CTD observations on the North Brazil shelf during a multidisciplinary Amazon Shelf Sediment Study, AMASSEDS, August 1989

CTD and acoustic Doppler current profiler (ADCP) observations were made on the North Brazil shelf adjacent to the mouth of the Amazon River during R/V Iselin cruise I8909 August 3-14, 1989 as part of A Multidisciplinary Amazon Shelf SEDiment Study (AMASSEDS). These observations were obtained during a large-scale survey in support of geological and geochemical sampling, an anchored time series station consisting of 26 hourly CTD casts, and one transect which was repeated off the mouth of the Amazon River. The maximum sampling depth at each station was within two meters of the bottom. The primary objectives of the AMASSEDS hydrographic measurement program were to (a) observe and characterize the temperature, salinity, density, oxygen, fluorescence and light transmission fields and their spatial variability on the north Brazilian shelf directly influenced by the Amazon River discharge, (b) resolve the seaward extent and vertical structure of the surface plume of low salinity Amazon River water during different stages of river discharge, (c) describe the spatial structure of the turbidity and associated suspended sediment distributions across the shelf, (d) characterize the properties of the Amazon shelf water beneath the surface plume and their seasonal variability, and (e) describe the landward penetration of the North Brazil Current (NBC) with respect to water properties and shelf currents. This report represents a summary in graphic and tabular form of the hydrographic observations made during the first AMASSEDS cruise (I8909) on the R/V Iselin.Funding was provided by the National Science Foundation through Grant Number OCE 88-1291

CTD observations off northern California during the Shelf Mixed Layer Experiment, SMILE, May 1989

CTD observations were made off the northern California coast during R/V Wecoma cruise W8905 May 5-14, 1989 as part of the Shelf Mixed Layer Experiment (SMILE). The surveys consisted of two sampling plans - a large-scale grid of four cross-shelf transects extending to both sides of Point Arena and Point Reyes, and a small-scale grid of six cross-shelf transects located near the central SMILE mooring site. All of the cross-shelf transects extended beyond the shelf break and the maximum sampling depth at each station was near-bottom or 1500 m. The average along-shelf separation between cross-shelf transects was about 15 km for the small-scale surveys and 50 km for the large-scale grid. The primary objectives of the hydrographic measurement program were to observe and characterize the temperature, salinity, density, and light transmission fields and their temporal and spatial variability in the surface boundary layer along the continental shelf and slope near the SMILE moored array, and to acquire estimates of the cross- and along-shelf scales over which the mixed-layer depth varies. This report presents a summary in graphic and tabular form of the hydrographic observations made during cruise W8905 on the R/V Wecoma.Funding was provided by the National Science Foundation through Grant Number OCE 87-1693

CTD observations off northern California during the Shelf Mixed Layer Experiment, SMILE, November 1988

CTD observations on the R/V Wecoma cruise W8811 were made off the northern California coast November 13-24, 1988 as part of the .S.helf Mlxed Layer Experiment (SMILE). The survey consisted of repeated mappings of the central transect (C) through the SMILE moored array, and two synoptic sampling surveys-a large-scale grid of four cross-shelf transects extending to both sides ofPoint Arena and Point Reyes, and a small-scale grid of five cross-shelf transects located near the central SMILE mooring site. The small-scale hydrographic survey had a much higher spatial resolution of CTD stations than the large-scale survey. The primary objectives of the hydrographic measurement program were to observe and characterize the temperature, salinity, density, and light transmission fields and their temporal and spatial variability in the surface boundary layer along the continental shelf and slope near the SMILE moored array, and to acquire an estimate of the cross-shelf and along-shelf scales over which the mixed-layer depth varies. All of the cross-shelf transects extended beyond the shelf break and the maximum sampling depth at each station was near-bottom or 600 m. This report presents a summary in graphic and tabular form of the hydrographic observations made during cruise W8811 on the RN Wecoma.Funding was provided by the National Science Foundation through grant Number OCE 87-1693

CTD observations on the North Brazil shelf during a multidisciplinary Amazon Shelf Sediment Study, AMASSEDS, May-June 1990

