Variability of pigment biomass in the California Current System as determined by satellite imagery: 2. Temporal variability

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Abstract
Characteristics of temporal variability in the California Current system are analyzed using a 30‐month time series of Coastal Zone Color Scanner (CZCS) imagery. About 20–25% of the variance is produced by a periodic annual cycle with peak values in winter. Analysis of ship‐based chlorophyll measurements indicates that the winter peak is only characteristic of the upper portion of the euphotic zone and that total water column chlorophyll peaks during the spring upwelling season. Satellite studies of intra‐annual variability are modulated by strong 5‐ to 6‐day oscillation in the availability of usable imagery, resulting from a combination of satellite orbital dynamics, which produces images of the study area roughly 4 out every 6 days, and an oscillation in cloud cover, which controls the availability of clear imagery. The cloud cover oscillation, which is also present in coastal winds, undoubtedly affects the ocean surface and biases the data obtained by satellites. Analysis of data using a 5‐day time step indicates that the predominant mode of nonseasonal variability is characterized by inphase fluctuations throughout the southern and central California coastal region.