Sea Level Anomalies and Hurricane Strength

Walt notices an interesting article in the American Geophysical Union's newsletter, EOS:

Interesting article about hurricanes in EOS, October 4, 2005, by Scharroo et al. They say that sea surface temperature is not the best measure of heat content & hurricane-fueling ability. A high SST might derive from a very thin surface layer with little caloric strength. Rather, sea level altitude, with tides, atmospheric pressure, etc. subtracted out, is better. A dome of high sea level is due to a thick warm layer with lots of heat. They used satellite altimetry data to show how Katrina strengthened over high-sea-level areas.

That is indeed an interesting article: it suggests that one could map in advance where storms might be most likely to intensify. Hurricane Wilma crossed the Loop Current on the way to Florida from Mexico, and also saw an unexpected episode of strengthening.

I wonder how quickly a hurricane can take energy from the underlying water? This article suggests quickly indeed, no doubt assisted by high winds maintaining high temperature/humidity gradients at the surface, but there's bound to be a limit beyond which deep oceanic heat remains essentially unavailable.

I remember first hearing about sea level anomalies associated with oceanic heat. People at the AGU Conference in San Francisco in December, 1986 were talking about the Gulf Stream Wall. At first I laughed, but they were serious, and they looked at me as if I came from Mars for my ignorance. They were oceanographers, though, and I wasn't, and so that explained the knowledge gap. I found it amazing - still do - that such sea level anomalies are routinely measured.