Hydrographic (CTD) and acoustic Doppler current profiler (ADCP) observations were made on the North Brazil shelf adjacent to the mouth of the Amazon River during R/V Iselin cruise I9004 May 23-June 13, 1990 as part of A Multidisciplinary Amazon Shelf SEDiment Study (AMASSEDS). These observations were obtained during a small-scale survey on Leg 1 in support of mooring deployment operations, during a large-scale survey on Leg 3 in support of geological and geochemical sampling, during a frontal zone survey on Leg 4 consisting of 12 and 24 hourly CTD casts at anchored stations, and during a bottom tripod recovery on Leg 5. The maximum sampling depth at each station was within two meters of the bottom. The primary objectives of the AMASSEDS hydrographic measurement program were (a) to observe and characterize the temperature, salinity, density, oxygen, fluorescence and light transmission fields and their spatial variabilty on the North Brazilian shelf directly influenced by the Amazon River discharge, (b) to resolve the seaward extend and vertical structure of the surface plume of low salinity Amazon River water during different stages of river discharge, (c) to describe the spatial structure of the turbidity and associate suspended sediment distributions across the shelf, (d) to characterize the properties of the Amazon shelf water beneath the surface plume and their seasonal variabilty, and (e) to describe the landward penetration of the North Brazil Current with respect to water properties and shelf currents. This report represents a summary in graphic and tabular form of the hydrographic observations made during the third AMASSEDS cruise (I9004) on the R/V Iselin.Funding was provided by the National Science Foundation through Grant No. OCE 88-12917

An estimate of the cross-frontal transport at the shelf break of the East China Sea with the Finite Volume Coastal Ocean Model

Author Posting. © American Geophysical Union, 2006. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 111 (2006): C03012, doi:10.1029/2005JC003290.The Finite Volume Coastal Ocean Model (FVCOM) is used to estimate the onshore cross-frontal transport at the shelf break of the East China Sea. Boundary conditions of FVCOM are provided by the Princeton Ocean Model simulating ocean currents in the Yellow Sea and East China Sea realistically. One advantage of this study is that the unstructured triangular cell grid of FVCOM resolves complex bottom topography that may trigger Kuroshio frontal waves. It is anticipated that these nonlinear frontal waves enhance the exchange of seawater between the Kuroshio and shelf regions. Kuroshio frontal waves in the model are excited around the location where the bottom slope changes abruptly, and have the phase speed and amplitude consistent with those observed in the East China Sea. In addition, the model reproduces the onshore transport associated with growing frontal waves in the upper and lower layers. On the basis of passive tracer experiments, the annually averaged onshore-transport integrated along the shelf break is estimated to be 0.85 × 106 m3/s.This study was carried out when A. I. stayed at WHOI with the grant of Overseas Advanced Educational Research Practice Support Program supported by the Ministry of Education, Science and Culture, Japan. In addition, the Japan Society for the Promotion of Science supported this study through Grant-in-Aid for Scientific Research

CTD observations off Northern California during the Shelf Mixed Layer Experiment, SMILE, February/March 1989

CTD observations were made off the northern California coast during R/V Wecoma cruise W8902 February 22- March 10, 1989 as part of the Shelf Mixed Layer Experiment (SMILE). The surveys consisted of three sampling plans- a large-scale grid of four cross-shelf transects extending to both sides of Point Arena and Point Reyes, a small-scale grid of five cross-shelf transects located near the central SMILE mooring site, and an expanded small-scale grid of nine cross-shelf transects. All of the cross-shelf transects extended beyond the shelf break and the maximum sampling depth at each station was near-bottom or 1000 m. The average along-shelf separation between cross-shelf transects was about 15 km for the small-scale surveys and 50 km for the large-scale grid. The primary objectives of the hydrographic measurement program were to observe and characterize the temperature, salinity, density, and light transmission fields and their temporal and spatial variability in the surface boundary layer along the continental shelf and slope near the SMILE moored array, and to acquire estimates of the cross- and along-shelf scales over which the mixed-layer depth varies. This report presents a summary in graphic and tabular form of the hydrographic observations made during cruise W8902 on the R/V Wecoma.Funding was provided by the National Science Foundation through Grant Number OCE 87-1693

The seasonal hydrography and circulation over Nantucket Shoals

Bimonthly hydrographic surveys were begun in May, 1978 to measure the spatial structure and temporal variability of the temperature and salinity fields about Nantucket Shoals over one annual cycle. Moored current meters were also deployed in January, 1979 and in July, 1979 to directly measure the current field and examine low-frequency current variability over the shoals...

