U.S. Dept. of Commerce /NOAA / OAR / ERL / PMEL / Summary Report
U.S. Dept. of Commerce /NOAA / OAR / ERL / PMEL / Summary Report
The Pacific Marine Environmental Laboratory (PMEL) carries out interdisciplinary scientific investigations in oceanography, marine meteorology, and related subjects fundamental to NOAA's mission and Strategic Plan. Current PMEL programs focus on coastal and open-ocean observations in support of prediction of the ocean environment on time scales from days to decades. Studies are conducted to improve our understanding of the complex physical and geochemical processes operating in the world oceans, to define the forcing functions and the processes driving ocean circulation and the global climate system, and to improve environmental forecasting capabilities and other supporting services for marine commerce and fisheries.
PMEL complements its research efforts through two ERL cooperative institutes: the Joint Institute for the Study of the Atmosphere and Ocean (JISAO), with the University of Washington; and the Joint Institute for Marine and Atmospheric Research (JIMAR), with the University of Hawaii. PMEL also conducts complementary research programs with NOAA's National Marine Fisheries Service (NMFS) and the Cooperative Institute for Marine Resources Studies (CIMRS), a joint organization with Oregon State University.
The VENTS Program is in its eleventh year of research focused on determining the oceanic impacts and consequences of submarine hydrothermal venting. The program directs most of its efforts toward achieving an understanding of the chemical and thermal effects of venting along the northeast Pacific Ocean seafloor spreading centers. A modest effort, in collaboration with Japanese scientists, to study the fastest known midocean spreading system, on the southern East Pacific Rise (EPR), is also under way. The understanding obtained from these systems will eventually be extended to a prediction of the impact of seafloor hydrothermal systems on the global ocean. The attainment of the overall program goal requires a long-term interdisciplinary approach.
VENTS research during FY 94 was concentrated, as in past years, on (1) determining patterns and pathways for the regional transport of hydrothermal emissions as well as source strengths of the emissions and their relationships to the geology and tectonics of spreading centers, and (2) further developing capabilities for monitoring hydrothermal activity at a wide range of temporal and spatial scales. Research results obtained during FY 94 continued to augment the case for hydrothermal venting at seafloor spreading centers having global significance in terms of the chemical and thermal state of the ocean. NOAA VENTS Program scientists, together with their non-NOAA research collaborators, continued their success in quantitatively documenting these effects as they occur in the ocean over a wide range of temporal and spatial scales.
The VENTS Program extended to one year the monitoring of hydrothermal discharges at the CoAxial Segment that erupted in June 1993. This monitoring effort has documented a rapid decline in vent emissions, enabling us to study, in compressed form, the life cycle of a hydrothermal vent field. Such studies are crucial in understanding the changes in the chemical composition of discharging fluids over the lifetime of vent fields and will strongly bear on the global chemical impact of hydrothermal vents.
The CoAxial Segment event is unique in that it was the first seafloor eruption detected as it was happening. Time series observations and sampling at this site will show how a newly created hydrothermal system evolves. One result of interest is that some of the vent sites have been newly colonized by tube worms and other vent macrofauna, as observed in June 1994, just 1 year after the eruption. This is the first time that the colonization of a vent site has been documented.
The T-phase event detection system is a long-range acoustic surveillance tool that is providing a means to continuously monitor the northeast Pacific and virtually the entire Pacific basin through the use of the U.S. Navy's Integrated Underwater Surveillance System (IUSS). T-phases are acoustic signals that are generated by, among other things, submarine earthquakes and submarine volcanic eruptions. Detection of clusters of T-phases (earthquake swarms), which often accompany volcanic eruptions, is giving VENTS Program scientists the ability to study resultant episodic hydrothermal activity while it is still active. Results are showing that the volcanic system off the northwest coast of North American is at least 2 to 3 orders of magnitude more seismically active than was previously hypothesized on the basis of land-based seismic monitoring networks.
Volcanic eruptions continue to be documented. One was detected in the East Blanco Depression on the Blanco Fracture Zone during January 1994. This event was unusual in that it was along a strike-slip fault, which is not the typical geologic environment for volcanic activity. Subsequent investigations resulted in the discovery of large pillow-lava flows and an active hydrothermal vent.
