China (17th Century). I am interested in understanding the various drivers of these past hydroclimate extremes. In a recent study, I utilized an ensemble of climate simulations (CEMS-LME) to quantify the internal and external contributions to multi-year extremes in Southeast Asia.

Indo-Pacific Basin Interactions

The tropical Pacific and Indian Oceans are not only connected through the Indonesian Throughflow, but also through atmospheric pathways. Indeed the large-scale zonal circulations over the Pacific and Indian Oceans (Walker Circulations) share their ascending limb over the Indo-Pacific Warm Pool (IPWP). This connectivity leads to the observed moderate coupling between the two basins on interannual timescales; however, it’s unclear if these interactions persist on longer timescales. Using a compilation of marine archives in the Indo-Pacific, I aim to reconstruct Indo-Pacific sea surface temperatures over the past four centuries to assess these tropical basin interactions on longer timescales.

Tropical Rainbelt Expansion and Contraction

The tropical rainbelt (TRB) is an equatorial band of heavy rainfall associated with the ascending limb of the Hadley Circulation. Historically, hydroclimate proxies in the tropics were interpreted to reflect TRB drift/migration in response to climate forcings. However in recent years, studies have found evidence that the TRB also exhibits expansion and contraction behaviour. Using a pair of stalagmites on the margins of the Austral-Asian TRB, we find evidence of rainbelt width changes over the last millennium. Furthermore utilizing models and additional archives, we propose a dynamical framework for the driver of TRB expansion and contraction.

Glacial Terminations

My past research focused on geochemical analysis of marine sediments from the Southern Ocean, tropical Atlantic, and subpolar North Atlantic in attempts to understand large-scale ocean circulation changes across glacial terminations. I analyzed the elemental and isotopic composition of the marine sediments as well as microfossils within them which led to important insights into ocean circulation and heat-uptake changes in response past climate transitions.