Upper-ocean response to Hurricane Frances (2004) observed by Profiling EM-APEX floats
MetadataShow full item record
Three autonomous profiling Electromagnetic Autonomous Profiling Explorer (EM-APEX) floats were air deployed one day in advance of the passage of Hurricane Frances (2004) as part of the Coupled Boundary Layer Air–Sea Transfer (CBLAST)-High field experiment. The floats were deliberately deployed at locations on the hurricane track, 55 km to the right of the track, and 110 km to the right of the track. These floats provided profile measurements between 30 and 200 m of in situ temperature, salinity, and horizontal velocity every half hour during the hurricane passage and for several weeks afterward. Some aspects of the observed response were similar at the three locations—the dominance of near-inertial horizontal currents and the phase of these currents—whereas other aspects were different. The largest-amplitude inertial currents were observed at the 55-km site, where SST cooled the most, by about 2.2°C, as the surface mixed layer deepened by about 80 m. Based on the time–depth evolution of the Richardson number and comparisons with a numerical ocean model, it is concluded that SST cooled primarily because of shear-induced vertical mixing that served to bring deeper, cooler water into the surface layer. Surface gravity waves, estimated from the observed high-frequency velocity, reached an estimated 12-m significant wave height at the 55-km site. Along the track, there was lesser amplitude inertial motion and SST cooling, only about 1.2°C, though there was greater upwelling, about 25-m amplitude, and inertial pumping, also about 25-m amplitude. Previously reported numerical simulations of the upper-ocean response are in reasonable agreement with these EM-APEX observations provided that a high wind speed–saturated drag coefficient is used to estimate the wind stress. A direct inference of the drag coefficient CD is drawn from the momentum budget. For wind speeds of 32–47 m s−1, CD ~ 1.4 × 10−3.
Author Posting. © American Meteorological Society, 2011. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 41 (2011): 1041–1056, doi:10.1175/2010JPO4313.1.
Showing items related by title, author, creator and subject.
The CBLAST-Hurricane program and the next-generation fully coupled atmosphere–wave–ocean models for hurricane research and prediction Chen, Shuyi S.; Zhao, Wei; Donelan, Mark A.; Price, James F.; Walsh, Edward J. (American Meteorological Society, 2007-03)The record-setting 2005 hurricane season has highlighted the urgent need for a better understanding of the factors that contribute to hurricane intensity, and for the development of corresponding advanced hurricane ...
Ocean–atmosphere dynamics during Hurricane Ida and Nor’Ida : an application of the coupled ocean–atmosphere–wave–sediment transport (COAWST) modeling system Olabarrieta, Maitane; Warner, John C.; Armstrong, Brandy; Zambon, Joseph B.; He, Ruoying (Elsevier B.V., 2011-12-30)The coupled ocean–atmosphere–wave–sediment transport (COAWST) modeling system was used to investigate atmosphere–ocean–wave interactions in November 2009 during Hurricane Ida and its subsequent evolution to Nor’Ida, which ...
Metrics of hurricane-ocean interaction : vertically-integrated or vertically-averaged ocean temperature? Price, James F. (Copernicus Publications on behalf of the European Geosciences Union, 2009-05-05)The ocean thermal field is often represented in hurricane-ocean interaction by a metric termed upper Ocean Heat Content (OHC), the vertical integral of ocean temperature in excess of 26°C. High values of OHC have proven ...