Temporal and spatial monitoring of the effects of hydrothermal venting from midocean ridges continued during FY 94, the ninth consecutive year. This effort, concentrated in the northeast Pacific Ocean on the Cleft Segment of the Juan de Fuca Ridge (JDFR), represents the longest time series available anywhere on the midocean ridge. This time series has documented substantial changes in the hydrothermal discharge patterns, which are evidently related to the cooling history of magma beneath the ridge axis.
Miniature temperature recorder (MTR) mooring arrays established during FY 93 were successfully recovered, serviced, and redeployed for another year. The MTR moorings represent a continuation of full-time hydrothermal plume monitoring that began in FY 91.
The effects of heating at the JDFR may be seen at least as far as 1000 km to the west, as previously observed by conductivity, temperature, depth (CTD) observations. Chemical traces have been mapped to a longitude of 180°. These chemical traces are in the form of a helium isotope (helium-3) that originates from hydrothermal venting on the JDFR. Analyses of samples taken on several recent cruises have shown that the core of the effluent off the coasts of Oregon and Washington trends due southwest as it mixes into the north Pacific basin.
The PMEL Tsunami Project, as part of the Coastal Hazards element of NOAA's Coastal Ocean Program, seeks to mitigate tsunami hazards to Hawaii, California, Oregon, Washington, and Alaska through research aimed at improving operational products. Research efforts involve three tightly coupled programs, instrumental, observational, and modeling, which are designed to improve our fundamental understanding of tsunami generation, propagation, and inundation dynamics. The project is also involved in the application of this research to hazard mitigation, for example, demonstration projects to develop improved, site-specific, tsunami inundation maps and the development of a real-time reporting tsunami measurement system.
Three oceanographic cruises were successfully completed to recover and redeploy all bottom pressure recorders (BPRs) in the tsunami monitoring network. The project completed analyses of BPR accuracy including errors attributable to calibration and dynamic temperature response. A preliminary methodology has been developed to correct for such errors, and additional field and lab data analyses are planned.
A report was completed on the inundation modeling study of Crescent City and Eureka, California, which outlined a methodology for such studies and applied it to provide credible "worst case scenario" maps as guidance for local hazard mitigation officials.
The analysis of tides and other background water-level variations at Hilo, Hawaii, and Crescent City was completed. This analysis, which included the application of wavelet techniques to Crescent City, indicates that background water levels at these sites can have an important influence on the degree of tsunami inundation.
A report on the 25 April 1992 Cape Mendocino, California, tsunami was published. Though small, this tsunami was important because it occurred at the southern end of the Cascadia Subduction Zone. This zone is off the U.S. West Coast and is believed capable of sustaining a great earthquake, accompanied by a large destructive tsunami.
The U.S. tsunami research and operational observational measurement capabilities of the National Ocean Service (NOS), Office of Oceanic and Atmospheric Research (OAR), and the U.S. Army Corps of Engineers were summarized in a published report. System deficiencies were identified, and recommendations made for improvements.
A workshop to assess the state of the art of tsunami inundation modeling was held in November 1993. The technical report published from this workshop contains several recommendations for applying this technology to tsunami risk reduction for the United States.
A Tsunami Warning Systems Workshop was convened in September 1994 and focused on the problem of a large, destructive tsunami generated on the Cascadia Subduction Zone; on producing an inventory of existing warning capabilities; and on improvements to warning system technology that are needed to mitigate the U.S. West Coast hazard from such an event.
The goal of Fisheries-Oceanography Coordinated Investigations (FOCI) is to understand the coupled physical-biological interactions that affect survival of walleye pollock (Theragra chalcogramma) in Alaskan waters and ultimately lead to variations in recruitment. Recruitment is the process by which young fish are added to the adult or fished stock. FOCI directly supports NOAA's Strategic Plan to build sustainable fisheries. Research has been conducted in support of the paradigm that recruitment variations are largely a result of events during early life history, i.e., when pollock are larvae and juveniles. Our understanding of processes affecting recruitment has advanced to the degree that for the past 2 years FOCI provided U.S. fishery management with recruitment information for establishing pollock fishing quotas in the Gulf of Alaska. Recent observations of recruitment to the 1989 and 1990 year-classes verify the initial FOCI prediction. In fall 1994, FOCI again will supply estimates of pollock recruitment for the Gulf of Alaska.
