Results are reported from the first long, recording current meter observations over the slope off Chile. These observations, at 30ЊS during the 1991-92 El Nin ˜o event, are analyzed together with observations of currents at a local deep sea site; local wind and sea level; sea level from the Peru and Chile coasts; and wind, temperature, and currents from the equatorial Pacific. Mean poleward flow of 12 cm s Ϫ1 was observed within the Peru-Chile Undercurrent over the slope. Mean flow in the depth range of Antarctic Intermediate Water was not distinguishable from zero in the presence of strong, low-frequency (LF) variability, which dominated slope currents at all depths. The strongest LF fluctuations had periods of about 50 days, but periods of 10 and about 5 days were also observed. Significant, local wind forcing of slope currents was only found in the period band 6-10 days and may be related to coastal-trapped waves in the atmosphere.Our analysis shows that free, coastal-trapped waves in the ocean, arriving from the north, dominated the LF variability over the shelf and slope off northern and central Chile during the 1991-92 El Nin ˜o event. Strong 50-day period fluctuations there started their journey about two months earlier-and 15 000 km farther up the coastal-equatorial waveguide-near the date line in the equatorial Pacific as equatorial Kelvin waves forced by westerly wind events of similar period. Upon reaching the South American coast, these waves forced coastaltrapped waves, which propagated along the Peru coast into the study region. Likewise, a scenario of equatorialtrapped waves forcing coastal-trapped waves may explain 10-day as well as 6-day and 4.5-day period coastaltrapped waves off Chile stemming from mixed Rossby-gravity and inertia-gravity waves trapped at the equator. Since the large, 50-day period, coastal-trapped waves may strongly modify coastal upwelling source water, such remotely forced waves may have a significant influence on the pelagic ecosystem off Chile, at least during El Nin ˜o events.

[1] The subinertial flow on the continental shelf off Concepción (central Chile) and its relation with the local wind-forcing and the topography are studied. Emphasis is placed on the three-dimensional aspects and the effect of the topography on the classical twodimensional approach to the coastal upwelling. Time series coming from 18 current meters installed on six moorings during March-April 1994 were analyzed. Hydrographic data were collected during two hydrographic cruises (6-7 March and 30-31 March). Complementary information includes wind data and sea level. Empirical orthogonal functions using all series showed two principal subinertial flow patterns. The first mode corresponds to an alongshore flow responding to the intensification of southwesterly wind on a 3-to 10-day scale. The second mode is dominated by the cross-shore fluctuations at the shelf break. The importance of the local wind-forcing appears clearly when comparing the theoretical and observed Ekman transport in the north and central shelf (R = 0.8). Near the bottom a mean southward flow was found with a clear southward intensification induced by the bathymetry and probably by a meridional pressure gradient. This bottom flow modifies the typical coastal upwelling pattern through an offshore Ekman transport in the surface and bottom layers. This implies that the compensation flow for the coastal divergence comes from intermediate waters that arrive onto the shelf through ageostrophic process related with the submarine canyons located toward the north and south of the shelf.

Abstract. Seasonal data on temperature, salinity, dissolved oxygen (DO) and chlorophyll, combined with meteorological and river discharge time series, were used to describe the oceanographic conditions of the Reloncaví fjord (41 • 35 S, 72 • 20 W). The winds in the fjord valley mainly blow downfjord during the winter, reinforcing the upper layer outflow, whereas the winds blow predominantly up-fjord during the spring and summer, contrary to the upper layer outflow. The fjord, with a deep sill at the mouth, was well stratified yearround and featured a thin surface layer of brackish water with mean salinities between 10.4 ± 1.4 (spring) and 13.2 ± 2.5 (autumn). The depth of the upper layer changed slightly among the different studied seasons but remained at 4.5 m near the mouth. This upper layer presented a mean outflow (Q 1 ) of 3185 ± 223 m 3 s −1 , which implies a flushing time of 3 days for this layer. The vertical salt flux was ∼ 37 tons of salt per second, similar to the horizontal salt flux observed in the upper layer. These estimates will contribute to better management of the aquaculture in this region.

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