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• 21. [Article] Upper ocean thermohaline fields near 2°S, 156°E, during the Tropical Ocean-Global Atmosphere - Coupled Ocean-Atmosphere Response Experiment, November 1992 to February 1993

  Zonal and meridional Seasoar sections centered at 1°50’S, 156°06’E were repeated >30 times in three 20-day periods between November 13, 1992, and February 15, 1993. Both sections were 130 km long, and ...

  Citation × Citation Citation Abstract Copy Title: Upper ocean thermohaline fields near 2°S, 156°E, during the Tropical Ocean-Global Atmosphere - Coupled Ocean-Atmosphere Response Experiment, November 1992 to February 1993 Author: Hacker, Peter, Lukas, Roger, Huyer, Adriana, 1945-, Kosro, P. Michael, 1951- Zonal and meridional Seasoar sections centered at 1°50’S, 156°06’E were repeated >30 times in three 20-day periods between November 13, 1992, and February 15, 1993. Both sections were 130 km long, and sampling depth was 0–280 m, with a vertical resolution of ~2 dbar (2 x 104 Pa) and a horizontal resolution of ~3 km. The observed fields are complex and variable and are summarized graphically in several forms. Characteristics of the near-surface layer varied with the local winds which were variable and weak (<6 m s-1) during the first 20-day period, strong and westerly (>10 m s-1) during much of the second, and moderate and westerly (4-10 m s-1) during most of the third. Near-surface temperatures were warmest (up to 30°C) during the first period and coldest (often <29°C) during the second. Thermal stratification in the near-surface layer was strong under weak winds and weak under strong and moderate winds. Except during and after heavy rainfall, salinity stratification in the near-surface layer was generally weak. Surface salinity generally decreased toward the north. The depth of the surface isopycnal layer was often but not always limited by salinity stratification; the surface isohaline layer was shallower than the top of the thermocline throughout. Strong lateral temperature and salinity gradients occurred on a few occasions. Increased wind stress was associated with lateral homogenization as well as vertical mixing. Structure and water properties of the thermocline also varied between cruises and within each cruise. The upper thermocline was shallowest in late January after prolonged easterly winds. Isotherms in the upper and midthermocline (20°–25°C) sloped generally upward to the north, while those in the lower thermocline (12°–14°C) sloped down to envelop the core of the Equatorial Undercurrent, which shoaled (from 225 to 160 m) and warmed (from 15° to 20°C) between the first and last survey periods. Mesoscale and fine-scale water mass features were usually recognizable in sections less than a few days apart and migrated eastward at about 0.3 m s-1. There is a remarkably high degree of nonstationarity in these thermohaline fields from the Warm Pool of the western Pacific Ocean. Title: Upper ocean thermohaline fields near 2°S, 156°E, during the Tropical Ocean-Global Atmosphere - Coupled Ocean-Atmosphere Response Experiment, November 1992 to February 1993 Author: Hacker, Peter, Lukas, Roger, Huyer, Adriana, 1945-, Kosro, P. Michael, 1951- Zonal and meridional Seasoar sections centered at 1°50’S, 156°06’E were repeated >30 times in three 20-day periods between November 13, 1992, and February 15, 1993. Both sections were 130 km long, and sampling depth was 0–280 m, with a vertical resolution of ~2 dbar (2 x 104 Pa) and a horizontal resolution of ~3 km. The observed fields are complex and variable and are summarized graphically in several forms. Characteristics of the near-surface layer varied with the local winds which were variable and weak (<6 m s-1) during the first 20-day period, strong and westerly (>10 m s-1) during much of the second, and moderate and westerly (4-10 m s-1) during most of the third. Near-surface temperatures were warmest (up to 30°C) during the first period and coldest (often <29°C) during the second. Thermal stratification in the near-surface layer was strong under weak winds and weak under strong and moderate winds. Except during and after heavy rainfall, salinity stratification in the near-surface layer was generally weak. Surface salinity generally decreased toward the north. The depth of the surface isopycnal layer was often but not always limited by salinity stratification; the surface isohaline layer was shallower than the top of the thermocline throughout. Strong lateral temperature and salinity gradients occurred on a few occasions. Increased wind stress was associated with lateral homogenization as well as vertical mixing. Structure and water properties of the thermocline also varied between cruises and within each cruise. The upper thermocline was shallowest in late January after prolonged easterly winds. Isotherms in the upper and midthermocline (20°–25°C) sloped generally upward to the north, while those in the lower thermocline (12°–14°C) sloped down to envelop the core of the Equatorial Undercurrent, which shoaled (from 225 to 160 m) and warmed (from 15° to 20°C) between the first and last survey periods. Mesoscale and fine-scale water mass features were usually recognizable in sections less than a few days apart and migrated eastward at about 0.3 m s-1. There is a remarkably high degree of nonstationarity in these thermohaline fields from the Warm Pool of the western Pacific Ocean. Close

