Background
Many and diverse are the studies that have explored both real and imagined impacts of changes in sea surface temperature (SST) on various properties of tropical cyclones (TCs). Much less discussed is the reverse phenomenon of the impacts of TCs on SSTs. It has been known for decades, however - as reported by Dare and McBride - that strong winds associated with TCs tend to reduce SSTs beneath such storms, as described (in chronological order) by Fisher (1958), Leipper (1967), Brand (1971), Price (1981), Bender et al. (1993), Hart et al. (2007), Price et al. (2008), Jansen et al. (2010) and Hart (2011). This cold surface wake, as they describe it, "may extend for hundreds of kilometers adjacent to the storm track (Nelson, 1996; Emanuel, 2001)," and it can spread to larger scales over time, as reported by Sobel and Camargo (2005). As for the SST reduction within the TC wake, Dare and McBride write that it can "range from less than 1°C (Cione et al., 2000), up to 3° (Shay et al., 1991), 4° (Price et al., 2008), 5° (Price, 1981), 6° (Berg, 2002), 7° (Walker et al., 2005), and 9°C (Lin et al., 2003)."

What was done
Using the International Best Track Archive for Climate Stewardship (IBTrACS; Knapp et al., 2009) to provide the latitudes and longitudes at six-hour intervals for all TCs that occurred throughout the world over the period 1 September 1981-31 December 2008, together with a corresponding set of SST data that was provided by NOAA's National Climatic Data Center at every 0.25° of latitude and longitude (Reynolds et al., 2007), the two Australian researchers calculated the mean magnitude of the SST reductions and the average amount of time required for the reduced SSTs to return to pre-storm values.

What was learned
Dare and McBride determined, first of all, that the time of maximum SST cooling occurred one day after cyclone passage, when the SST depression averaged 0.9°C. Thereafter, they report that 44% of the SST depressions returned to normal within 5 days, while 88% of them recovered within 30 days. And although there were differences among individual cyclone basins, they say the individual basin results were in broad agreement with the global mean results. Last of all, they indicate that "cyclones occurring in the first half of the cyclone season disrupt the seasonal warming trend, which is not resumed until 20-30 days after cyclone passage," while they note that "cyclone occurrences in the latter half of the season bring about a 0.5°C temperature drop from which the ocean does not recover due to the seasonal cooling cycle."

What it means
In light of the two scientists' findings, it can be appreciated that each TC that occurs somewhere in the world leaves behind it a significantly altered SST environment that would be expected to have somewhat of a tempering effect on other TCs that might come that way anytime up to as many as 20 to 30 days later.

References
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Berg, R. 2002. Tropical cyclone intensity in relation to SST and moisture variability: A global perspective. Twenty-Fifth Conference on Hurricanes and Tropical Meteorology. American Meteorological Society. Boston, Massachusetts, USA.

Brand, S. 1971. The effects on a tropical cyclone of cooler surface waters due to upwelling and mixing produced by a prior tropical cyclone. Journal of Applied Meteorology 10: 865-874.

Cione, J.J., Molina, P., Kaplan, J. and Black, P.G. 2000. SST time series directly under tropical cyclones: Observations and implications. Twenty-Fourth Conference on Hurricanes and Tropical Meteorology. American Meteorological Society. Boston, Massachusetts, USA.

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Price, J.F., Morzel, J. and Niiler, P.P. 2008. Warming of SST in the cool wake of a moving hurricane. Journal of Geophysical Research 113: 10.1029/2007JC004393.

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Shay, L.K., Black, P.G., Hawkins, J.D., Elsberry, R.L. and Mariano, A.J. 1991. Sea surface temperature response to Hurricane Gilbert. Nineteenth Conference on Hurricanes and Tropical Meteorology. American Meteorological Society. Boston, Massachusetts, USA.

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