The development, persistence, and variability of upwelling filaments off the Atlantic coast of the Iberian Peninsula are examined by means of advanced very high resolution radiometer infrared imagery observed between 1982 and 1990. These observations indicate that the regime is broadly similar to that observed in the California Current system and is closely related to the large scale wind climatology of the subtropical gyre. Upwelling generally starts in late May or early June and persists until late September or early October. In May or June, a narrow band of cold water of quite uniform width is observed along much of the west coast of the Iberian Peninsula. This band has a “fringed” appearance; that is it consists of many narrow “fingers” of cool water extending 20–30 km offshore. The major filament structures generally do not begin to form until late July or August. The filaments appear first as bulges in the upwelling front. These bulges grow offshore to form filaments that reach their maximum length (200–250 km) in September. The lengths of the filaments gradually decrease until the filaments become relatively rare in late October.Typically, five or six fully developed filaments are observed off the Iberian Peninsula late in the upwelling season. Most of these are associated with major topographic features of the region, in particular the large capes which are common to the north and south of the peninsula. It is therefore postulated that the dominant dynamical processes related to filament formation off Iberia is topographic forcing. The exceptions are two major filaments commonly observed along the more regular coastline of northern Portugal. It is hypothesized that these filaments are formed by flow instabilities resulting in meandering of the southward flowing jet. These instabilities may possibly be initiated by the large capes of northern Spain.

The seasonal variations and the interactions of the water masses in the tropical Pacific off central Mexico (TPCM) and four surrounding areas were examined based on an extensive new hydrographic database. The regional water masses were redefined in terms of absolute salinity (S_A) and conservative temperature (Θ) according to the Thermodynamic Equation of Seawater 2010 (TEOS-10). Hydrographic data and the evaporation minus (precipitation + runoff) balance were used to investigate the origin and seasonality of two salinity minima in the area. The shallow (50–100 m) salinity minimum originates with the California Current System and becomes saltier as it extends southeastward and mixes with tropical subsurface waters while the surface salinity minimum extends farther north in the TPCM in summer and fall because of the northward advection of tropical surface waters. The interactions between water masses allow a characterization of the seasonal pattern of circulation of the Mexican Coastal Current (MCC), the tropical branch of the California Current, and the flows through the entrance of the Gulf of California. The seasonality of the MCC inferred from the distribution of the water masses largely coincides with the geostrophic circulation forced by an annual Rossby wave.

Since the early surveys carried out by the Eastern Tropical Pacific (EASTROPIC) and Scripps Tuna Oceanographic Research (STOR) projects in the tropical Pacific off Mexico, the northerly winds which blow over the Gulf of Tehuantepec were described as an important factor controlling the dynamics of this coastal ocean. In January–February 1989 an international team carried out the experiment Tehuano, designed to study the response of the gulf to these wind pulses. The complete evolution of the coastal ocean after an event of moderate intensity was observed. The forcing is characterized by a mostly symmetric, fanshaped, offshore wind jet, which in turn produces a remarkably asymmetric upper ocean response. While analytical results based on Ekman theory forced by a symmetric offshore wind predict the formation of a symmetric dipolar circulation, the observed flow consists mainly of a large (200 km in diameter) anticyclonic warm‐core eddy in the western gulf, with only a weak cyclonic counterpart in the eastern gulf. Intense surface cooling under the wind jet is caused by entrainment of subsurface water into the upper layer. The thermocline in the west deepens with the development of the eddy, which is formed initially by the advection of warm surface waters from west of the gulf. East of the axis of the wind, the mixed layer deepens due to wind‐induced entrainment, while, at the same time, shoaling and compression of the deeper isotherms by curl‐induced upwelling (Ekman pumping) strengthen the thermocline.