Since the inception of FOCI in 1985, an interdisciplinary team of scientists has focused its research on Shelikof Strait, an important spawning locale for the commercially important Gulf of Alaska pollock. In FY 92 a Bering Sea component was added to FOCI under the auspices of NOAA's Coastal Ocean Program. Bering Sea research identifies the different aggregations of pollock, their relation to dominant circulation features of the Bering Sea, and the effects of basin, slope, and shelf habitats on the early life stages of pollock.
As a sign of FOCI's recognized success, the program was invited to provide a manuscript for inclusion in the American Geophysical Union's U.S. National Report: 1990-1994. FOCI made presentations both for NOAA and for the National Academy of Sciences during the year.
A stable, realistic, coupled biophysical model for Shelikof Strait is now operational. Agreement exists between modeled and observed features, particularly for longer-term currents and transport. These results direct future improvements of the physical component of the model, a semispectral primitive equation model (SPEM), in terms of timing of eddy formation and translation. Model results also show sensitivity to spatial variations in winds and thus reinforce the requirement to better define the wind field. The SPEM physical model has been successfully coupled to a spatially explicit, individual-based model (IBM) of pollock early life history stages. Results from the coupled model show that inclusion of mechanisms that determine the depths of individual eggs or larvae at particular times of their development are critical in determining direction of transport. This direction, in turn, determines the environmental factors to which each individual will be exposed, hence growth and survival. The IBM can produce observed bimodal larval distributions, something that simpler deterministic models cannot replicate. These results clarified the need for more knowledge of how primary and secondary production occur in time and space.
Analysis of current observations from 1991 was completed. Results establish continuity of transport from the vicinity of Prince William Sound through the Shelikof sea valley. Further, fluctuations in transport are dominated by basin-scale storms. These results imply that upstream sources exist for zooplankton (the prey of first feeding larvae) and that a need exists for more knowledge of orographic influences on large-scale winds.
Analysis of Advanced Very High Resolution Radiometer (AVHRR) satellite images from 1986 and 1989 has identified spatial and temporal patterns of surface currents in Shelikof Strait. The knowledge of these complex features assists in understanding and modeling pathways of transport both for early life history stages of pollock and for their prey items.
Results from these analyses, together with those from SPEM IBM studies suggested an experiment that was designed to refine our knowledge of the Shelikof Strait environment. Between March and September 1994, wind, current, chlorophyll, and water property observations were collected from four surface platforms, five satellite-tracked buoys, and eight subsurface moorings. Two dedicated research cruises sampled early- and late-stage larvae in environments providing contrasting conditions for larval survival.
Bering Sea FOCI (BS FOCI) has completed 4 years of a long-term environmental research program to reduce uncertainty in management of the Bering Sea walleye pollock fishery. Results support the International Convention on Conservation and Management of Pollock Resources and the North Pacific Fishery Management Council in their stewardship of Bering Sea resources and their allocation decisions on groundfish in the Bering Sea. The emphasis at the beginning of the project was on the deep basin and continental slope of the Bering Sea because little was known of their physical and biological environment and because there was major concern about the impact of fishing in the international waters of the central Bering Sea (the Donut Hole) on the total population structure of pollock in the Bering Sea. This task has been completed. FOCI and other fisheries information was used to help establish a moratorium on fishing in the Donut Hole.
Although there is large interannual variability in recruitment of pollock in the Bering Sea and much more to be learned about the fisheries ecology of the central basin, existing evidence suggests that the predominance of pollock recruitment is from the southeastern shelf. Fish in the basin were older, the larger populations of the mid-1980s were not replaced, and the food supply available for larval pollock appears to be less than adequate to support large, sustained aggregations.
During FY 94 BS FOCI was the primary fisheries-oceanography program cited during discussions of the NOAA Strategic Plan. BS FOCI has researched two subjects over the last year: stock structure of Bering Sea walleye pollock and recruitment processes affecting the walleye pollock population of the southeastern Bering Sea.
During FY 94 BS FOCI population studies progressed by completing a review of surveys of pollock distributions, establishing international agreements to share data and resources, and continuing promising development of a mitochondrial deoxyribonucleic acid (DNA) probe and a rapid restriction enzyme assay.