• 22. [Article] Currents and water masses of the coastal transition zone off Northern California, June to August 1988

  In summer 1988, we made repeated mesoscale surveys of a grid extending 200 km offshore between 37°N and 39°N in the coastal transition zone off northern California, obtaining continuous acoustic Doppler ...

  Citation × Citation Citation Abstract Copy Title: Currents and water masses of the coastal transition zone off Northern California, June to August 1988 Author: Ramp, Steven R., Washburn, Libe, Cowles, Timothy J., Fleischbein, Jane, Stanton, Tim, Huyer, Adriana, 1945-, Kosro, P. Michael, 1951-, Smith, Robert L. (Robert Lloyd), 1935-, Pierce, Stephen D., Chavez, Francisco P. In summer 1988, we made repeated mesoscale surveys of a grid extending 200 km offshore between 37°N and 39°N in the coastal transition zone off northern California, obtaining continuous acoustic Doppler current profiler data and conductivity-temperature-depth data at standard stations 25 km apart on alongshore sections 40 km apart. All surveys showed a baroclinic equatorward jet, with core velocities of >50 cm/s at the surface decreasing to about 10 cm/s at 200m , a width of 50-75 km, and a baroclinic transporotf about4 Sv. The core of the jet lay between the 8.6 and9 .4 m²/s² contours of geopotential anomaly (relative to 500 dbar). Three current meter moorings, deployed at 25-km separation across the jet at the beginning of the survey sequence, provided time-series of the velocity; throughout the 37-day deployment, at least one mooring was within the core defined by the 8.6 and9 .4 m²/s² contours. The jet flowed southwestward across the grid from late June until mid-July 1988, when the jet axis moved offshore in the north and onshore in the southern portion of the grid. Temperature-salinity analysis shows that jet waters can be distinguished from both the freshly upwelled coastal waters and the offshore waters. Isopycnal maps indicate alongshore advection of relatively fresh, cool water from farther north, as well as small-scale patchiness not resolved by our survey grid. The baroclinic jet observed here may be continuous with the core of the California Current off central California. The later surveys clearly showed a poleward-flowing undercurrent adjacent to the continental slope, with core velocities up to 20 cm/s at depths of 150-250 m. Its baroclinic transport (relative to 500 dbar) increased from <0.5 Sv to >1.0 Sv between late June and early August 1988. Within the survey grid, there was a definite onshore gradient in the characteristics of North Pacific Intermediate Water. The subsurface waters adjacent to the continental margin were warmer and more saline than those offshore, indicating net northward advection by the California Undercurrent over the inshore 100 km and equatorward advection farther from shore. Title: Currents and water masses of the coastal transition zone off Northern California, June to August 1988 Author: Ramp, Steven R., Washburn, Libe, Cowles, Timothy J., Fleischbein, Jane, Stanton, Tim, Huyer, Adriana, 1945-, Kosro, P. Michael, 1951-, Smith, Robert L. (Robert Lloyd), 1935-, Pierce, Stephen D., Chavez, Francisco P. In summer 1988, we made repeated mesoscale surveys of a grid extending 200 km offshore between 37°N and 39°N in the coastal transition zone off northern California, obtaining continuous acoustic Doppler current profiler data and conductivity-temperature-depth data at standard stations 25 km apart on alongshore sections 40 km apart. All surveys showed a baroclinic equatorward jet, with core velocities of >50 cm/s at the surface decreasing to about 10 cm/s at 200m , a width of 50-75 km, and a baroclinic transporotf about4 Sv. The core of the jet lay between the 8.6 and9 .4 m²/s² contours of geopotential anomaly (relative to 500 dbar). Three current meter moorings, deployed at 25-km separation across the jet at the beginning of the survey sequence, provided time-series of the velocity; throughout the 37-day deployment, at least one mooring was within the core defined by the 8.6 and9 .4 m²/s² contours. The jet flowed southwestward across the grid from late June until mid-July 1988, when the jet axis moved offshore in the north and onshore in the southern portion of the grid. Temperature-salinity analysis shows that jet waters can be distinguished from both the freshly upwelled coastal waters and the offshore waters. Isopycnal maps indicate alongshore advection of relatively fresh, cool water from farther north, as well as small-scale patchiness not resolved by our survey grid. The baroclinic jet observed here may be continuous with the core of the California Current off central California. The later surveys clearly showed a poleward-flowing undercurrent adjacent to the continental slope, with core velocities up to 20 cm/s at depths of 150-250 m. Its baroclinic transport (relative to 500 dbar) increased from <0.5 Sv to >1.0 Sv between late June and early August 1988. Within the survey grid, there was a definite onshore gradient in the characteristics of North Pacific Intermediate Water. The subsurface waters adjacent to the continental margin were warmer and more saline than those offshore, indicating net northward advection by the California Undercurrent over the inshore 100 km and equatorward advection farther from shore. Close

