Upwelling off the Gulfs of Panama and Papagayo in the tropical Pacific during March 1985

Abstract

Satellite measurements of sea surface temperatures (SST) were made in the eastern tropical Pacific Ocean during March 1985. Unusually persistent upwelling was observed southwest of the Gulf of Panama and Gulf of Papagayo from March 7 to 22. The SST was depressed by 6° to 10°C relative to the surrounding waters. The cooler waters off Panama extended southwestward for over 1000 km and reached the Galapagos Islands. The northern SST front off Panama was wavelike in appearance, and long waves of 600‐km length moved southwestward at a phase speed of about 30 km/d. These waves resemble the long waves that appear each year along the northern boundaries of the equatorial SST fronts in the Pacific and the Atlantic oceans. The SST fronts off the Gulf of Papagayo remained relatively stationary, with a large area of colder water centered at 88°W and 10°N. During these events, the upwelling off the Gulf of Tehuantepec was relatively weak. These satellite observations provide a view of an unusual oceanic response on the leeward side of mountain pass wind jets.