Research on recruitment mechanisms for walleye pollock in the Bering Sea advanced in several areas in FY 94. Analysis of historical distribution data on spawning and larval occurrences emphasized the importance of the southeast Bering Sea shelf as habitat for pollock larvae, and compared it with the adjacent basin and slope environments. Concurrently it was found that basin and slope waters do not provide sufficient copepod nauplii preferred by larvae for optimal growth; this suggests that basin waters cannot sustain large pollock populations. Through the FOCI Biophysical Platform (FOCI BP), which carries instruments for acoustic backscatter and chlorophyll measurements as well as an Acoustic Doppler Current Profiler (ADCP) and instruments for meteorological measurements, an understanding was gained of processes related to the development of the spring bloom, and this information was transferred to our biophysical modeling component. Through laboratory feeding experiments it was established that larvae can ingest protozoans, and through analysis of field samples it was demonstrated that sufficient densities of protozoans are present to support larval growth. Antibodies are being developed to assay the importance of various invertebrate predators on feeding larvae and to establish predator abundance in relation to environmental features. On the basis of findings presented at a FOCI-sponsored international workshop on juvenile pollock, a two-ship multidisciplinary study of juveniles was conducted in September 1994.
The Tropical Ocean Global Atmosphere (TOGA) Tropical Atmosphere Ocean (TAO) array of Autonomous Temperature Line Acquisition System (ATLAS) moorings and Profile Telemetry of Upper Ocean Currents (PROTEUS) moorings grew from 60 to 67 sites during FY 94. In addition, five ATLAS moorings along the equator were recovered for the final time in the western Pacific with the completion of the TOGA Coupled Ocean-Atmosphere Response Experiment (TOGA COARE). In the eastern Pacific, the time series at 0°, 110°W, which is the longest moored time series in the world ocean, now spans more than 14 years. The array is supported by five nations (United States, Japan, Korea, France, and Taiwan). The TAO array will be completed by the end of 1994; only two more sites remain to be occupied. TOGA TAO, providing basin-scale, real-time measurements of surface winds, sea surface temperature, and upper ocean temperature and currents, is recognized nationally and internationally as one of the great successes of the TOGA program. Moreover, the National Academy of Sciences Report on Ocean-Atmosphere Observations Supporting Short-term Climate Prediction states, beginning on page 1, that after TOGA ends in December 1994 "...the highest priority observing system for continuation is the TOGA-TAO Array in the Pacific." The array will be maintained in support of NOAA's Pan American Climate Studies (PACS) program, the U.S. Global Ocean, Atmosphere, Land System (GOALS) program and the international Climate Variability and Prediction (CLIVAR) program, which are scheduled for 1995-2010. TAO is also viewed as a contributor to the Global Ocean Observing System (GOOS) and Global Climate Observing System (GCOS).
In FY 94, approximately 20 articles using TAO data were submitted and/or published in refereed journals, in addition to approximately 60 technical reports, articles in meeting proceedings, published abstracts, and news articles. About half the publications involve PMEL authors. Research at PMEL has focused in part on a description of the most recent El Niño Southern Oscillation (ENSO) event that occurred during 1991-93. This event evolved differently from any previous ENSO in the past 40 years, and efforts are under way to diagnose the oceanic mechanisms involved in its development. TAO data have been used to study the processes affecting sea surface temperature variability in the cold tongue during 1991-93, indicating that equatorial upwelling is one of the dominant mechanisms responsible for ENSO-related warming and cooling in the eastern Pacific. Analyses also indicate that the evolution of the 1991-93 event was mediated by equatorial Kelvin and Rossby waves, although there were some differences between the observations of wave excitation and propagation, and expectations based on the "delayed oscillator" theory for ENSO. Reconciling these differences may provide clues into the very unusual nature of the 1991-93 event, which spanned three calendar years and was characterized by two major warming episodes in the eastern Pacific. Other studies include examination of the statistics of rainfall variability in the western equatorial Pacific; the role of shallow, rainfall-induced haloclines in reducing the downward mixing of heat in that region; the relationship of evaporation minus precipitation to surface layer salinity across the width of the equatorial Pacific on seasonal to interannual time scales; the relationship between diurnal heating, internal mixing, and internal waves in the equatorial cold tongue; descriptive and diagnostic studies of the annual cycle of currents and temperature along the equator; the role of instability waves in determining upper ocean temperature variability in the eastern equatorial Pacific; validation of sea level measurements from the Topographic Experiment (TOPEX)/POSEIDON altimeter; scale analyses of upper ocean thermal variability using moored time series data, with a view toward improving thermal field sampling strategies for short-term climate studies; and research into methods of assimilating data into ocean models used for short-term climate forecasting.