• 23. [Article] Two coastal upwelling domains in the northern California Current system

  A pair of hydrographic sections, one north and one south of Cape Blanco at 42.9N, was sampled in five summers (1998–2000 and 2002–2003). The NH line at 44.6N lies about 130 km south of the Columbia River, ...

  Citation × Citation Citation Abstract Copy Title: Two coastal upwelling domains in the northern California Current system Author: Wheeler, Patricia A., Smith, Robert L. (Robert Lloyd), 1935-, Perlin, Natalie, Keister, Julie Eileen, Huyer, Adriana, 1945-, Kosro, P. Michael, 1951-, Fleischbein, Jane A pair of hydrographic sections, one north and one south of Cape Blanco at 42.9N, was sampled in five summers (1998–2000 and 2002–2003). The NH line at 44.6N lies about 130 km south of the Columbia River, and spans a relatively wide shelf off Newport, Oregon. The CR line at 41.9N off Crescent City, California, lies 300 km farther south and spans a narrower shelf. Summer winds are predominantly southward in both locations but the southward winds are stronger on the CR line. Sampling included CTD/rosette casts (to measure temperature, salinity, dissolved oxygen, nutrients, chlorophyll), zooplankton net tows and continuous operation of an Acoustic Doppler Current Profiler. We summarize and compare July-August observations from the two locations. We find significant summer-season differences in the coastal upwelling domains north and south of Cape Blanco. Compared to the domain off Newport, the domain off Crescent City has a more saline, cooler, denser and thicker surface mixed layer, a wider coastal zone inshore of the upwelling front and jet, higher nutrient concentrations in the photic zone and higher phytoplankton biomass. The southward coastal jet lies near the coast (about 20–30 km offshore, over the shelf) on the NH line, but far from shore (about 120 km) on the CR line; a weak secondary jet lies near the shelf-break (35 km from shore) off Crescent City. Phytoplankton tend to be light-limited on the CR line and nutrient-limited on the NH line. Copepod biomass is high (15 mg C m-3) inshore of the mid-shelf on both NH and CR lines, and is also high in the core of the coastal jet off Crescent City. The CR line shows evidence of deep chlorophyll pockets that have been subducted from the surface layer. We attribute these significant differences to stronger mean southward wind stress over the southern domain, to strong small-scale wind stress curl in the lee of Cape Blanco, and to the reduced influence of the Columbia River discharge in this region. Title: Two coastal upwelling domains in the northern California Current system Author: Wheeler, Patricia A., Smith, Robert L. (Robert Lloyd), 1935-, Perlin, Natalie, Keister, Julie Eileen, Huyer, Adriana, 1945-, Kosro, P. Michael, 1951-, Fleischbein, Jane A pair of hydrographic sections, one north and one south of Cape Blanco at 42.9N, was sampled in five summers (1998–2000 and 2002–2003). The NH line at 44.6N lies about 130 km south of the Columbia River, and spans a relatively wide shelf off Newport, Oregon. The CR line at 41.9N off Crescent City, California, lies 300 km farther south and spans a narrower shelf. Summer winds are predominantly southward in both locations but the southward winds are stronger on the CR line. Sampling included CTD/rosette casts (to measure temperature, salinity, dissolved oxygen, nutrients, chlorophyll), zooplankton net tows and continuous operation of an Acoustic Doppler Current Profiler. We summarize and compare July-August observations from the two locations. We find significant summer-season differences in the coastal upwelling domains north and south of Cape Blanco. Compared to the domain off Newport, the domain off Crescent City has a more saline, cooler, denser and thicker surface mixed layer, a wider coastal zone inshore of the upwelling front and jet, higher nutrient concentrations in the photic zone and higher phytoplankton biomass. The southward coastal jet lies near the coast (about 20–30 km offshore, over the shelf) on the NH line, but far from shore (about 120 km) on the CR line; a weak secondary jet lies near the shelf-break (35 km from shore) off Crescent City. Phytoplankton tend to be light-limited on the CR line and nutrient-limited on the NH line. Copepod biomass is high (15 mg C m-3) inshore of the mid-shelf on both NH and CR lines, and is also high in the core of the coastal jet off Crescent City. The CR line shows evidence of deep chlorophyll pockets that have been subducted from the surface layer. We attribute these significant differences to stronger mean southward wind stress over the southern domain, to strong small-scale wind stress curl in the lee of Cape Blanco, and to the reduced influence of the Columbia River discharge in this region. Close

