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Showing papers in "Journal of Physical Oceanography in 1972"


Journal ArticleDOI
TL;DR: In this paper, observations are available to show that, early in the hurricane season, there are varying initial conditions in the Gulf of Mexico which could lead to significantly different total heat exchanges.
Abstract: It has been demonstrated that a large input of energy from the ocean is necessary to establish and maintain hurricane force winds over the sea. However, there has been no suitable data which could serve as a basis for calculating this input. Now, observations are available to show that, early in the hurricane season, there are varying initial conditions in the Gulf of Mexico which could lead to significantly different total heat exchanges. The sea can provide some seven days of energy flow into a hurricane at some times and at some locations, but less than one day in others depending upon the amount of heat initially available in the Gulf waters. In the four summers represented by the data, a quantity defined as hurricane heat potential was found to vary from a low of 700 cal cm−2 column north of Yucatan to a high of 31,600 in the central east Gulf. Synoptic data on hurricane heat potential, if made regularly available to forecasters, might serve as a basis for improved forecasts of changes in In...

295 citations



Journal ArticleDOI
TL;DR: In this article, a wind-driven model of coastal upwelling induced into a stratified, rotating ocean is solved numerically and a multilevel model is derived, but only solutions for a two-layer model are discussed.
Abstract: A wind-driven model of coastal upwelling induced into a stratified, rotating ocean is solved numerically. The circulation is on an f plane and longshore variations are neglected. A multilevel model is derived, but only solutions for a two-layer model are discussed. A longshore baroclinic surface jet is discovered. The time-dependent geostrophic jet is dynamically explained by conservation of potential vorticity. The existence of the jet depends critically on stratification and non-zero wind stress at the coast. Coastal upwelling is confined to within 30 km of the shore. The model exhibits no deep countercurrent during active coastal upwelling. A time scale of the order of 10 days or longer is required for a pycnocline at 50 m depth to penetrate the surface. Solutions for a wide (>300 km) coastal shelf, an irregular shallow shelf, and a continental slope region are illustrated. A secondary upwelling region is found offshore at sharp breaks in the shelf topography. In all cases, the offshore flow i...

121 citations


Journal ArticleDOI
TL;DR: In this article, the bottom boundary layer of the Florida Current at a representative site in the Straits of Florida was studied and the objectives of the experiment were 1) to study the topology of the current and 2) to evaluate the performance of the experimental results.
Abstract: This is a report of an experiment designed to study the bottom boundary layer of the Florida Current at a representative site in the Straits of Florida. The objectives of the experiment were 1) to ...

110 citations


Journal ArticleDOI
TL;DR: In this paper, the influence of wind on phase speeds of waves was investigated by solving the first order perturbation problem of the coupled shear flows in air and water, and a logarithmic drift profile was proposed.
Abstract: Measurements of drift were made in a wind and wave facility at different elevations below the mean water level. The drift profiles were obtained for reference wind speeds, Ur = 3.1, 5.7 and 9.6 m/sec. The measurement technique involved tracing the movement of small paper discs which were soaked in water to become neutrally buoyant at the elevation of release. A logarithmic drift profile is proposed. The water shear velocity, U*w, predicts a surface stress, TS = pw U*S, in agreement with that obtained from the wind shear velocity, Ts = Pa U*li where pa and pw refer to air and water densities, respectively. The influence of wind on phase speeds of waves was investigated by solving the first order perturbation problem of the coupled shear flows in air and water. The air velocity profile was described by a logarithmic distribution and the drift profile was described by the proposed drift profile. Adequate agreement is found between the calculated and measured phase speed using Doppler radar in the wave number range 1.9 - 10 cm-1. In the wave number range 0.05 - 0.5 cm-1, measurements of phase speeds were obtained by using two wave gages. The waves were mechanically generated without wind and the wave gages were spaced to obtain coherent signals. The wind was then allowed to blow over the waves and the distance between wave gages was increased to maintain coherence. The wave length and frequency were obtained from the distance between the gages and from the generator frequency, respectively. The measured phase speeds were found to increase with wind speed consistent with theoretical computations.

