Warm ocean anomaly, air sea fluxes, and the rapid intensification of tropical cyclone Nargis (2008)
Abstract
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°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.
- Publication:
-
Geophysical Research Letters
- Pub Date:
- February 2009
- DOI:
- 10.1029/2008GL035815
- Bibcode:
- 2009GeoRL..36.3817L
- Keywords:
-
- Atmospheric Processes: Ocean/atmosphere interactions (0312;
- 4504);
- Atmospheric Processes: Remote sensing;
- Oceanography: Physical: Upper ocean and mixed layer processes