This book is written for college juniors and seniors and new graduate students in meteorology, ocean engineering, and oceanography. It begins with a brief overview of what is known about the ocean. This is followed by a description of the ocean basins, for the shape of the seas influences the physical processes in the water. Next, students will study the external forces, wind and heat, acting on the ocean, and the ocean's response. It also includes the equations describing dynamic response of the ocean. For example, the equations of motion, the influence of earth's rotation, and viscosity. Finally, students consider some particular examples: the deep circulation, the equatorial ocean and El NiEœno, and the circulation of particular areas of the ocean. Contents: 1) A Voyage of Discovery. 2) The Historical Setting. 3) The Physical Setting. 4) Atmospheric Influences. 5) The Oceanic Heat Budget. 6) Temperature, Salinity and Density. 7) The Equations of Motion. 8) Equations of Motion with Viscosity. 9) Response of the Upper Ocean to Winds. 10) Geostrophic Currents. 11) Wind Driven Ocean Circulation. 12) Vorticity in the Ocean. 13) Deep Circulation in the Ocean. 14) Equatorial Processes. 15) Numerical Models. 16) Ocean Waves. 17) Coastal Processes and Tides.

Introduction to Physical Oceanography

The Bermuda Atlantic Time-series Study (BATS) commenced monthly sampling in October 1988 as part of the US Joint Global Ocean Flux Study (JGOFS) program. The goals of the US JGOFS time-series research are to better understand the basic processes that control ocean biogeochemistry on seasonal to decadal time-scales, determine the role of the oceans in the global carbon budget, and ultimately improve our ability to predict the effects of climate change on ecosystems. The BATS program samples the ocean on a biweekly to monthly basis, a strategy that resolves major seasonal patterns and interannual variability. The core cruises last 4-5 d during which hydrography, nutrients, particle flux, pigments and primary production, bacterioplankton abundance and production, and often complementary ancillary measurements are made. This overview focuses on patterns in ocean biology and biogeochemistry over a decade at the BATS site, concentrating on seasonal and interannual changes in community structure, and the physical forcing and other factors controlling the temporal dynamics. Significant seasonal and interannual variability in phytoplankton and bacterioplankton production, biomass, and community structure exists at BATS. No strong relationship exists between primary production and particle flux during the 10 yr record, with the relationship slightly improved by applying an artificial lag of 1 week between production and flux. The prokaryotic picoplankton regularly dominate the phytoplankton community; diatom blooms are rare but occur periodically in the BATS time series. The increase in Chi a concentrations during bloom periods is due to increases by most of the taxa present, rather than by any single group, and there is seasonal succession of phytoplankton. The bacterioplankton often dominate the living biomass, indicating the potential to consume large amounts of carbon and play a major ecological role within the microbial food web. Bacterial biomass, production, and specific growth rates are highest during summer. Size structure and composition of the plankton community may be an important factor controlling the quality of dissolved organic matter produced and could affect production of bacterioplankton biomass. Larger heterotrophic plankton play an integral role in the flux of material out of the euphotic zone at BATS. Protozoans are abundant and can constitute a sizable component of sinking flux. Zooplankton contribute significantly to flux via production of rapidly sinking fecal pellets, and vertically migrating zooplankton can actively transport a significant amount of dissolved organic and inorganic carbon and nitrogen to deep water. An important question that remains to be further addressed at BATS is how larger climatological events drive some of the interannual variability in the biogeochemistry. (C) 2001 Published by Elsevier Science Ltd.

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Overview of the US JGOFS Bermuda Atlantic Time-series Study (BATS): a decade-scale look at ocean biology and biogeochemistry

Seasonal cycles of pelagic production and consumption

Publisher Summary The presence of numerous seamounts in the world's oceans, especially in the Pacific, has only become known to the scientific community in the last 50 years. This chapter deals with the current knowledge on the effects of seamounts on pelagic ecosystems, factors that influence the structure of seamount communities, the establishment, maintenance and genetic isolation of populations on seamounts and on the effects of commercial exploitation on seamounts organisms. The reviews, addresses in the chapter, cover aspects of the biology of seamounts especially those in Keating et al., but this literature has had limited circulation amongst biologists. Moreover, this chapter also throws attention on seamounts especially in respect to the current topography interactions, the biology of the soft benthos on seamounts and on the biology of commercially valuable species of fish associated with seamounts. Finally, the combination of this new data with that obtained in previous studies provides a complete picture of the current knowledge of the biology of seamounts, which can be of use to marine biologists, fisheries biologists and oceanographers.