• 24. [Article] The structure of the transition zone between coastal waters and the open ocean off northern California, winter and spring 1987

  Physical and biological fields in the coastal transition zone off northern California were measured during February, March, May and June 1987 in an extended alongshore region between 60 km and 150 km offshore. ...

  Citation × Citation Citation Abstract Copy Title: The structure of the transition zone between coastal waters and the open ocean off northern California, winter and spring 1987 Author: Chavez, F. P., Barber, R. T., Strub, P. Ted, Smith, Robert L. (Robert Lloyd), 1935-, Abbott, Mark R., Cowles, Timothy J., Jessen, P., Ramp, S. R., Huyer, Adriana, 1945-, Kosro, P. Michael, 1951-, Small, Lawrence F. Physical and biological fields in the coastal transition zone off northern California were measured during February, March, May and June 1987 in an extended alongshore region between 60 km and 150 km offshore. The spring transition, as seen in coastal sea level and winds, occurred in mid-March. Surface variability during the two spring cruises was stronger and of larger scale than that seen during the two winter cruises. An equatorward-tending current, flowing along the boundary between low steric sea level inshore and high steric sea level offshore, dominated both the directly-measured (acoustic Doppler current profiler) and geostrophic current fields during spring. Current jets of comparable strength directed both offshore and onshore were seen off Cape Mendocino and Point Arena; these evolved significantly in the 3 weeks between cruises. Inshore of the current, properties associated with upwelled water were found near the surface, including low temperature and high salinity, nutrients and chlorophyll; offshore of the current, waters were warmer, less saline, lower in nutrients and more oligotrophic. Geostrophic and directly measured volume transports in the current were about 2–3 Sv. Isopycnals inshore of the spring upwelling front were displaced vertically by O(40–80 m) from their depths during the winter survey; these displacements extended deep into the water column and were largely independent of depth between 100 and 400 m. Surface mixed layers tended to be deep in winter and shallower inshore of the upwelling front in spring. A connection between the equatorward-tending frontal jet off northern California and the more well-studied California Current further south is suggested by the similarity of their transports and of their dynamic height values. Title: The structure of the transition zone between coastal waters and the open ocean off northern California, winter and spring 1987 Author: Chavez, F. P., Barber, R. T., Strub, P. Ted, Smith, Robert L. (Robert Lloyd), 1935-, Abbott, Mark R., Cowles, Timothy J., Jessen, P., Ramp, S. R., Huyer, Adriana, 1945-, Kosro, P. Michael, 1951-, Small, Lawrence F. Physical and biological fields in the coastal transition zone off northern California were measured during February, March, May and June 1987 in an extended alongshore region between 60 km and 150 km offshore. The spring transition, as seen in coastal sea level and winds, occurred in mid-March. Surface variability during the two spring cruises was stronger and of larger scale than that seen during the two winter cruises. An equatorward-tending current, flowing along the boundary between low steric sea level inshore and high steric sea level offshore, dominated both the directly-measured (acoustic Doppler current profiler) and geostrophic current fields during spring. Current jets of comparable strength directed both offshore and onshore were seen off Cape Mendocino and Point Arena; these evolved significantly in the 3 weeks between cruises. Inshore of the current, properties associated with upwelled water were found near the surface, including low temperature and high salinity, nutrients and chlorophyll; offshore of the current, waters were warmer, less saline, lower in nutrients and more oligotrophic. Geostrophic and directly measured volume transports in the current were about 2–3 Sv. Isopycnals inshore of the spring upwelling front were displaced vertically by O(40–80 m) from their depths during the winter survey; these displacements extended deep into the water column and were largely independent of depth between 100 and 400 m. Surface mixed layers tended to be deep in winter and shallower inshore of the upwelling front in spring. A connection between the equatorward-tending frontal jet off northern California and the more well-studied California Current further south is suggested by the similarity of their transports and of their dynamic height values. Close

