Skewness of sea level variability of the world's oceans

Abstract

Skewness of sea level variability for the world's oceans is calculated using gridded altimeter data for the period 1993-2001. Many well-known ocean features can be identified in the skewness map, including the Gulf Stream, Kuroshio Extension, Brazil-Malvinas Confluence, and the Agulhas Retroflection. It is shown, through an idealized example and results from a quasi-geostrophic model, that sea level skewness can be used to identify the mean path of unstable ocean jets and also regions dominated by eddies with a preferred sense of rotation. These ideas are confirmed with a more detailed analysis of the skewness fields for the northwest Atlantic and Agulhas Retroflection region. Finally, it is argued that sea level skewness, like variance, is a potentially powerful diagnostic for testing the realism of high-resolution ocean circulation models. Copyright 2006 by the American Geophysical Union.