UC San Diego

Cycles of heat transfer between the tropical ocean and atmosphere help drive some of the Planet’s most important modes of climate variability. Subsurface turbulent heat fluxes (Jq) that redistribute ocean heat are known to mediate ocean-atmosphere dynamics at multiple timescales. However, a relative scarcity of observations has slowed down the inclusion of Jq in dynamical frameworks and theories of coupled tropical climate. This dissertation includes three chapters that use in-situ ocean measurements to explore the relations between atmospheric forcing, Jq, and other oceanic variables. Two case studies give special attention to the immediate and long-term ocean response to tropical cyclones (TCs), while a third chapter uses year-long records of Jq to explain their relation to the Asian Monsoon, and interpret their impacts on the seasonality of ocean temperatures in the Western Pacific Warm Pool (WPWP). Overall, the results highlight the importance of atmospheric extremes in regulating Jq and ocean heat uptake by the WPWP and by cold water masses that lay beneath it. Most attention is given to TCs, the near-inertial internal waves (NIWs) they generate, and how NIWs allow TCs to transform ocean currents and thermodynamics for weeks after the storms have dissipated. Besides TCs, it is also emphasized that large scale dynamics can also give rise to atmospheric extremes in which background conditions cause dramatic seasonal shifts in Jq and ocean heat uptake.