• 25. [Article] CTD and velocity surveys of seaward jets off Northern California, July 1981 and 1982

  Two mesoscale surveys were conducted (in July 1981 and July 1982) near Point Arena, California, to determine the structure and circulation associated with tongues of cold surface water extending seaward from ...

  Citation × Citation Citation Abstract Copy Title: CTD and velocity surveys of seaward jets off Northern California, July 1981 and 1982 Author: Huyer, Adriana, 1945-, Kosro, P. Michael, 1951- Two mesoscale surveys were conducted (in July 1981 and July 1982) near Point Arena, California, to determine the structure and circulation associated with tongues of cold surface water extending seaward from the coastal zone. Both surveys were designed at sea on the basis of available satellite IR data, and each was completed in less than a week. Sampling extended 100 km alongshore and 150 km (1981) to 250 km (1982) offshore, and included conductivity, temperature, and depth casts to 500 dbar, and continuous ocean current profiling to 150 m by means of a Doppler acoustic log. Both surveys showed that the tongues of cold water seen in the satellite images were the surface manifestation of hydrographic and current anomalies that extended to a depth of at least 100 m. In each case, strong seaward flow was observed along the northern edge of the cold tongue, which also marked a shallow water mass boundary between low-salinity (< 32.8 ppt) surface waters to the north and high-salinity (> 33.2 ppt) waters to the south. The seaward jets were very strong (up to 80 cm/s) and narrow (30 km), with strong shears (up to 10- 2 S- 1 in the vertical and up to 10^(-4)/s in the horizontal). They were largely geostrophic, had transports exceeding 1.5 sverdrups, and can persist for 2-3 weeks. The seaward jets seemed to be continuous with southward flowing alongshore coastal jets. There is evidence that the seaward jets are recurrent features in the vicinity of Point Arena. Title: CTD and velocity surveys of seaward jets off Northern California, July 1981 and 1982 Author: Huyer, Adriana, 1945-, Kosro, P. Michael, 1951- Two mesoscale surveys were conducted (in July 1981 and July 1982) near Point Arena, California, to determine the structure and circulation associated with tongues of cold surface water extending seaward from the coastal zone. Both surveys were designed at sea on the basis of available satellite IR data, and each was completed in less than a week. Sampling extended 100 km alongshore and 150 km (1981) to 250 km (1982) offshore, and included conductivity, temperature, and depth casts to 500 dbar, and continuous ocean current profiling to 150 m by means of a Doppler acoustic log. Both surveys showed that the tongues of cold water seen in the satellite images were the surface manifestation of hydrographic and current anomalies that extended to a depth of at least 100 m. In each case, strong seaward flow was observed along the northern edge of the cold tongue, which also marked a shallow water mass boundary between low-salinity (< 32.8 ppt) surface waters to the north and high-salinity (> 33.2 ppt) waters to the south. The seaward jets were very strong (up to 80 cm/s) and narrow (30 km), with strong shears (up to 10- 2 S- 1 in the vertical and up to 10^(-4)/s in the horizontal). They were largely geostrophic, had transports exceeding 1.5 sverdrups, and can persist for 2-3 weeks. The seaward jets seemed to be continuous with southward flowing alongshore coastal jets. There is evidence that the seaward jets are recurrent features in the vicinity of Point Arena. Close