A new release of the TAO software, made during FY 94, has dramatically expanded TOGA TAO buoy data access. Now, in addition to real-time data, gridded, historical temperature and current meter data are available in the form of multiple space-time slices through the data from the TAO array. Variables plotted include those measured by the buoy and several computed quantities, and hourly surface measurements are available for the first time. The user has extensive control over relevant graphing parameters, such as the time axis, variable axes, vector scaling, and contour levels. Paper or transparency copies of all plots can be made by a single mouse click, and information about the data and software is available with a new "Help" button. Animations include observational data fields, National Meteorological Center (NMC) model-generated data fields, and TOGA drifting buoy data, and a sophisticated data subscription service provides remote users with automatic updates of selected datasets. The TAO software is in use at more than 40 oceanographic and meteorological institutions world wide.
Real-time TAO data and animations and related information about the TAO array and project have been made available via Mosaic pages, where data displays include data acquired during the previous night. Mosaic software tools, developed by PMEL's computer support division in support of TAO data access, have been incorporated into a general-purpose PMEL Mosaic utilities library, for use by other PMEL projects.
The FERRET program, which was originally developed by the Thermal Modeling and Analysis Project (TMAP) as a tool for the analysis of model results, has received direct funding from the NOAA Earth System Data and Information Management (ESDIM) program. Under this proposal two projects have been pursued that make FERRET's capabilities and TMAP's extensive climatological database available to a broader community of users: (1) a Mosaic interface gives all Internet users the ability to view and extract data from the database; and (2) a Motif-based point and click interface is half completed to make FERRET friendly for users who do not wish to learn the command language. FERRET is currently installed at more than 40 research institutions internationally and is freely available over the Internet. A new 180 page Users' Guide has been written and distributed.
The primary objective of NOAA's Ocean-Atmosphere Carbon Exchange Study (OACES)
is to quantitatively assess the fate of CO in the atmosphere and oceans. To do this requires
that the natural sources and sinks of carbon dioxide be determined. The PMEL CO
group
completed a 3-month cruise in spring 1994 in the eastern Pacific Ocean under the auspices of
NOAA's Climate and Global Change Program. The three-legged cruise, conducted aboard
NOAA research vessel Discoverer, was a part of the U.S. World Ocean Circulation
Experiment (WOCE) Hydrographic Program (WOCE line P18), supported jointly by NOAA
and the National Science Foundation. During the experiment, the scientists determined the
concentrations of carbon species and related physical and biological parameters on a
south-north transect along 103° 110°W from 67°S to 23°N.
Surface-to-bottom CO
profiles were obtained at most of the stations. More than 3800
samples were collected and analyzed for dissolved inorganic carbon (DIC), total alkalinity
(TAlk), CO
partial pressure (pCO
), and pH. The data collected from this cruise represent
the most comprehensive set of chemical and hydrographic measurements available for the
eastern South Pacific Ocean. The DIC measurements were accurate to within 1 1.5 ‘mol kg
1, based on analysis of reference materials and replicate samples. Preliminary results show
that the highest concentrations of DIC are observed at intermediate depths within the Pacific
Deep Water in the northern latitudes. In the high southern latitudes evidence of North Atlantic
Deep Water penetration into the deep Pacific can be observed in the salinity and DIC data.
The increase in DIC concentrations near the equator relative to similar data obtained during
cruises in the spring of 1992 suggests that non-ENSO conditions returned to the eastern
equatorial Pacific in 1994. The data from this cruise will be combined with other datasets
from the WOCE Hydrographic Program to constrain models of basinwide circulation and
carbon flux in the Pacific Ocean. This data set will be used in combination with NOAA data
from the same region taken in 1989 to access recent changes in carbon chemistry of the South
Pacific.
The PMEL Chlorofluorocarbon (CFC) Tracer Program has been using dissolved CFCs as
tracers of ocean circulation and mixing processes. Studies of the entry of CFCs and other
transient tracers into the ocean provide a unique description of the time-integrated circulation
of the ocean on decadal time scales. The central goals of the CFC program are to document
the entry of these compounds into the world ocean, by means of repeat long-line hydrographic
sections at 5-year intervals, and to use these observations to help test and evaluate
ocean-atmosphere models. The development and testing of such models is critical for
understanding the present state of the ocean-atmosphere system, quantifying the ocean's role
in the uptake of climatically important trace gases such as CO, and improving predictions of
climate change for the coming century. The 5-year repeat section program for CFCs and
carbon dioxide (and other tracers), begun at PMEL in the 1980s, serves as a prototype for a
long-term system for monitoring and detecting change in the ocean on decadal time scales.