104 citations


Journal ArticleDOI
TL;DR: In this paper, a method called resonance iteration was proposed to calculate the period and configuration of free oscillations in a way that provides for the full two-dimensionalality of the problem, and thus avoids limitations such as are inherent in the traditional channel approximation.
Abstract: A method is designed to calculate normal modes of natural basins. The purpose is to determine the period and configuration of free oscillations in a way that provides for the full two-dimensionality of the problem, and thus avoids limitations such as are inherent in the traditional channel approximation. The method—called resonance iteration—is amenable to detailed numerical analysis. As a test, the lowest positive and negative modes in a rotating square basin of uniform depth are calculated for a range of rotation speeds, with results that agree well with existing evaluations of this case. Similar agreement was found in an application to Lake Erie, a basin that conforms to the channel approximation. The method was then applied to two basins where it was expected to give results differing from those obtained by earlier methods: Lake Superior and the Gulf of Mexico. The fundamental gravitational mode of Lake Superior was found to have a period of 7.84 hr, which is 9% greater than the value known f...

100 citations


Journal ArticleDOI
TL;DR: In this paper, a time series of surface winds and sea surface temperatures at Canton Island, covering the period 1962-67, is interpreted to show that the major changes in the temperature of the large central and eastern equatorial Pacific area are caused by varying strength of the easterly winds and inherent variation in upwelling.
Abstract: Time series of surface winds and sea surface temperatures at Canton Island, covering the period 1962–67, are interpreted to show that the major changes in the temperature of the large central and eastern equatorial Pacific area are caused by the varying strength of the easterly winds and inherent variation in upwelling. The feedback effects of the ocean temperature variations upon the atmosphere are illustrated by a comparison of the average November 1964 sounding with that of November 1965. In the cold ocean case (1964) the atmosphere has a pronounced stable layer between 900 and 800 mb, preventing convection and rainfall, and in the warm ocean case (1965) the heat supply from the ocean eliminates the atmospheric stability and activates heavy rainfall. The resulting vertical thermal expansion of the tropical troposphere from 1964 to 1965 is demonstrated by 200-mb topographic maps showing the emergence of two new anticyclonic centers symmetrically straddling the equator at the longitude of the ma...

90 citations


Journal ArticleDOI
TL;DR: In this paper, a time-dependent, finite-amplitude, theoretical analysis of this instability has been made and expressions for the preferred horizontal spacing and velocities of the resulting convection currents have been derived for conditions that may be typ...
Abstract: Due to the nonlinear equation of state of sea water it is possible for the mixture of two Parcels of sea water with the same density but different temperatures and salinities to have a density greater than that of the constituent parcels. This phenomenon is sometimes called cabbeling. In the deep parts of the Weddell Sea the surface water is usually colder and less saline than the underlying deep water. In winter the salinity of the surface water can increase due to sea ice formation, and then mixtures of surface water and deep water may become denser than the underlying deep water. An instability can develop which may transport the heavier mixed water through the deep water and contribute to the formation of Antarctic Bottom Water. A time-dependent, finite-amplitude, theoretical analysis of this instability has been made. Assuming turbulent mixing, expressions for the preferred horizontal spacing and velocities of the resulting convection currents have been derived for conditions that may be typ...

87 citations


Journal ArticleDOI
TL;DR: In this paper, the Kitaigorodskii-Pierson-Moskowitz frequency spectrum is used as the basic spectral form for zero current condition and modified spectral functions in both wavenumber and frequency spaces under the influence of current are found by using energy conservation and kinematic wave conservation laws.
Abstract: Interactions between steady non-uniform currents and gravity waves are generalized to include the case of a random gravity wave field. The Kitaigorodskii-Pierson-Moskowitz frequency spectrum is used as the basic spectral form for zero current condition. Modified spectral functions in both wavenumber and frequency spaces under the influence of current are found by using energy conservation and kinematic wave conservation laws. The relative importance of the current-wave interaction was measured by the nondimensional parameter U/C0, with U as the current speed and C0 the phase speed of a wave under no current. As a result of the current-wave interaction, the magnitude and the location of the energy peak in the spectrum is altered. Since the phase speed of gravity waves is a monotonically decreasing function of wavenumber and frequency, the influence of current will be predominant at the higher wavenumber range. Furthermore, the contribution from the higher wavenumber range dominates the surface slo...

