Seasonal estimates of oceanic whitecap coverage are presented on global contour maps. The instantaneous fraction of the sea surface covered by whitecaps as a function of wind speed has been described previously using a power law fitting technique <Monahan and Muircheartaigh, 1980>. This relationship, coupled with a Gaussian wind speed frequency distribution, allows us to calculate the oceanic whitecap coverage accounting for the variance about mean wind speeds. We use monthly mean wind speed and variance information in 5¿ latitude ¿5¿ longitude areas over the world ocean to estimate the global oceanic whitecap coverage distribution. The whitecap coverage in the northern hemisphere oceans displays a substantial seasonal dependence. The boreal summer average whitecap coverage in the high-latitude North Atlantic is about 0.5% and increases by a factor of roughly 6 to over 3.6% for a boreal winter average. The whitecap coverage in the high-latitude southern hemisphere oceans exhibits only a factor of 3 difference for the same seasons, from about, 1% in the austral summer to over, 3% for the austral winter. There are several high-latitude areas with greater than, 3% average whitecap coverage over several months of the year. The monsoonal winds in the Indian Ocean result in over 3% mean whitecap coverage for the June--July--August period. |