Esaias, W. W. NASA/GSFC,

The open ocean transition zone is detectable in ocean color imagery as a region between the oligotrophic subtropical gyres and the seasonally eutrophic subpolar gyres. Its position migrates meridionally 1000 kilometers or more over an annual cycle with the re-distribution of phytoplankton biomass. Documenting the interannual variability in its position is important to understanding the spatial distribution of primary productivity and associated processes over time and has potential application in monitoring the response of oceanic ecosystems to climatic change. The interannual variability in the southern and northern most latitudes attained by the transition zones over an annual cycle in the North Atlantic and North Pacific Oceans from November, 1978 to June, 1986 were documented by locating its position in monthly mean pigment images derived from Coastal Zone Color Scanner data. Climatologically, the transition zone attained its southern most (ca.34N) and northern most (42N/46N) positions in the months of February and August, respectively. The difference between these measurements, which represent the heights of the path traced by the transition zone over an annual cycle, were approximately three degrees of latitude greater in the North Atlantic (12.1 degrees) than in the North Pacific (9.3 degrees). Deviations from these average values were evident in both regions during 1982 - 1983, though some of this variability may be attributable to poor data coverage.
Day: Thursday, Feb. 4
Time: 02:30 - 02:45pm
Location: Eldorado Hotel
Code: CS61TH0230E