• 26. [Article] Statistical properties of near surface currents in the California coastal transition zone

  During the summers of 1987 and 1988, 77 near-surface satellite-tracked drifters were deployed in or near cold filaments near Point Arena, California (39ºN), and tracked for up to 6 months as part of the ...

  Citation × Citation Citation Abstract Copy Title: Statistical properties of near surface currents in the California coastal transition zone Author: Beardsley, R. C., Abbott, Mark R., Stanton, T., Stuart, D., Ramp, S., Brink, K. H., Niiler, Pearn P., Huyer, Adriana, 1945- During the summers of 1987 and 1988, 77 near-surface satellite-tracked drifters were deployed in or near cold filaments near Point Arena, California (39ºN), and tracked for up to 6 months as part of the Coastal Transition Zone (CTZ) program. The drifters had large drogues centered at 15 m, and the resulting drifter trajectory data set has been analyzed in terms of its Eulerian and Lagrangian statistics. The CTZ drifter results show that the California Current can be characterized in summer and fall as a meandering coherent jet which on average flows southward to at least 30ºN, the southern end of the study domain. From 39ºN south to about 33ºN, the typical core velocities are of O(300 km) and the current meanders have alongshore wavelengths of O(100–200 km) and onshore-offshore amplitude of O(100–200 km). The lateral movement of this jet leads to large eddy kinetic energies and large eddy diffusivities, especially north of 36ºN. The initial onshore-offshore component of diffusivity is always greater than the alongshore component in the study domain, but at the southern end, the eddy diffusivity is more isotropic, with scalar single particle diffusivity (Kxx + Kyy) of O(8 x 107 cm2 s-1). The eddy diffusivity increases with increasing eddy energy. Finally, a simple volume budget for the 1988 filament observed near 37ºN off Point Arena suggests that subduction can occur in a filament at an average rate of O(10 m d-1) some 200 km offshore, thus allowing the cold water initially in the filament core to sink below the warmer ambient water by the time the surface velocity core has turned back onshore. This process explains why satellite temperature and color imagery tend to “see” only flow proceeding offshore. Title: Statistical properties of near surface currents in the California coastal transition zone Author: Beardsley, R. C., Abbott, Mark R., Stanton, T., Stuart, D., Ramp, S., Brink, K. H., Niiler, Pearn P., Huyer, Adriana, 1945- During the summers of 1987 and 1988, 77 near-surface satellite-tracked drifters were deployed in or near cold filaments near Point Arena, California (39ºN), and tracked for up to 6 months as part of the Coastal Transition Zone (CTZ) program. The drifters had large drogues centered at 15 m, and the resulting drifter trajectory data set has been analyzed in terms of its Eulerian and Lagrangian statistics. The CTZ drifter results show that the California Current can be characterized in summer and fall as a meandering coherent jet which on average flows southward to at least 30ºN, the southern end of the study domain. From 39ºN south to about 33ºN, the typical core velocities are of O(300 km) and the current meanders have alongshore wavelengths of O(100–200 km) and onshore-offshore amplitude of O(100–200 km). The lateral movement of this jet leads to large eddy kinetic energies and large eddy diffusivities, especially north of 36ºN. The initial onshore-offshore component of diffusivity is always greater than the alongshore component in the study domain, but at the southern end, the eddy diffusivity is more isotropic, with scalar single particle diffusivity (Kxx + Kyy) of O(8 x 107 cm2 s-1). The eddy diffusivity increases with increasing eddy energy. Finally, a simple volume budget for the 1988 filament observed near 37ºN off Point Arena suggests that subduction can occur in a filament at an average rate of O(10 m d-1) some 200 km offshore, thus allowing the cold water initially in the filament core to sink below the warmer ambient water by the time the surface velocity core has turned back onshore. This process explains why satellite temperature and color imagery tend to “see” only flow proceeding offshore. Close

