Climatological atmosphere-ocean response to tropical cyclone passage and the role of turbulent heat fluxes

Several authors have studied the ocean-atmosphere response to a tropical cyclone passage since 1950, and the approach used by them is to analyze the life cycle of a single tropical cyclone, using different sources of information. The reduction of sea surface temperature is one of the relevant aspects of ocean response, usually referred to as Cold Wake. The goal of this study is to find climatological evidence of the cold wake magnitude as a function of the strength of turbulent heat fluxes. We use two kinds of data: the oceanic and atmospheric variables available from the National Data Buoy Center (NDBC) in the period between 1978 and 2017 in the North Atlantic and East Pacific ocean basins, to assess the ocean response to surface forcing, five days before and after the passage of a tropical cyclone, and The International Best Track Archive (IBTrACS) that provides the location and strength of all storms every 6 hours. Two parameters were defined to quantify the SST cooling intensity and its persistence: (i) the local ten-day SST anomaly minimum and (ii) the accumulated SST anomaly in the five days following a storm passage. Also, the turbulent heat fluxes were estimated using the COARE bulk parametrization to assess its relationship with the two previously described parameters. The drag coefficient used is estimated considering strong-wind regime. The results reveal a clear and robust correlation between the intensity of the tropical cyclone and the magnitude of the cold wake in the North Atlantic basin. In the East Pacific basin, we can not conclude the same, most likely due to the lack of a sufficient amount of data. Furthermore, we examine the outliers of the observed relationship as specific cases: intense tropical cyclone with slight SST cooling, and significant SST cooling in cases of weak tropical cyclone passage. These particular cases evidence the relevance of the prior amount of energy lost by the ocean before the tropical cyclone passage. In general, results also suggest a critical role of the magnitude of turbulent heat fluxes before and during tropical cyclone passage in cold wake amplitude