The Biology of Seamounts

Four variants of the Multiple Opening/Closing Net and Environmental Sensing System (MOCNESS) have been constructed to sample a broad size spectrum of oceanic animals from microzooplankton to micronekton. The systems differ in mouth opening dimensions (ranging from 1/4 to 20 m2), the number of nets carried (from 5 to 20), and the mesh size of the netting (from 64 μm to 3.0 mm). A new electronics package enables an operator to send commands down a single conductor, armored cable to open/close the nets and provides 12-bit resolution for the environmental (temperature, depth, conductivity) and net operation data (flow, net-frame angle, net-bar release), which are transmitted up the cable to the deck unit at 2-s intervals. A microcomputer system, interfaced to the deck unit, calculates salinity, volume filtered by a net, net trajectory velocity, and vertical velocity. The data are printed out and stored on disc, and profiles of temperature and salinity versus depth are plotted during the course of the tow. Analysis of the relationship between the geometry of the MOCNESS under tow and the past and present methods used to estimate the water filtered by a net revealed that significant bias is introduced when the ascent or descent angle of a net is disregarded. The bias is a function of the ratio of vertical velocity to net trajectory velocity and results in an underestimate of volume filtered while shooting a net and an overestimate while hauling.

New development in the MOCNESS, an apparatus for sampling zooplankton and micronekton

Gulf Stream cold-core rings: Their physics, chemistry, and biology

The trajectories of 16 satellite-tracked drifting buoys from February 1976 through May 1980 and their derived velocities are used to construct a Lagrangian realization of the near-surface circulation of the North Pacific subtropical gyre. A composite transit time around the periphery of this gyre is approximately 4.5 years at an average speed of 15 cm s−1. The details of the surface flow indicated regional differences in mesoscale energetics. Flow variability is low in the eastern and high in the western portions of the northern limb of the gyre. The highest mean speeds and minimum variances are found in the tropical currents of the southern limb. The drifter data is compared with the climatological mean field of dynamic topography (0/500 dbar). This comparison shows significant differences between drifter movement and inferred geostrophic flow. In the eastern mid-latitude region the direction of the drifter motion and dynamic topography is in good agreement; however, the drifter speeds are 5 times greater. In the eastern and southern branches of the gyre, the current magnitudes of the drifters and geostrophic flow are comparable but their directions diverge. Comparison of the drifter trajectories and climatological seasonal sea level pressure maps reveal that the trajectory departures from the dynamic topography can often be related to atmospheric forcing. In the eastern mid-latitudes, the large annual signal in the atmospheric westerlies correlates with a fivefold increase in drifter speeds from summer to winter. In the tropics, a small but persistent Ekman flow component causes the drifters to move northward from the equatorial regions where the mean geostrophic flow converges toward the equator. In the eastern limb of the gyre, response to the atmospheric forcing of the Pacific high pressure center causes the trajectories to cross isolines of dynamic topography. The drifters provide a unique insight into the spatial and temporal relationship of geostrophic and wind-driven flow components that influence the near-surface circulation of the subtropical gyre.

The near-surface circulation of the North Pacific using satellite tracked drifting buoys

Sea surface motion over an anticyclonic eddy on the Oyashio Front

Satellite techniques for measurement of sea surface temperature (SST) are reviewed briefly, and a discussion of satellite SST applications and recent research in oceanography is provided. These applications include the areas of climate, mesoscale oceanography, and fisheries. Examples given focus mainly on the Pacific and California Current regions. Satellite SST data are currently used operationally for fisheries applications and, in conjunction with in situ data, are providing new insights into mesoscale oceanographic phenomena. Requirements for sensor precision and calibration accuracy are more stringent in air-sea interaction studies and climate research, thus satellite data have gained only qualified acceptance for these applications. Improvements in future satellite instruments, more comprehensive in situ sensor deployments, and better data management procedures should eventually satisfy most oceanography and climate SST requirements.

Advances in satellite sea surface temperature measurement and oceanographic applications

Sea surface flow derived from displacements of surface patterns in sequential NOAA-6 AVHRR (11 micron band) satellite images yield coherent nonuniform distributions of velocity vectors, An analytic representation of flow over the region of the distribution is obtained by performing a least-squares regression analysis for coefficients of a streamfunction expansion that is expressed in terms of trigonometric bash functions. Sea surface topography is estimated with the streamfunction by employing a geostrophic approximation. An application is made to a portion of the Oyashio Frontal Zone in the northwestern Pacific that includes the First and Second Oyashio Intrusions and an anticyclonic eddy. A horizontal map of a local rotational perturbation property is calculated for this region as a further example of the use of the streamfunction analysis.

Andrew C. Vastano

Papers

Gulf Stream cold-core rings: Their physics, chemistry, and biology

The near-surface circulation of the North Pacific using satellite tracked drifting buoys

Sea surface motion over an anticyclonic eddy on the Oyashio Front

Advances in satellite sea surface temperature measurement and oceanographic applications

Sea Surface Topography Estimation with Infrared Satellite Imagery