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[1] A physical model based on determining the fraction of the tidal prism that returns to the estuary on the next high tide is used to estimate the flushing time of the Okatee River estuary. Ra is used to determine the apparent age of water in the estuary. These ages range from 1.6 to 5 days, with an average of 3.4 days. These three independent estimates are in remarkably close agreement, certainly within the error of each estimate. We use these residence times to develop a mass balance model for the radium isotopes in the Okatee estuary. We consider decay, mixing, sedimentary input, river input, and submarine groundwater discharge (SGD). The major loss term for each isotope is mixing with water in Port Royal Sound; the major input for each isotope is SGD. At steady state these terms must balance. Knowing the water age and the radium isotope composition of groundwater entering the Okatee allows us to estimate an average SGD flux of 1 m 3 /s. The SGD flux is a factor of 3-4 greater during the summer relative to the winter. This SGD supplies a considerable quantity of nutrients and carbon into the Okatee system.

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We have calculated an upwelling index for each month over a 17-year period (1969-1985) for a point off the western coast of Spain. We interpret April through September values of the index to indicate the flux of nitrate-rich water into the Spanish Rias. The index representing the 6-month upwelling series has been correlated with an index representing the conditions of mussels grown during that season on rafts in Ria de Arosa. Two seasons represent extreme upwelling conditions over the 17-year sampling period: 1977 when the upwelling index was the highest, and 1983 when it was the lowest. A comparison of the condition of mussels during these years showed that meat content was double in 1977. We suggest, by this study, that long range forecasts of synoptic scale weather patterns could be used to predict the potential nutritional value of mussels harvested in the rias of Spain.

Observations and numerical simulations of upwelling along the Galician coast of Spain during April 1982 are presented. In situ measurements include shipboard determinations of hydrographic and biological parameters from a grid of stations covering the continental shelf from Cape Finisterre to Ria de Vigo, sea level data from Vigo and La Corufia, and wind stress estimates derived from the ship winds and from surface pressure charts. Sea surface temperature information and pigment concentration information have been obtained from a sequence of satellite images from the NOAA 7 advanced very high resolution radiometer and the Nimbus 7 coastal zone color scanner, respectively. Since the Cape Finisterre sector of the Iberian peninsula is characterized by an abrupt change in coastline orientation, wind-driven upwelling can occur in that region over a 270 ø range of wind direction. These data document the evolution of upwelling and the resultant coastal circulation in response to two wind events that occurred over a 10-day period. Salient features of the circulation include a southward coastal jet and a northward flow further offshore along the western coast. Numerical simulations of the coastal currents, the vertical excursion of a density interface from a static equilibrium position, and coastal sea level are conducted using a wind patch characterized by constant direction and negative curl. The simulations show that during these wind events, the greatest upwelling will occur either at Cape Finisterre or along the northern coast as was observed in this case and as has been reported by others. It is suggested on the basis of the analysis of the sea level records and on the numerical simulations that wave disturbances propagate northward along the coast at a speed of 120-160 km/day. Finally, it is speculated that much of the organic material formed during upwelling events north of the Cape Finisterre is advected out to sea northwest of the cape. INTRODUCTION The western coast of the Iberian peninsula is the site of seasonal wind-driven upwelling from March through October [Wooster et al., 1976]. This upwelling is part of a general system that extends southward to about 15øN. Along the Galician coast of Spain (Figure 1), the upwelling is most intense from April to August [Fraga, 1981] with the region between capes Finisterre and Ortegal exhibiting the coldest surface temperatures. During the remainder of the year, the winds are predominantly from the south, or downwelling favorable. The irregular configuration of the Galician coastline and the general circulation of the offshore water masses add complexity to the response of the coastal waters to the wind. For instance, south of Cape Finisterre are five embayments, or rias, which cause enhancement of the upwelling through current-bathymetry interactions [Blanton et al., 1984]. Also, the coastline abruptly ends its north-south orientation at Cape Finisterre and continues in an east-west direction east of Cape Ortegal. Thus upwelling favorable winds span a 270 ø range in di...

Data from 2872 hydrographic stations have been used to determine the oceanographie climatology of the southeastern United States continental shelf waters. The data were sorted by each degree of latitude and by depth into three zones (0–20 m, 21–40 m, 41–60 m). Inner shelf water temperatures were similar to adjacent land air temperatures, while outer shelf temperatures were moderated by the Gulf Stream. Minimum and maximum water temperatures occurred in Georgia and South Carolina inner shelf water. Bottom temperatures were unusually low off Florida in the summer probably because of shelf break upwelling. Surface salinity was lowest adjacent to the rivers and reached minimums in the spring at the time of high runoff. An exception to this occurred in the fall, when strong southward winds apparently advected low salinity coastal water southward and offshore flow was restricted. Heat flux was calculated from changes in monthly mean depth‐averaged inner shelf water temperatures. Heating occurred from March through July with maximum rates of 103 W m−2. Cooling occurred from October through February with maximum rates of −90 W m−2. Bulk stratification was estimated from the difference in near‐surface and near‐bottom monthly mean density. In the spring, stratification increases in inner shelf areas because of decreasing winds and increasing heat flux and runoff. By summer the whole shelf is highly stratified reflecting the contrast between high surface water temperatures and cooler bottom waters. Highest bulk stratification is found over the outer shelf. Stratification decreased with the approach offall with the associated cooling and high winds. Mean flow at midshelf was northward and appears to be produced by an along‐shelf slope of sea level of oceanic origin. Data are available with entire article on microfiche. Order from the American Geophysical Union, 2000 Florida Avenue, N.W. Washington, D.C. 20009. Document C82‐002; $2.50. Payment must accompany order.

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A 1-yr time series of Coastal Zone Color Scanner (CZCS) imagery of continental shelf waters off the southeastern U.S. was statistically analyzed to determine dominant scale lengths in the range from 2 to 100 km for near-surface chlorophyll (Chl) variability. For each image, we extracted two-dimensional matrices of CZCS-Chl concentrations from each of 10 study areas. Variograms (structure functions) were calculated for both the along-and across-shelf dimension of each data matrix, although we designed the study areas to focus on along-shelf variability.The variograms were used to determine whether the images contained nonrandom structure and, if so, to estimate its scale lengths. Outer shelf CZCS-Chl distributions lacked apparent spatial structure in about 50% of the data matrices vs. < 10% for the inner shelf matrices. In general, scale length increased with distance offshore and did not change with season. For example, the mean scale length (n = 30 images) for along-shelf CZCS-Chl variability on the inner shelf off Georgia was 32 km vs. 84 km (n = 18 images) for the outer shelf. WC propose that Gulf Stream frontal eddies are the principal determinants of outer shelf scale length and that topographic effects on the position of a coastal salinity front determine scale length on the inner shelf off Georgia and South Carolina.