Warm ocean anomaly, air sea fluxes, and the rapid intensification of tropical cyclone Nargis (2008)

On 2 May 2008, category-4 tropical cyclone Nargis devastated Myanmar. It was observed that just prior to its landfall, Nargis rapidly intensified from a weak category-1 ;storm to an intense category-4 storm within only 24 h. Using in situ ocean depth-temperature measurements and satellite altimetry, it is found that Nargis' rapid intensification took place on a pre-existing warm ocean anomaly in the Bay of Bengal. In the anomaly, the subsurface ocean is evidently warmer than climatology, as characterized by the depth of the 26 degrees C isotherm of 73-101 m and the tropical cyclone heat potential of 77 105 kj cm(-2). This pre-existing deep, warm subsurface layer leads to reduction in the cyclone-induced ocean cooling, as shown from the ocean mixed layer numerical experiments. As a result, there was a near 300% increase in the air-sea enthalpy flux to support Nargis' rapid intensification. Citation: Lin, I.-I., C.-H. Chen, I.-F. Pun, W. T. Liu, and C.-C. Wu(2009), Warm ocean anomaly, air sea fluxes, and the rapid intensification of tropical cyclone Nargis (2008), Geophys. Res. Lett., 36, L03817, doi: 10.1029/2008GL035815.