85 citations


Journal ArticleDOI
TL;DR: In this paper, the thermohaline structure, vertical stability and baroclinic flow between the Gulf of California entrance and the Revilla Gigedo islands are investigated by means of closely spaced salinity and temperature depth profiles (STD's).
Abstract: The thermohaline structure, vertical stability and baroclinic flow between the Gulf of California entrance and the Revilla Gigedo islands are investigated by means of closely spaced salinity and temperature depth profiles (STD's). The outstanding feature of the upper ocean is the 10–30 m thick layer of high stability centered at about 50 m. This layer separates the tropical surface water from the thin shallow salinity minimum below, which is most pronounced between 80 and 130 m. The outstanding feature of the deep water is the marked increase in abyssal temperatures east of Isla Socorro, apparently due to heat flow. Baroclinic flow in the Revilla Gigedo islands region is characterized by high-speed flow near capes and islands. Outflow from the Gulf of California takes place in a narrow high velocity core near its western side. The width of the high-speed core is of the order of 30 km and speeds >30 cm sec−1 occur down to 700 m. The high-speed flow is accomplished by a break in the high stability ...

83 citations


Journal ArticleDOI
TL;DR: In this article, the upward and downward flux at various levels in the atmosphere and ocean is calculated by a Monte Carlo method which includes all orders of multiple scattering, including Rayleigh scattering by the molecules and Mie scattering by aerosols as well as molecular and aerosol absorption.
Abstract: The upward and downward flux at various levels in the atmosphere and ocean is calculated by a Monte Carlo method which includes all orders of multiple scattering. A realistic model of the atmosphere-ocean system is used. In the atmosphere, both Rayleigh scattering by the molecules and Mie scattering by the aerosols as well as molecular and aerosol absorption are included in the model. Similarly, in the ocean, both Rayleigh scattering by the water molecules and Mie scattering by the hydrosols as well as absorption by the water molecules and hydrosols are considered. Separate single-scattering functions are calculated from the Mie theory for the aerosols and the hydrosols with an appropriate and different size distribution in each case. The scattering angles are determined from the appropriate scattering function including the strong forward-scattering peak when there is aerosol or hydrosol scattering. Both the reflected and refracted rays, as well as the rays that undergo total internal reflection...

Journal ArticleDOI
TL;DR: In this paper, a series of numerical experiments are carried out to simulate the three-dimensional circulation in the North Atlantic Ocean and to examine the dynamics therein, and the results of the basic experiment are compared with observations.
Abstract: A series of numerical experiments are carried out to simulate the three-dimensional circulation in the North Atlantic Ocean and to examine the dynamics therein. The calculations are partly diagnostic in that the density field is not predicted but is given from observations. The main predicted quantities are the velocity and pressure fields. The results of the basic experiment are compared with observations. The surface currents are quite similar to observations based upon ship drift data, and the surface pressure field is nearly identical to the height of the free surface constructed from a level-of-no-motion hypothesis. The deep pressure variations are nowhere flat or level, however, and the predicted deep currents are quite complex. They are, in fact, strongly controlled by bottom topography and tend to follow f/H contours, where f is the Coriolis parameter and H the depth. The Gulf Stream transport is quite large, reaching a maximum value of 81×106 m3 sec−1, despite the lack of important inert...

Journal ArticleDOI
TL;DR: An approximation to the UNESCO equation of state for sea water is obtained in the form of a polynomial that is cubic in potential temperature, quadratic in pressure, and linear in salinity as mentioned in this paper.
Abstract: An approximation to the UNESCO equation of state for sea water is obtained in the form of a polynomial that is cubic in potential temperature, quadratic in pressure, and linear in salinity. The polynomial represents a reasonable compromise between accuracy and computational economy; it also allows potential temperature to be obtained analytically from given values of density, salinity and pressure.