Tidal mixing and cross-frontal particle exchange over a finite amplitude asymmetric bank: A model study with application to Georges Bank

Tidal mixing, internal wave bores, and cross-bank particle transport over a finite amplitude asymmetric bank are examined using a two-dimensional primitive equation ocean model with Mellor and Yamada (level 2.5) turbulent closure. Driven by the surface M2 tide, the model results show that tidal mixing exhibits temporal and spatial asymmetries on southern and northern flanks of the bank. It is strongest near the bottom around maximum on-bank tidal flow as a result of gravitational instability when denser water is advected upslope over lighter water. A sharp thermal depression occurs on the steep northern flank, which produces large current shear and strong tidal mixing throughout the upper 50 m of the water column. Dissipation also exhibits a strong tidal variation, with the largest values (of order 10-5 W/kg) occurring near-bottom around maximum on- and off-bank tidal flow. Dissipation generally decreases upward, with a distinct phase lag in the vertical. Fluid particles are advected upslope near the bottom in the upper slope region (depth \u3c150 m) on both flanks, with some particles moving across the tidal mixing fronts near the bottom. The near-bottom residual Lagrangian current is opposite in direction to the residual Eulerian current on the northern flank due to strong nonlinearity over the steep bottom slope. The mean upslope advection of fluid particles near the bottom on both flanks is consistent with model passive tracer experiments, suggesting that strong tidal forcing of a stratified fluid over the bank can provide one physical mechanism responsible for high concentrations of nutrients and hence phytoplankton at the fronts on Georges Bank. The model predictions of eddy viscosity and turbulent dissipation rates are in good agreement with estimates based on recent current and microstructure measurements made on Georges Bank

CTD observations on the North Brazil shelf during a Multidisciplinary Amazon Shelf SEDiment Study (AMASSEDS) : February - March 1990

Hydrographic (CTD) and acoustic Doppler current profiler (ADCP) observations were made on the North Brazil shelf adjacent to the mouth of the Amazon River during R/V Iselin cruise I9002 February 10-March 29, 1990 as part of A Multidisciplinary Amazon Shelf SEDiment Study (AMASSEDS). These observations were obtained during a small-scale survey on Leg 1 in support of mooring deployment operations, during a lage-scale survey on Leg 3 in support of geological and geochemical sampling, during a frontal zone survey on Leg 4 consisting of 12 and 24 hourly CTD casts at anchored stations, and during a bottom tripod recovery on Leg 5. The maximum sampling depth at each station was within two meters of the bottom. The primary objectives of the AMASSEDS hydrographic measurement program were (a) to observe and characterize the temperature, salinity, density, oxygen, fluorescence and light transmission fields and their spatial variability on the North Brazilian shelf directly influence by the Amazon River discharge, (b) to resolve the seaward extent and vertical structure of the surface plume of low salinity Amazon River water during different stages of river discharge, (c) to describe the spatial structure of the turbidity and associate suspended sediment distributions across the shelf, (d) to characterize the properties of the Amazon shelf water beneath the surface plume and their seasonal variability, and (e) to describe the landward penetration of the North Brazil Current with respect to water properties and shelf currents. This report represents a summary in graphic and tabular form of the hydrographic observations made during the seond AMASSEDS cruise (I9002) on the R/V Iselin.Funding was provided by the National Science Foundation through Grant No. OCE 88-12917

A vector-averaging wind recorder (VWAR) system for surface meteorological measurements in CODE (Coastal Ocean Dynamics Experiment)

As part of the Coastal Ocean Dynamics Experiment (CODE) field program, moored buoys were instrumented to measure and record wind speed and direction, air and water temperature, insolation, barometric pressure and relative humidity. Appropriate sensors were selected, necessary modifications to the sensors and existing current meters were made, and Vector Averaging Wind Recorders (VAWRs) were assembled. R. M. Young utility rotor and vane wind sets designed by G. Gill, Paroscientific Digiquartz pressure sensors, Eppley pyranometers and Hy-Cal relative humidity and solar sensors were used in two field experiments . Standard VACM direction and temperature sensors were maintained in the wind recorders. Devices were constructed as needed to protect against measurement errors due to wind, sun and ocean spray. Four W.H.O.I. VAWRs with Gill wind sensor sets were deployed CODE-1 in 1981. Seven VAWRs were deployed in CODE-2 in 1982. A modified VMCM (Vector Measuring Current Meter) was used for comparison in CODE-1, and the seventh VAWR deployed in CODE-2 carried an integral sensor set for comparison. Although several VAWRs had minor problems, all but one VAWR in the two experiments returned useful scientific data.Funding was provided by and this report prepared for the National Science Foundation under grant Numbers OCE 80-14941 and OCE 84-17769