All Climate Events

Thursday, March 28, 2019. 2:00PM. Natural and Anthropogenic Influences on Tropical Cyclones. Christina Patricola, Lawrence Berkeley National Laboratory. Sponsored by NOAA GFDL. More information here.

Tropical cyclones (TCs) are among the costliest and deadliest natural hazards. There are numerous influences on TCs that can originate from the atmosphere and ocean, act constructively or compensate, operate on timescales spanning weather to climate, and arise from natural variability or anthropogenic forcings. Due to this complex set of factors, as well as the limited period of consistent observations, Patricola uses ensembles of convection-permitting regional climate model experiments to uncover causal relationships. Starting with anthropogenic change, Patricola will (1) discuss how the intensity and rainfall of 15 recent destructive TCs could be different if similar events were to occur in pre-industrial and future climates. On the topic of TC variability, they will (2) demonstrate that Atlantic TCs are not limited by their typical precursor (African easterly waves) on the climate timescale, and (3) discuss the influence of the diverse spatial patterns of El Niño’s sea-surface temperature (SST) warming on TCs. Finally, they will (4) present a new index for the El Niño-Southern Oscillation (ENSO) that, for the first time, uniquely captures ENSO’s diversity and extremes and accounts for both the nonlinear response of deep convection to SST and background SST changes associated with the seasonal cycle and climate change. Altogether this research sheds light on the ongoing debate as to whether climate change has yet affected TCs and identifies the utility of potential atmospheric and oceanic sources of seasonal-centennial TC predictability.