In FY 94, the PMEL CFC Tracer group organized and helped successfully complete a
multi-institutional oceanographic expedition on NOAA ship Discoverer, as part of WOCE.
This section (designated WOCE line P18) extended along 103° 110°W from
67°S to 23°N, and included more than 184 stations. The full suite of
recommended WOCE measurements were included on this expedition, and the quality of the
data collected should fully meet all WOCE standards. The P18 section was a repeat of a
section previously occupied by NOAA in 1989. The PMEL CFC Tracer group also
participated in WOCE line P21W, a 2-month expedition in the central and western Pacific.
This work represents a major contribution by NOAA to the WOCE program. The PMEL CFC
Tracer group helped establish a dissolved-nutrient program at PMEL, and supported an
analytical facility for the high-accuracy measurement of dissolved oxygen. These
measurements are critical in understanding and interpreting the tracer and carbon distributions
observed along the hydrographic sections. The third year of a NOAA Atlantic Climate
Change Program (ACCP)-supported program to monitor variability of dense water formation
and ventilation processes in the Greenland-Iceland-Norwegian Seas, using CFCs and
helium/tritium as tracers was completed.
PMEL tracer and hydrographic datasets were put into digital format and made accessible via the Internet. Collaborative programs were continued with researchers at the NOAA/ERL Geophysical Fluid Dynamics Laboratory (GFDL) to utilize the CFC datasets in numerical models of ocean circulation. A new collaborative program was begun with researchers at the National Center for Atmospheric Research (NCAR) to utilize CFC data in global eddy-resolving models of ocean circulation.
Work continued on the development of techniques for the long-term storage of dissolved CFC samples and on the improvement of analytical techniques for measuring CFCs in the atmosphere and ocean.
The PMEL Atmospheric Chemistry Program consists of a trace gas (Radiatively Important Trace Species or RITS) and an aerosol component. The primary objectives of the RITS program include determining the variability in surface seawater and atmospheric concentrations of climatically important gas-phase species, the importance of the ocean as a source of these species, and the factors controlling the oceanic production and emission of these species to the atmosphere. The ultimate goal is to provide data necessary to test global climate models and to reduce the uncertainties in calculating climate forcing on decadal time scales. During FY 94 in the austral summer, PMEL conducted a cruise from the Gulf of Alaska to Antarctica to address each of these objectives. Seasonal differences were investigated by comparing the results from this cruise with those from an FY 93 cruise that took place in the austral fall.
PMEL's aerosol program is designed to study the production of atmospheric aerosol particles from gases that are emitted from the ocean, the growth and transformation of these particles, their spatial and temporal variability, and their climatic effects. Information obtained about aerosol chemical, physical, and optical properties will be available to serve as input to global climate models that include the climatic effects of atmospheric aerosol. Measurements were made during the FY 94 cruise as a part of this ongoing study. Work continued in conjunction with the NOAA/ERL Climate Monitoring and Diagnostics Laboratory (CMDL) on assessing the influence of continental sources on the distribution and climatic effects of aerosols at the NOAA aerosol monitoring sites in North America. In addition, a new research effort was initiated to study the effects of ammonia on the formation and growth of aerosol particles.
Transport variations in the Florida Current by cross-stream voltages are continuing to be monitored using an abandoned cable between Key West, Florida, and Havana, Cuba, and an in-service cable between West Palm Beach, Florida, and Eight Mile Rock, Grand Bahama Island. The accuracy of the in-service voltages was upgraded by installing voltage recorders and a reference electrode at Eight Mile Rock to improve the accuracy of the voltage measurements being made at West Palm Beach. The voltage-derived transports from these cables are being used by Dynalysis of Princeton as a southern boundary condition for modeling the shelf circulation off the East Coast of the United States. This model is being used for pollution studies. The transport values are also being used to evaluate numerical models being developed for climate studies. Voltage measurements are also continuing for the Newfoundland cables that extend into the Labrador Sea. It is too early to evaluate transport variations in that region because only several months of data have been collected. Numerical models that can compute voltages for any cable using a numerically generated North Atlantic circulation are being developed under the auspices of the Community Modeling Effort and using a realistic geophysical model of the ocean topography, sea floor sediments, and continental and crustal material. PMEL has developed, for the first time, a self-consistent model of the electromagnetic fields generated by a realistic circulation model containing bottom topography. This modeling effort shows that long cables in the North Atlantic can be used to monitor the net north-south transport between the ends of the cable.