Journal ArticleDOI
TL;DR: In this paper, the authors used a homogeneous model of the World Ocean with 9 levels in the vertical and a horizontal resolution of 2°×2° in latitude and longitude.
Abstract: Calculations are carried out for a homogeneous model of the World Ocean. Solutions for the large-scale, wind-driven circulation are obtained by numerical integration with respect to time of a numerical model. The model includes 9 levels in the vertical and has a horizontal resolution of 2°×2° in latitude and longitude. Subgrid-scale motions are included implicitly through the eddy viscosity hypothesis. The level of viscosity is adjusted so that only scales of motion large enough to be resolved by the numerical model will have appreciable amplitude. Compared with available observations, the model with uniform depth tends to underpredict the strength of the transport in the Northern Hemisphere boundary currents, but overpredict the strength of the Antarctic Circumpolar Current and the East Australian Current. When bottom topography is taken into account, the Northern Hemisphere transport patterns are not greatly altered, but transport of the Antarctic Circumpolar Current and the East Australian Cur...

Journal ArticleDOI
TL;DR: In this article, the response of a simple Great Lake model to wind stress is studied theoretically, where the model is of constant depth and of circular shape, continuously stratified with a thermocline region of linear density distribution.
Abstract: The response of a simple Great Lake model to wind stress is studied theoretically. The model is of constant depth and of circular shape, continuously stratified with a thermocline region of linear density distribution. The excitation of natural modes of oscillation is calculated for a suddenly imposed uniform wind stress and for one acting for a finite period. The results show that strong Kelvin-type (shore-bound) waves are generated in the first few baroclinic modes, which give rise to “coastal jets” of a width of order 5 km and less, the combination of several baroclinic modes resulting in a complex structure for these jets. In the central portions of the lake model the response consists of Poincare-type waves of near-inertial frequency. The qualitative features of the theoretical results agree quite well with observational evidence from the Great Lakes.

Journal ArticleDOI
TL;DR: The net loss of heat by the Mediterranean Sea was determined for February 1969 while oceanographers observed the cooling and sinking of the water south of France as mentioned in this paper, and the heat loss during the four preceding months was found to be sufficient to produce the unstable stratification necessary for the sinking of water.
Abstract: The net loss of heat by the Mediterranean Sea was determined for February 1969 while oceanographers observed the cooling and sinking of the water south of France. The heat loss during the four preceding months was found to be sufficient to produce the unstable stratification necessary for the sinking of the water. The mistral wind removed most of the heat through evaporation and sensible heat flux. On days when the mistral was blowing 1200 cal cm−2 day−1 of heat and 1.5 cm day−1 of water were removed from the sea. Throughout the winter season an average of 400 cal cm−2 day−1 was lost by the sea through sensible and latent heat fluxes. About half of the solar radiation absorbed by the water in the winter was lost through infrared radiation. Monthly heat exchanges are computed for an area south of France which show the dominant roles of latent heat exchange and solar radiation absorption in determining the temperature cycle and circulation of Mediterranean water. The flow patterns, turbulence and e...

Journal ArticleDOI
TL;DR: In this article, the results of observations collected during the "spring" period (May to early June) which showed a current regime different in character from that observed during summer or fall were presented.
Abstract: Originally prompted by a desire to search for theoretically predicted “coastal jets,” an extensive series of observations on currents in the coastal zone near Oshawa, in Lake Ontario, were carried out during 1969 and 1970. The observation technique consisted of anchoring marker flag stations at increasing distances from the shore, forming a “coastal chain” more or less perpendicular to the shore, then collecting current and temperature observations from a small boat by hand-held instruments at a number of depths at each station. During the 1970 season a set of four fixed current meters was also used, providing a temporal history of the currents. This paper presents the results of observations collected during the “spring” period (May to early June) which showed a current regime different in character from that observed during summer or fall. A near-shore band (∼7 km wide) becomes a unique kind of boundary layer in which mid-lake motions adjust to the presence of the shores. During the spring sign...

