Variability of pigment biomass in the California Current System as determined by satellite imagery: 1. Spatial variability

Abstract

Spatial variability of chlorophyll in the California Current system was analyzed using Coastal Zone Color Scanner (CZCS) imagery. A total of 48 images were analyzed to produce seasonal averages and variances, gradients, and power spectra. Roughly one third to one half of the variance in pigment biomass can be explained by consistent, large‐scale gradients. In general, biomass is higher in the north and in nearshore areas. Nearshore areas also have proportionally more small‐scale variability than the areas offshore. Slopes of the power spectra for nearshore areas are about −2.2 (for spatial scales of 10–100 km), while slopes for offshore areas are about −3. In addition, the power spectra show evidence of a change in slope at about 10 km, with slopes of about −1 for shorter‐length scales. This may indicate that biological processes dominate the smaller scales, while mesoscale eddies and geostrophic currents dominate the larger scales.