• 27. [Article] Observations of the coastal upwelling region off Oregon during 1972

  Observations of wind, currents, sea level and hydrography obtained during the 1972 Coastal Upwelling Experiment (CUE-I) are described. Only phenomena with periods longer than a day are considered. One ...

  Citation × Citation Citation Abstract Copy Title: Observations of the coastal upwelling region off Oregon during 1972 Author: Huyer, Adriana, 1945- Observations of wind, currents, sea level and hydrography obtained during the 1972 Coastal Upwelling Experiment (CUE-I) are described. Only phenomena with periods longer than a day are considered. One section describes the changes observed during a period of variable winds in early July 1972. Another describes a ribbon of relatively cool water observed early in the upwelling season and attributes its existence to advection of Subarctic water by the coastal jet associated with upwelling. A third section describes the seasonal development of the upwelling regime between April and October 1972. These studies are combined with other studies of CUE-I data to provide a partial description of the upwelling regime which is compared to the conceptual model developed prior to CUE-I. It is concluded that the vertical and onshore velocity fields are as yet largely unknown. The alongshore velocity field includes southward surface flow with a coastal jet, a persistent vertical shear with deeper velocities northward relative to the surface and high coherence with the wind and sea level at periods of several days. A poleward undercurrent is observed, but it may not be an integral part of the upwelling regime. The hydrography has a strong seasonal cycle. Differences between any two sections between April and October l972 are smaller than between any of these and a section occupied in January 1973. Oscillations in the wind with periods of several days cause significant changes in the region inshore of 10 km and in the upper 20 m further offshore. Subsurface temperature observations are not coherent with the wind at periods of several days. Title: Observations of the coastal upwelling region off Oregon during 1972 Author: Huyer, Adriana, 1945- Observations of wind, currents, sea level and hydrography obtained during the 1972 Coastal Upwelling Experiment (CUE-I) are described. Only phenomena with periods longer than a day are considered. One section describes the changes observed during a period of variable winds in early July 1972. Another describes a ribbon of relatively cool water observed early in the upwelling season and attributes its existence to advection of Subarctic water by the coastal jet associated with upwelling. A third section describes the seasonal development of the upwelling regime between April and October 1972. These studies are combined with other studies of CUE-I data to provide a partial description of the upwelling regime which is compared to the conceptual model developed prior to CUE-I. It is concluded that the vertical and onshore velocity fields are as yet largely unknown. The alongshore velocity field includes southward surface flow with a coastal jet, a persistent vertical shear with deeper velocities northward relative to the surface and high coherence with the wind and sea level at periods of several days. A poleward undercurrent is observed, but it may not be an integral part of the upwelling regime. The hydrography has a strong seasonal cycle. Differences between any two sections between April and October l972 are smaller than between any of these and a section occupied in January 1973. Oscillations in the wind with periods of several days cause significant changes in the region inshore of 10 km and in the upper 20 m further offshore. Subsurface temperature observations are not coherent with the wind at periods of several days. Close

• 28. [Article] Horizontal transport and the distribution of nutrients in the coastal transition zone off Northern California: effects on primary production, phytoplankton biomass and species composition

  Conductivity-temperature-depth surveys during 1988 encountered strong baroclinic jets that were evident in acoustic Doppler current profiler and hydrographic data. During June and July 1988 a filament ...