Journal ArticleDOI
TL;DR: In this paper, the Alaskan Stream boundary current south of the uniformly curving coastline formed by the Alaska peninsula-Aleutian island chain is examined analytically via steady, barotropic frictional theory.
Abstract: The Alaskan Stream boundary current south of the uniformly curving coastline formed by the Alaskan peninsula-Aleutian Island chain is examined analytically via steady, barotropic frictional theory. It is shown that, as a result of the changing zonal orientation of this boundary, there is an alteration in the characteristic vorticity balance in the current as it progresses westward from the Gulf of Alaska. Where the curving coastline becomes approximately zonal, this vorticity distribution is such that, unless the clockwise vorticity generated at the coast by the no-slip condition is balanced by a vorticity source external to the current, instabilities and separation of the Alaskan Stream from the coast will occur.

Journal ArticleDOI
TL;DR: One hundred fortyone simultaneous wind speed, temperature and humidity profiles measured during the Barbados Oceanographic and Meteorological Experiment (BOMEX) are analyzed in this paper, where the observations were from heights 2-11 m above MSL and were made from the R/V Flip, a research vessel specially designed to be stable at sea.
Abstract: One hundred forty-one simultaneous wind speed, temperature and humidity profiles measured during the Barbados Oceanographic and Meteorological Experiment (BOMEX) are analyzed. The observations were from heights 2–11 m above MSL and were made from the R/V Flip, a research vessel specially designed to be stable at sea. The wind measurements are corrected for the interference of Flip's hull with the air flow. Evaporation estimates from the profiles are in fair agreement with simultaneous estimates by the eddy-correlation method. However, the heat fluxes estimated by the two methods are in poor agreement. There appear to be diurnal variations in air temperature, sea surface temperature and stress. The flux of latent heat is large, averaging 17 mW cm−2, while the flux of sensible heat is always upward and ∼1 mW cm−2.

Journal ArticleDOI
TL;DR: In this article, the authors examined the two-dimensional convective motion of a nonrotating incompressible Boussinesq fluid heated non-uniformly from below.
Abstract: This paper examines the two-dimensional convective motion of a nonrotating incompressible Boussinesq fluid heated non-uniformly from below. The fluid container is rectangular; the side and top boundaries are insulating and rigid. A linear temperature field is maintained along the bottom boundary. Using the DuFort-Frankel scheme for diffusion and the Arakawa scheme for advection, the governing vorticity and temperature equations are integrated numerically for two cases, the first having a stress-free bottom boundary and the second having a constant stress along the bottom boundary. In the first case, a single convective cell develops; an intense buoyant jet of fluid rises from the warmer section of the bottom while there is a more uniform sinking motion over the cooler section of the bottom. The cell asymmetry, the circulation, and the convective heat transfer increase markedly with increasing Rayleigh number (based here on fluid properties, cell height, and the horizontal temperature difference a...

Journal ArticleDOI
TL;DR: In this article, field observations on coastal currents near Oshawa on the north shore of Lake Ontario during summer and fall are described, showing that the kinetic energy level of water movements increases considerably from spring to summer and again from summer to fall.
Abstract: Field observations on coastal currents near Oshawa on the north shore of Lake Ontario during summer and fall are described. The technique of observations (flag-station chain) has been given in Part I, together with a description of the dynamic regime during the spring period. Observations during summer and fall show that the kinetic energy level of water movements increases considerably from spring to summer and again from summer to fall. Much as in the spring, a nearshore band (some 10 km wide) becomes a unique kind of “boundary layer” in which mid-lake motions adjust to the presence of the shares. In this shore zone, currents are shore-parallel and relatively persistent. During summer and fall, mid-lake motions are wave-like, consisting mainly of near-inertial oscillations. Within the shore zone, the current-like motions are associated with thermocline displacements, upward if the current flows to the east, downward if it flows to the west, so that the pressure gradients caused by the non-unifo...

