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• 1. [Article] Small-Scale Sea Surface Temperature Structure

  Observations of sea surface temperature and wave height were made from a large, manned spar buoy (R/P FLIP) ~100 km off the coast of Baja California. Surface temperature was measured with a radiation thermometer ...

  Citation × Citation Citation Abstract Copy Title: Small-Scale Sea Surface Temperature Structure Author: Paulson, Clayton A., Simpson, James J. Observations of sea surface temperature and wave height were made from a large, manned spar buoy (R/P FLIP) ~100 km off the coast of Baja California. Surface temperature was measured with a radiation thermometer which viewed a disc on the surface 12 cm in diameter. The instrument responded to frequencies up to 3 Hz. Wave height was measured with a resistance gage located close to the field of view of the radiometer. Log-log plots of spectra of sea surface temperature exhibit a plateau between 0.05 and 0.5 Hz, followed by a rapid decrease in energy at frequencies >1 Hz. A coherence of 0.5 between waves and surface temperature occurs at the same frequency as the peak in the wave spectrum. Phase spectra show that warm temperatures associated with the thinning of the surface viscous layer occur systematically upwind of the crests of the dominant gravity waves and downwind of the crests of steeply sloping, shorter period gravity waves. The warm temperatures are hypothesized to be caused by enhanced wind stress upwind from the crests and by surface instability and surface convergence downwind from the crests. The magnitude of the mean temperature difference between the surface and the warmer, well-mixed water below is estimated from the surface temperature record. It is assumed that the warmest surface temperatures observed are associated with thinning of the viscous layer and are representative of the well-mixed water below. The dimensionless constant in a formula due to Saunders (1967), which relates the temperature difference to wind stress and heat flux, is found to be seven. Title: Small-Scale Sea Surface Temperature Structure Author: Paulson, Clayton A., Simpson, James J. Observations of sea surface temperature and wave height were made from a large, manned spar buoy (R/P FLIP) ~100 km off the coast of Baja California. Surface temperature was measured with a radiation thermometer which viewed a disc on the surface 12 cm in diameter. The instrument responded to frequencies up to 3 Hz. Wave height was measured with a resistance gage located close to the field of view of the radiometer. Log-log plots of spectra of sea surface temperature exhibit a plateau between 0.05 and 0.5 Hz, followed by a rapid decrease in energy at frequencies >1 Hz. A coherence of 0.5 between waves and surface temperature occurs at the same frequency as the peak in the wave spectrum. Phase spectra show that warm temperatures associated with the thinning of the surface viscous layer occur systematically upwind of the crests of the dominant gravity waves and downwind of the crests of steeply sloping, shorter period gravity waves. The warm temperatures are hypothesized to be caused by enhanced wind stress upwind from the crests and by surface instability and surface convergence downwind from the crests. The magnitude of the mean temperature difference between the surface and the warmer, well-mixed water below is estimated from the surface temperature record. It is assumed that the warmest surface temperatures observed are associated with thinning of the viscous layer and are representative of the well-mixed water below. The dimensionless constant in a formula due to Saunders (1967), which relates the temperature difference to wind stress and heat flux, is found to be seven. Close

• 2. [Article] Towed thermister chain observations of fronts in the subtropical North Pacific

  Copyrighted by American Geophysical Union.

  Citation × Citation Citation Abstract Copy Title: Towed thermister chain observations of fronts in the subtropical North Pacific Author: Paulson, Clayton A., Samelson, Roger M. Copyrighted by American Geophysical Union. Title: Towed thermister chain observations of fronts in the subtropical North Pacific Author: Paulson, Clayton A., Samelson, Roger M. Copyrighted by American Geophysical Union. Close

• 3. [Article] Horizontal wave number spectra of temperature in the unstably stratified oceanic surface layer

  Horizontal wave number spectra of temperature in the unstably stratified oceanic surface layer were determined from measurements on a bow boom at a depth of 2 m. Spectra were estimated in the wavelength ...