| 1993 | ||
| 5 October | Dr. Bill Large NCAR Boulder, CO |
Development, verification, and application of an oceanic planetary boundary layer model |
| 14 October | Dr. Jabe Breland University of S Florida St. Petersberg, FL |
Development of spectrophotometric methods for the determination of sea water pH and alkalinity |
| 25 October | Dr. Calvin Mordy Hancock Institute for Marine Studies, USC |
Microbial production in Antarctic pack inc: Studies from the US-Russian drifting ice station |
| 28 Otober | Drs. Eddie Bernard and Frank Gonzalez PMEL Seattle, WA |
The July 1993 Hokkaido earthquke tsunami |
| 2 November | Valentin Koropalov Russian Institute of Nature Conservation and Nature Reserves |
Environmental impact assessment of oil and gas development in the Barents Sea |
| 4 November | Dr. Yevgeniy Kulikov State Oceanographic Institute MOSCOW |
Tsunami bottom pressure recorder measurements |
| 9 November | Dr. Clara Deser University of Colorado Boulder, CO |
Diurnal cycles of surface wind, air and sea temperature in the equatorial Pacific |
| 23 November | Dr. Alejandro Orsi Texas A&M; University College Station, TX |
On the extent and frontal structure of the Antarctic circumpolar current |
| 13 December | Dr. Joseph Pedlosky Woods Hole Oceanographic Institution Woods Hole, MA |
Baroclinic abyssal circulation structure |
| 1994 | ||
| 16 February | Dr. L. Yurganov Institute of Atmospheric Physics Russian Academy of Sciences Moscow, Russia |
Solar Spectroscopic measurements of carbon monoxide and long-term CO variations over Russia |
| 2 March | Dr. Shoichiro Nakamoto Japan Marine Science and Technology Center (JAMSTEC) Yokosuka, Japan |
Spatial sampling requirements for tropical Pacific SST variability |
| 3 March | Dr. J.P. McCreary Nova University Oceanographic Center Dania, FL |
The interaction between the subtropical and equatorial ocean gyres: the subtropical cell |
| 8 April | Dr. Abraham Oort NOAA/GFDL |
Estimates of the energy cycle in the world ocean |
| 14 April | Dr. Gary Lagerloef SAIC Bellevue, WA |
Interdecadal variations in the Alaska gyre and the role of Ekman Pumping |
| 17 June | Dr. Trevor McDougall CSIRO Hobart, Australia |
On the labelling of hydrographic data with neutral density: A computer algorithm for best-practice "isopycnals" |
| 14 July | Dr. Susan Wijffels Woods Hole Oceanographic Institution Woods Hole, MA |
A view of the circulation at 10°N in the Pacific: The tropical gyre and what's below it |
| 28 July | Dr. Guy Gelfenbaum USGS Center for Coastal Geology St. Petersburg, FL |
Sediment dispersal and flow in bouyant plumes |
| 16 August | Dr. Paul Novelli CIRES, University of Colorado Boulder, CO | Carbon monoxide in the troposphere: Distributions and trends |
| 19 August | Prof. Nobua Shuto Dept. of Civil Engineering Tohoku University Sendai, Japan |
Numerical simulation to aid field surveys, and field surveys to complete numerical simulation--the case of the 1993 Hokkaido tsunami |
| 22 August | Dr. Jim Johnson JISAO, University of Washington Seattle, WA |
Diurnal cycles of photochemically active atmospheric trace gases in the marine boundary layer |
| 26 August | Dr. Kathie Kelly Woods Hole Oceanographic Institution Woods Hole, MA |
Atmosphere/ocean coupling in mid-latitude western boundary currents |
| 8 September | Prof. Shoshiro Minobe Hokkaido University Sapporo, Japan |
Annual westward propagating signals in wind anomalies from the zonal mean in the tropical Pacific |
| 29 September | Dr. Harilaos Loukos Laboratoire d'Oceanographie Dynamique et de Climatologie CNRS/ORSTOM/Pierre et Marie Curie University |
The oceanic carbon cycel in the equatorial Atlantic. Simulation of the focal years (1982-1984) with the LODYC's OGCM |