Journal ArticleDOI
TL;DR: In this article, a theoretical analysis of haline convection induced by the freezing of sea water is made for a turbulent ocean, and the nonlinear equations for two-dimensional flow are solved using the mean field approximation and expanding the variables in Fourier series.
Abstract: A theoretical analysis of haline convection induced by the freezing of sea water is made for a turbulent ocean. The nonlinear equations for two-dimensional flow are solved using the mean field approximation and expanding the variables in Fourier series. It is found that, when the depth of the mixed layer is sufficiently large, the convective process is independent of depth. Expressions for the horizontal spacing of convection cells, maximum vertical velocity, and time required for manifest convection to develop are derived for a range of Schmidt numbers appropriate for the ocean. The analysis is applied to conditions that may be typical of freshly frozen polynyas or leads in the Weddell Sea, and it is concluded that haline convection is probably an effective process as a precursor to Antarctic Bottom Water formation.

Journal ArticleDOI
TL;DR: In this paper, a steady-state model of Lake Vanda is considered which determines that heat flux through each double-diffusive interface which is necessary to maintain the lake in a steady state.
Abstract: Recently, Fedorov has attempted to interpret some temperature and salinity profiles in the northeast Atlantic, as reported by Zenk, in terms of the results of laboratory experiments in double-diffusive convection. We argue here that the laboratory experiments do not adequately cover all the oceanographic phenomena contained in these records and that Fedorov's interpretation is inappropriate. Before laboratory results can he used at all in interpreting oceanographic data, however, confirmation that the results of small-scale experiments can be transferred quantitatively to large-scale motions is needed. Such a confirmation is attempted here using the observed profiles in Lake Vanda. A steady-state model of Lake Vanda is considered which determines that heat flux through each double-diffusive interface which is necessary to maintain the lake in a steady state. Using an empirical formula connecting the heat flux and the temperature jump across an interface, we calculate a temperature profile for tha...

Journal ArticleDOI
TL;DR: In this article, the seasonal variation of large-scale upwelling off northwestern Mexico is investigated by means of the divergence of the Ekman transport, computed for a 1° latitude-longitude grid.
Abstract: The seasonal variation of large-scale upwelling off northwestern Mexico is investigated by means of the divergence of the Ekman transport, computed for a 1° latitude-longitude grid. It is found, by using such a close grid, that the vertical velocity is resolved in sufficient detail to bring out many important features of upwelling that agree favorably with the temperature distribution. The limitations of the method are discussed.

Journal ArticleDOI
TL;DR: The Juan de Fuca submarine canyon has depths exceeding 200 m extending completely across the continental shelf as mentioned in this paper, and observations of currents in the canyon during winter 1970 showed relatively large currents and large excursions both in- and out-canyon.
Abstract: Juan de Fuca submarine canyon has depths exceeding 200 m extending completely across the continental shelf. Observations of currents in the canyon during winter 1970 showed relatively large currents and large excursions both in- and out-canyon. Three major flow reversals appear related to major wind reversals as a compensating current to an Ekman surface regime. A fourth wind reversal, not accompanied by flow reversal, indicates that along-canyon density gradients are also important.

Journal ArticleDOI
TL;DR: In the case of the Norwegian Sea, Worthington as mentioned in this paper suggested a mechanism for maintaining the negative heat flux, whereby warm surface water is advected northward to replace the dense, deep water formed within that sea by the cooling action of the atmosphere.
Abstract: Regions of large (>60 kcal cm−2 year−1) net annual heat flux from the oceans to the atmosphere are found only on the western sides of Northern Hemisphere oceans and in the Norwegian Sea, according to Budyko. It has been assumed that these negative heat fluxes are the result of the transport of warm water to middle and high latitudes by major ocean currents, specifically the Gulf Stream, the North Atlantic Current and the Kuroshio. In the case of the Norwegian Sea, Worthington suggested a mechanism for maintaining the negative heat flux, whereby warm surface water is advected northward to replace the dense, deep water formed within that sea by the cooling action of the atmosphere. The deep water mass so formed overflows the sills of the Norwegian Sea and moves southward into the depths of the Atlantic. It is postulated 1) that this mechanism maintains the negative heat fluxes found at mid-latitudes on the northwestern sides of the oceans, and 2) that water masses are also formed at these latitudes...

