Climatic Influences on Indian and Pacific Ocean Heat Waves

Thursday, 18 December 2014
Hillary A Scannell, University of Maine, Orono, ME, United States, Matthew H England, University of New South Wales, Sydney, Australia and Alexander Sen Gupta, University of New South Wales, ARC Centre of Excellence for Climate System Science, Sydney, Australia
Large-scale ocean heat waves can be extremely damaging for both ecosystem functioning and fishery productivity. Unlike terrestrial heat waves, little work has been done to understand the dynamics of heat waves in sea surface temperature (SST). New high spatial and temporal resolution SST products now make it possible to investigate regions of persistent extreme anomalies in SST. Here we characterize the properties of Indian and Pacific Ocean heat waves and investigate how they are modulated by the dominant modes of Indo-Pacific climate variability. In particular, we investigate the influence of El Niño/Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) in preconditioning ocean heat waves. For the purposes of this study we define heat waves based on an index of cumulative SST 1ºC above the annual maximum with a geographic extent on the order of 105 square kilometers. We examine the prevalence of ocean heat waves during different phases of ENSO and the IOD, and explore the oceanic and atmospheric processes that give rise to these events.