Extended Abstract (360K)JP5.18
Statistical Structure of the Global Ocean Surface Current Speeds from Satellite Altimetry
Peter C. Chu, NPS, Monterey, CA
Near-real time ocean surface currents derived from satellite altimeter (JASON-1, GFO, ENVISAT) and scatterometer data on 1o 1o resolution for world oceans (59.5o S to 59.5o N) posted online as “Ocean Surface Current Analyses – Real Time (OSCAR)”, provide invaluable resources online (http://www.oscar.noaa.gov/index.html) for various uses include large scale climate diagnostics and prediction, fisheries management and recruitment, monitoring debris drift, larvae drift, oil spills, fronts and eddies, plus opportunities for search and rescue, naval and maritime operations.
Statistical analysis was conducted on the OSCAR dataset during 1993-2007. The probability distribution of surface current speeds approximately satisfies the Weibull distribution. The statistical structure of ocean surface current speeds is considered, both in terms of the leading-order moments (mean, standard deviation, skewness, and kurtosis) and in terms of the parameters of a best-fit Weibull distribution. In particular, it is found that the skewness of the ocean surface current speed is a concave upward function of the ratio of the mean current speed to its standard deviation, such that the skewness is positive where the ratio is relatively small, the skewness is close to zero where the ratio is intermediate, and the skewness is negative where the ratio is relatively large. In addition, the seasonal and interannual evolutions of the probability distribution of ocean surface current speeds are characterized. Furthermore, the complex empirical orthogonal function (CEOF) analysis is conducted on the ocean surface current vector (u, v) from the OSCAR data. Many dynamic processes such as the propagation of the Rossby waves and Kelvin waves are identified.
Joint Poster Session 5, Climate
Wednesday, 14 January 2009, 2:30 PM-4:00 PM, Hall 5
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