  Citation × Citation Citation Abstract Copy Title: Horizontal wave number spectra of temperature in the unstably stratified oceanic surface layer Author: Paulson, Clayton A., Wijesekera, Hemantha W., Huyer, Adriana, 1945- Horizontal wave number spectra of temperature in the unstably stratified oceanic surface layer were determined from measurements on a bow boom at a depth of 2 m. Spectra were estimated in the wavelength band from 2 m to 2 km, normalized in accordance with Monin-Obukhov similarity theory, and averaged in groups with similar stability parameter and fractional mixed layer depth. The shapes of the wave number-weighted oceanic spectra agree qualitatively with observed and modeled atmospheric spectra, including the wavelength of the peaks and the variation of peak wave number with stability. However, the peak spectral levels disagree by as much as a factor of two and the variation of spectral level with stability is in the opposite sense for the oceanic and atmospheric spectra. The wave number of the peak in the near neutral oceanic spectrum is similar to the wave number of the peak in the longitudinal velocity spectrum observed in the atmospheric surface layer, which is consistent with temperature acting as a passive tracer in near neutral conditions. The wave number of the peak in the free convection oceanic spectrum is similar to the wave number of the peak in the spectrum of vertical velocity observed in the atmospheric surface layer during free convection, which reflects the dynamical role played by temperature in a freely convecting boundary layer. The difference between oceanic and modeled near-neutral spectral levels at a wavelength of 2 m suggests that dissipation could be enhanced (u p to a factor of three) by surface wave breaking. Title: Horizontal wave number spectra of temperature in the unstably stratified oceanic surface layer Author: Paulson, Clayton A., Wijesekera, Hemantha W., Huyer, Adriana, 1945- Horizontal wave number spectra of temperature in the unstably stratified oceanic surface layer were determined from measurements on a bow boom at a depth of 2 m. Spectra were estimated in the wavelength band from 2 m to 2 km, normalized in accordance with Monin-Obukhov similarity theory, and averaged in groups with similar stability parameter and fractional mixed layer depth. The shapes of the wave number-weighted oceanic spectra agree qualitatively with observed and modeled atmospheric spectra, including the wavelength of the peaks and the variation of peak wave number with stability. However, the peak spectral levels disagree by as much as a factor of two and the variation of spectral level with stability is in the opposite sense for the oceanic and atmospheric spectra. The wave number of the peak in the near neutral oceanic spectrum is similar to the wave number of the peak in the longitudinal velocity spectrum observed in the atmospheric surface layer, which is consistent with temperature acting as a passive tracer in near neutral conditions. The wave number of the peak in the free convection oceanic spectrum is similar to the wave number of the peak in the spectrum of vertical velocity observed in the atmospheric surface layer during free convection, which reflects the dynamical role played by temperature in a freely convecting boundary layer. The difference between oceanic and modeled near-neutral spectral levels at a wavelength of 2 m suggests that dissipation could be enhanced (u p to a factor of three) by surface wave breaking. Close

• 4. [Article] Towed thermistor chain observations in FRONTS-80

  Citation × Citation Citation Abstract Copy Title: Towed thermistor chain observations in FRONTS-80 Author: Paulson, Clayton A., Oregon State University. School of Oceanography Title: Towed thermistor chain observations in FRONTS-80 Author: Paulson, Clayton A., Oregon State University. School of Oceanography Close

• 5. [Article] Towed thermistor chain observations in JASIN

  Citation × Citation Citation Abstract Copy Title: Towed thermistor chain observations in JASIN Author: Paulson, Clayton A., Baumann, R. J., Wagner, J., Oregon State University. School of Oceanography Title: Towed thermistor chain observations in JASIN Author: Paulson, Clayton A., Baumann, R. J., Wagner, J., Oregon State University. School of Oceanography Close

• 6. [Article] Towed thermistor chain observations across the Gulf Stream

  Citation × Citation Citation Abstract Copy Title: Towed thermistor chain observations across the Gulf Stream Author: Levine, Murray D., Paulson, Clayton A., deWitt, L. M., Wagner, J. D., Baumann, R. J. Title: Towed thermistor chain observations across the Gulf Stream Author: Levine, Murray D., Paulson, Clayton A., deWitt, L. M., Wagner, J. D., Baumann, R. J. Close

• 7. [Article] FRONTS 80 : preliminary results from an investigation of the wintertime North Pacific subtropical front

  Citation × Citation Citation Abstract Copy Title: FRONTS 80 : preliminary results from an investigation of the wintertime North Pacific subtropical front Author: Paulson, Clayton A., Niiler, Pearn P., Oregon State University. School of Oceanography Title: FRONTS 80 : preliminary results from an investigation of the wintertime North Pacific subtropical front Author: Paulson, Clayton A., Niiler, Pearn P., Oregon State University. School of Oceanography Close

• 8. [Article] Mixed layer observations during the NORPAX POLE experiment : a data report

  Citation × Citation Citation Abstract Copy Title: Mixed layer observations during the NORPAX POLE experiment : a data report Author: Paulson, Clayton A., Simpson, James J. Title: Mixed layer observations during the NORPAX POLE experiment : a data report Author: Paulson, Clayton A., Simpson, James J. Close

• 9. [Article] Structure and dynamics of a coastal filament

  Copyrighted by American Geophysical Union.

