Remote sensing of water color and sea surface temperatures off the Oregon coast1

Multispectral scanner measurements from aircraft revealed complicated and often abrupt changes in ocean color which appeared less conservative than changes of sea surface temperature measured with an infrared radiometer, although the general areal patterns were similar. Color and thermal fronts, which often coincided, were most pronounced between upwelled water, Columbia River plume water, and oceanic waters. Normalized spectra of backscattered light in seven bandwidths and differences between specific bands were useful in identifying water types. The blue (0.45–0.47 µ) minus green (0.52–0.55 µ) differences were highest in oceanic water, intermediate in plume water, and low in chlorophyll‐rich upwelled water. The green (0.52–0.55 µ) minus orange (0.58– 0.63 µ) were highest inshore and lowest offshore. Near the mouth of the Columbia River, where water contained a large load of particulate matter, both blue — green and green — orange differences were low. Multiple color bands in the upwelling zone and fronts along both inshore and offshore margins of the Columbia River plume result from dynamic processes that may influence concentrations of pelagic fishes.