Spatial structures of optical parameters in the California current, as measured with the Nimbus-7 Coastal Zone Color Scanner.

Abstract

Optical variability across the continental slope and shelf off Central California was studied using Nimbus-7 Coastal Zone Color Scanner (CZCS) data. CZCS estimates of It (490), the irradiance attenuation coefficient at 490 nm, were expressed as optical depth 1/k(490). k modified atmospheric correction algorithm was used to account for water radiance at 670 nm. Time sequences of 1/k(490) were assembled and partitioned into four zonal transects, at different latitudes, spanning May through November in 1979, 1980 and 1982. Empirical Orthogonal Functions (EOFs) were calculated for each partition. The first EOFs are dominated by scales of order 180 km, with in all cases, a band of low optical depth water in the first 100 km adjacent to the coast. Scales decrease in successive EOFs, to about 40 km in the fifth EOF. The feasibility of joining EOFs from different partitions was demonstrated as a precursor for future applications to piecewise analysis of oceanic satellite data.