The Gulf of California, a narrow, semienclosed sea, is the only evaporative basin of the Pacific Ocean. As a result of evaporative forcing, salinities in the gulf are 1 to 2 %0 higher than in the adjacent Pacific at the same latitude. This paper examines the thermohaline structure of the gulf and the means by which thermohaline exchange between the Pacific and the gulf occurs, over time scales of months to years. In addition to evaporative forcing, air-sea heat fluxes and momentum fluxes are important to thermohaline circulation in the gulf. From observations presented here, it appears that the gulf gains heat from the atmosphere on an annual average, unlike the Mediterranean and Red seas, which have comparable evaporative forcing. As a result, outflow from the gulf tends to be less dense than inflow from the Pacific. Winds over the gulf change direction with season, blowing northward in summer and southward in winter. This same seasonal pattern appears in near-surface transports averaged across the gulf. The thermohaline circulation, then, consists of outflow mostly between about 50 m and 250 m, inflow mostly between 250 m and 500 m, and a surface layer in which the direction of transport changes with seasonal changes in the large-scale winds. Using hydrographic observations from a section across the central gulf, total transport in or out of the northern gulf is estimated to be 0.9 Sv, heat gain from the atmosphere is estimated to be 20 to 50 W m -2, and evaporation is estimated to be 0.95 m yr -l. These estimates are annual averages, based on cruises from several years. Seasonal variations in thermohaline structure in the gulf are also examined and found to dominate the variance in temperature and density in the top 500 m of the water column. Salinity has little seasonal variability but does exhibit more horizontal variablility than temperature or density. Major year-to-year variations in thermohaline structure may be attributable to E1 Nifio-Southem Oscillation events.

Abstract. An array of shallow pressure gauge pairs is used to determine shallow geostrophic flow relative to an unknown mean velocity in the five principal straits that separate the eastern Indian Ocean from the interior Indonesian seas (Lombok Strait, Sumba Strait, Ombai Strait, Savu/Dao Straits, and Timor Passage). Repeat transects across the straits over several tidal cycles with a 150-kHz acoustic Doppler current profiler were made during three separate years, and provide a first look at the lateral and vertical structure of the upper throughflow in these straits as well as a means of "leveling" the pressure gauge data to determine the mean shallow velocity and provide transport estimates. We estimate a total 2-year average transport for 1996-1997 through Lombok,

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Abstract.Recent IntroductionThe California Current system is traditionally described in terms of three major components: first, the California Current itself, historically held to be a broad, relatively sluggish equa- In the analysis presented here, several aspects of this traditional picture are challenged. First, we find that the synoptic CC just outside the bight (we define the bight as the region east of the Santa Rosa Ridge and including the SB Channel ( Figure 2b)) is neither broad nor sluggish but, rather, tends to be jet-like, as was found during the coastal transition zone (CTZ) experiment off northern California [Brink and Cowles, 1991].Because the CC moves onshore and offshore seasonally, the average picture is a broad, slow feature, but this is not representative of the synoptic current or even of the seasonal average maps. Second, we find that the average geostrophically balanced flow off southern California is divided by the Santa Rosa Ridge, with poleward flow in the bight and equatorward flow offshore, except in spring when an equatorward anomaly weakens or reverses the poleward flow in the bight. Third, we find that wind stress curl over the SC Bight is strong enough and of the right sign to explain the observed poleward flow inshore of the SR Ridge in terms of a Sverdrup balance. In contrast, the observed CC just outside the bight cannot be similarly explained: wind stress curl offshore of the SR Ridge 7695

Five cross‐strait hydrographic sections repeated several times during the Gibraltar Experiment in 1985–1986 are used to examine the structure of the interface layer between the inflowing Atlantic waters and outflowing Mediterranean waters in the Strait of Gibraltar. The interface is 60–100 m thick, with a strong vertical salinity gradient identified by fitting individual salinity profiles to a piecewise‐linear, three‐layer model. The interface is deeper, thicker, fresher, and colder on the west end of the strait than in the Narrows, where there is a minimum in thickness and a maximum in salinity gradient. Farther east, the interface thickens again and continues to get saltier, warmer, and shallower. Property variations in all three layers are also cast in terms of the three principal water types involved in the exchange. The traditional Knudsen model of exchange is extended to three layers, assuming that the interface is a transport‐carrying third layer with uniform vertical shear. As much as half of the inflowing or outflowing transport occurs in the interface layer. Transport converges in both the upper and lower layers, implying, over the length of the strait, vertical exchange between layers that is comparable to about half the horizontal exchange. The richness of structure and complexity of interaction between the interface and the upper and lower layers argues against the use of two‐layer models to characterize exchange through the Strait of Gibraltar.