Journal ArticleDOI
TL;DR: In this article, a servomechanism of the ocean and the atmosphere is defined, the natural time scales of which are determined by a mathematical development wherein the vertically integrated vorti...
Abstract: During the autumn and winter seasons, large amounts of heat are given up to the atmosphere at the subarctic frontal zone off the east coast of Asia. According to Fisher, the Laplacian of this heat flux (∇2Q) is related to increases in the intensity of the relative vorticity in the westerly wind regime. This increase is related to a similar increase in strength of the wind stress curl, which thereby increases the Sverdrup transport of the subarctic and subtropical gyres. The increase in transport in turn intensifies ∇2Q at the subarctic frontal zone via geostrophic adjustment. This coupling of atmospheric relative vorticity, Sverdrup transport, and ∇2Q results in the intensification of the relative vorticity of both fluid media that can be checked only by an instability in either one or the other media. This mutual interaction of the ocean and atmosphere is termed a servomechanism, the natural time scales of which are determined by a mathematical development wherein the vertically integrated vorti...

Journal ArticleDOI
TL;DR: A detailed pattern of surface currents has been derived from drift bottle returns and releases observed during a 10-year study from 1961-71 as mentioned in this paper, where a total of 21,285 drift bottles were released within 165 n mi of the Oregon coast, of which 2937 bottles were eventually recovered.
Abstract: It is generally known that surface currents off Oregon flow equatorward in summer when winds are from the northwest and poleward in the winter when winds are from the south. A detailed pattern of surface currents has been derived from drift bottle returns and releases observed during a 10-year study from 1961–71. A total of 21,285 drift bottles were released within 165 n mi of the Oregon coast, of which 2937 bottles were eventually recovered. The annual cycle of surface currents indicated from these returns was as follows: Northward–October through February Southward–May through August Variable–March, April and September The Davidson current or (northward) winter current was considered to be any northward prevalence of surface flow. The Davidson current commonly reached 48–50N. Every year of the study, some surface blow off Oregon reached as far north as southeast Alaska to about 55N. Although drift bottle observations often indicate northward surface flow all the way to at least the edge of the ...

Journal ArticleDOI
TL;DR: In this paper, the authors used the Bissett Berman salinity-temperature-depth multisensor unit and the Eppley pyranometer to estimate the diurnal variation in temperature at all depths in the oceanic mixed layer at five fixed-ship positions.
Abstract: The regularity and completeness of temperature soundings for a 12-day period during the 1969 Barbados Oceanographic and Meteorological Experiment (BOMEX) has permitted an analysis of the diurnal variation in temperature at all depths in the oceanic mixed layer at five fixed-ship positions The growth and decline of the diurnal thermocline is pronounced and is well documented for all five ship positions The primary instruments used were the Bissett Berman salinity-temperature-depth multisensor unit and the Eppley pyranometer The oceanic heat storage term was combined in an energy budget equation with incident radiation measurements and estimates for advection and back radiation, so that estimates of the diurnal amplitude and phase of the evaporative and sensible heat transfer could be obtained A mean evaporation rate of about 58 mm day−1 was determined The highest evaporation rates were calculated for a 6-hr period centered on the time of local sunset, and the lowest rates were found to occur

Journal ArticleDOI
TL;DR: In this paper, the reflection and nonlinear interaction between the first and second harmonics of a two-dimensional Boussinesq wavetrain was investigated and the effects of topography were included, the depth departing from a constant in a finite region.
Abstract: We investigate the reflection and nonlinear interaction between the first and second harmonics of a two-dimensional Boussinesq wavetrain. Effects of topography are included, the depth departing from a constant in a finite region. It is found that topography can speed up or retard energy transfer between first and second harmonics. The reflection coefficient in the present context is significantly different from the one obtained by using linear theory. This is partly due to partitioning of energy between harmonics.