Tropical Cyclone Cold Wake Size and Its Applications to Power Dissipation and Ocean Heat Uptake Estimates

Mixing of the upper ocean by the wind field associated with tropical cyclones (TCs) creates observable cold wakes in sea surface temperature and may potentially influence ocean heat uptake. The relationship between cold wake size and storm size, however, has yet to be explored. Here we apply two objective methods to observed daily sea surface temperature data to quantify the size of TC-induced cold wakes. The obtained cold wake sizes agree well with the TC sizes estimated from the QuikSCAT-R wind field database with a correlation coefficient of 0.51 and 0.59, respectively. Furthermore, our new estimate of the total cooling that incorporates the variations in the cold wake size provides improved estimates of TC power dissipation and TC-induced ocean heat uptake. This study thus highlights the importance of cold wake size in evaluating the climatological effects of TCs. Plain Language Summary The wind field of a tropical cyclone can mix warm water downward, leaving a cold wake at the surface. This effect may influence ocean heat uptake within the climate system. We derive a novel oceanic metric of tropical cyclone size based on its induced cold wake using sea surface temperature data for a period from 2002 to 2011. The cold wake size agrees well with the wind field size determined from QuikSCAT surface winds. Furthermore, with the cold wake size incorporated, total cooling provides better quantifications of tropical cyclone power dissipation and cyclone-induced ocean heat uptake. More reliable estimates of cyclone power dissipation and sea surface cooling may be useful for both understanding and forecasting impacts of tropical cyclones on the climate system.