  Citation × Citation Citation Abstract Copy Title: Horizontal transport and the distribution of nutrients in the coastal transition zone off Northern California: effects on primary production, phytoplankton biomass and species composition Author: Stanton, Timothy P., Kosro, P. Michael, 1951-, Ramp, Steven R., Rojas de Mendiola, Blanca, Huyer, Adriana, 1945-, Chavez, Francisco P., Barber, Richard T. Conductivity-temperature-depth surveys during 1988 encountered strong baroclinic jets that were evident in acoustic Doppler current profiler and hydrographic data. During June and July 1988 a filament with high surface nitrate, high chlorophyll, abundant populations of neritic centric diatoms, and higher rates of primary production was evident perpendicular to the coast between Point Arena and Point Reyes. However, the high-nutrient and phytoplankton regions were not in the baroclinic jets but were south and inshore of them. Surface water transported offshore by the strong baroclinic jets was found to have relatively low nutrient content, suggesting that the jets themselves do not carry significant levels of coastally upwelled, high-nutrient water to the ocean interior. The low nutrient and salinity content of the jet suggests that the water originated several hundred kilometers upstream. Although the jets themselves do not appear to transport significant levels of nutrients directly from the coastal regime to the oceanic regime, dynamic processes associated with a meandering jet are likely responsible for high surface nutrients found several hundred kilometers offshore. Processes such as upwelling along the southern edge of the seaward jet result in significant enrichment of the coastal transition zone and in large blooms of neritic diatoms. During 1988 the high-nutrient, high-phytoplankton filament was present when the survey sequence began but then decayed after a month. The surface and subsurface nitrate fields were coherent with the dynamic topography field throughout the survey sequence; however, the surface and integrated chlorophyll fields were coherent only through the first two surveys. A decrease in phytoplankton biomass began during the third survey coincident with physical changes which occurred in that time frame: (1) an intensification of the undercurrent and (2) changes in the surface circulation from predominantly offshore to predominantly alongshore. Understanding the processes responsible for the uncoupling between biology and physics is paramount for realistic biological models of this region. Title: Horizontal transport and the distribution of nutrients in the coastal transition zone off Northern California: effects on primary production, phytoplankton biomass and species composition Author: Stanton, Timothy P., Kosro, P. Michael, 1951-, Ramp, Steven R., Rojas de Mendiola, Blanca, Huyer, Adriana, 1945-, Chavez, Francisco P., Barber, Richard T. Conductivity-temperature-depth surveys during 1988 encountered strong baroclinic jets that were evident in acoustic Doppler current profiler and hydrographic data. During June and July 1988 a filament with high surface nitrate, high chlorophyll, abundant populations of neritic centric diatoms, and higher rates of primary production was evident perpendicular to the coast between Point Arena and Point Reyes. However, the high-nutrient and phytoplankton regions were not in the baroclinic jets but were south and inshore of them. Surface water transported offshore by the strong baroclinic jets was found to have relatively low nutrient content, suggesting that the jets themselves do not carry significant levels of coastally upwelled, high-nutrient water to the ocean interior. The low nutrient and salinity content of the jet suggests that the water originated several hundred kilometers upstream. Although the jets themselves do not appear to transport significant levels of nutrients directly from the coastal regime to the oceanic regime, dynamic processes associated with a meandering jet are likely responsible for high surface nutrients found several hundred kilometers offshore. Processes such as upwelling along the southern edge of the seaward jet result in significant enrichment of the coastal transition zone and in large blooms of neritic diatoms. During 1988 the high-nutrient, high-phytoplankton filament was present when the survey sequence began but then decayed after a month. The surface and subsurface nitrate fields were coherent with the dynamic topography field throughout the survey sequence; however, the surface and integrated chlorophyll fields were coherent only through the first two surveys. A decrease in phytoplankton biomass began during the third survey coincident with physical changes which occurred in that time frame: (1) an intensification of the undercurrent and (2) changes in the surface circulation from predominantly offshore to predominantly alongshore. Understanding the processes responsible for the uncoupling between biology and physics is paramount for realistic biological models of this region. Close