An overview is given of the upper ocean geopotential height, zonal flow, thermohaline, oxygen, and nutrient structures between the Bering Sea and Fiji islands, based on high-resolution field measurements along 179 ¿E. The geopotential topography is dominated by large-amplitude (2--4 J kg-1) mesoscale perturbations in the subarctic and subtropical gyres and a smoother equatorial ridge-trough system. The fastest midlatitude zonal flows (40 cm s-1) are associated with the Alaska Stream, the Subarctic Current, the Kuroshio Extension, and the North Equatorial Current. Prominent physical and chemical frontal zones are observed between 42¿--45 ¿N and 12¿--15 ¿N. A pronounced upwelling dome is found south of the Aleutians, which brings dense, nutrient rich waters within 125 m of the sea surface. Well-defined upwelling domes also occur in the northern (5¿--10 ¿N) and southern (3¿--8 ¿S) doldrums. El Ni¿o conditions prevailed near the equator in August 1993, marked by surface temperatures of 30 ¿C, low salinities, low nutrient concentrations, eastward surface flow (30 cm s-1), merging of the North Equatorial Countercurrent and Equatorial Undercurrent (50 cm s-1), absence of trade winds and abundant rainfall, and southward displacement of the South Equatorial Countercurrent (20 cm s-1). The South Equatorial Current (20 cm s-1) has a complex multicore structure and is accompanied by a major physical and chemical frontal zone between 13¿--16 ¿S. A fast coastal eastward jet is observed on the north slope of Vanua Levu island, Fiji. ¿ 1998 American Geophysical Union