  Citation × Citation Citation Abstract Copy Title: Structure and dynamics of a coastal filament Author: Dewey, Richard K., Paulson, Clayton A., Caldwell, Douglas R., Pierce, Stephen D., Moum, James N. Copyrighted by American Geophysical Union. Title: Structure and dynamics of a coastal filament Author: Dewey, Richard K., Paulson, Clayton A., Caldwell, Douglas R., Pierce, Stephen D., Moum, James N. Copyrighted by American Geophysical Union. Close

• 10. [Article] Simulation of turbulent exchange processes in summertime leads

  Ice-ocean heat exchange in polar leads was examined using a large-eddy simulation model coupled to a slab ice model. Simulations were performed using an idealized square domain for a range of lead sizes, ...

  Citation × Citation Citation Abstract Copy Title: Simulation of turbulent exchange processes in summertime leads Author: Skyllingstad, Eric D., Paulson, Clayton A., Pegau, W. Scott Ice-ocean heat exchange in polar leads was examined using a large-eddy simulation model coupled to a slab ice model. Simulations were performed using an idealized square domain for a range of lead sizes, surface wind stress (0.05–0.1 N/m²), and lead temperature/salinity profiles. Particular emphasis was placed on understanding the role of fresh water in leads and how stratification controls the heat budget and ice edge melting rate. With uniform initial conditions we found that solar heating was not strong enough to develop lead freshening via ice edge melting; even weak winds (0.02 N/m²) generated circulations that maintained a well-mixed lead. In the weak wind case, adding a fresh water flux representative of surface melt runoff provided enough additional stratification so that the lead water became isolated from the rest of the simulated ocean boundary layer. However, stronger winds (0.1 N/m²) prevented the fresh water layer from forming. Experiments initialized with temperature/salinity profiles similar to observed cases (fresh water layer capping the lead) demonstrated that lateral melting rates increase with expanding lead size, agreeing with simple heat balance calculations for a square lead without vertical mixing. However, with stronger winds, lateral melting rates decreased because of greater turbulent mixing of cold water from beneath the fresh layer. Inspection of the lead circulation indicated that the strongest melting occurred where the ice edge currents were the largest. Overall, melting fluxes for a 24 m² lead ranged from 200 to 400 W m², depending on the wind speed. Without the fresh layer, fluxes ranged from 50 to 60 W m², suggesting that fresh water stratification can have a dominate role in controlling ice edge melting. Title: Simulation of turbulent exchange processes in summertime leads Author: Skyllingstad, Eric D., Paulson, Clayton A., Pegau, W. Scott Ice-ocean heat exchange in polar leads was examined using a large-eddy simulation model coupled to a slab ice model. Simulations were performed using an idealized square domain for a range of lead sizes, surface wind stress (0.05–0.1 N/m²), and lead temperature/salinity profiles. Particular emphasis was placed on understanding the role of fresh water in leads and how stratification controls the heat budget and ice edge melting rate. With uniform initial conditions we found that solar heating was not strong enough to develop lead freshening via ice edge melting; even weak winds (0.02 N/m²) generated circulations that maintained a well-mixed lead. In the weak wind case, adding a fresh water flux representative of surface melt runoff provided enough additional stratification so that the lead water became isolated from the rest of the simulated ocean boundary layer. However, stronger winds (0.1 N/m²) prevented the fresh water layer from forming. Experiments initialized with temperature/salinity profiles similar to observed cases (fresh water layer capping the lead) demonstrated that lateral melting rates increase with expanding lead size, agreeing with simple heat balance calculations for a square lead without vertical mixing. However, with stronger winds, lateral melting rates decreased because of greater turbulent mixing of cold water from beneath the fresh layer. Inspection of the lead circulation indicated that the strongest melting occurred where the ice edge currents were the largest. Overall, melting fluxes for a 24 m² lead ranged from 200 to 400 W m², depending on the wind speed. Without the fresh layer, fluxes ranged from 50 to 60 W m², suggesting that fresh water stratification can have a dominate role in controlling ice edge melting. Close