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NOAA Logo U.S. Dept. of Commerce / NOAA / OAR / ERL / PMEL


Recent Program Accomplishments
and Current Activities

Accomplishments during FY 95

TAO Project

The Tropical Atmosphere-Ocean (TAO) Array, consisting of approximately 70 deep-ocean moorings spanning the equatorial Pacific Ocean between 8N and 8S from 95W to 137E, was serviced and maintained. The purpose of the array is to provide high quality, in-situ, real-time data in the equatorial Pacific Ocean for short-term climate studies, most notably those relating to the El Nino/Southern Oscillation (ENSO) phenomenon. TAO measurements consist of surface winds, sea surface temperature, upper ocean temperature and currents, air temperature, and relative humidity. Recently, additional sensors have been added for incoming shortwave radiation, rainfall, and salinity. Data are telemetered in real time via Service Argos, and a subset of these data is placed on the Global Telecommunications System (GTS) for distribution to operational centers for assimilation into weather and climate forecast models.

TAO data support research efforts at institutions around the world on the causes and consequences of climate variability originating in the tropical Pacific. Variability in the equatorial Pacific during the 1991-95 has been characterized by three successive years of unusually warm surface temperatures. Work at PMEL during the past year has focused on describing the evolution of these warm events, analyzing the upper ocean heat balance in the western equatorial Pacific at 156E and the central equatorial Pacific at 140W, understanding the air-sea interaction and quantifying surface heat, moisture, and momentum fluxes, detecting equatorial Kelvin waves and Rossby waves, and understanding how these waves mediate the evolution of the warm events.

The TAO project provides interactive access to TAO display software and graphics via the World Wide Web and workstation-based TAO Display Software. The TAO software features a point-and-click interface and a data subscription service providing remote users with automated daily updates to real time and historical TAO data, and is actively used at nearly 50 research institutions throughout the world. In FY 95, the TAO project developed the El Nino Theme Page, which links El Nino-related data from widely distributed research institutes to present a coherent picture of the global ENSO phenomenon, enabling any user to browse and interact with the most recent data and forecasts, as well as with relevant scientific analyses and historical perspectives.

Thermal Modeling and Analysis Project

The Thermal Modeling and Analysis Project (TMAP) conducts ocean circulation model studies using observed and synthetic wind fields, carries out surface wind analyses, and establishes design specifications for the TAO array in the Pacific. During FY 95, the global patterns of surface variability during El Nino periods were evaluated to validate coupled ocean-atmosphere models needed for El Nino forecasting. Using the Geophysical Fluid Dynamics Laboratory (GFDL)-developed ocean circulation model, the processes responsible for the seasonal cycle of sea surface temperature (SST) and zonal currents in the equatorial waveguide were documented. This basic research contributes to our understanding of how variability during El Nino periods relates to that during "normal" periods.

A global parallel-computer model to study the uptake of chlorofluorocarbons (CFCs) during the 20th century was compared with PMEL CFC observations to document the model's strengths and weaknesses. This state-of-the-art look at how well ocean models simulate the exchange of chemicals between the atmosphere and the ocean is a central aspect of global warming research.

The FERRET software system, which was originally developed to support visualization by TMAP researchers, has become an increasingly popular analysis tool, and is currently used by an estimated 80 research groups in 20 countries. The FERRET software is also at the heart of a service that PMEL provides to the public over the World Wide Web, called Live Access to Climate Data. Using this service, users can easily "slice and dice" multi-dimensional data sets to obtain customized visualizations or to download data.

Radiatively Important Trace Species/Aerosol Monitoring Program

In order to be able to predict future atmospheric concentrations of radiatively important trace gas and aerosol species, climate-chemistry models must include accurate estimates of the sources of these gases to the atmosphere. Studies were conducted to determine the ocean's role in the atmospheric distributions of chemically reactive and infrared-active trace gases. Data from previous PMEL Pacific Ocean meridional transects (1987-1994) were used to reevaluate the open-ocean source of methane, carbon monoxide, and carbonyl sulfide.

The accuracy of the estimated radiative forcing due to tropospheric sulfate aerosol depends on the quality and spatial coverage of the data that serve as input to global climate models. Data from four PMEL field expeditions were used to document aerosol properties in the marine boundary layer over a wide range of latitudes, quantify aerosol precursor emissions and the processes controlling them, compare calculated and measured aerosol properties, and determine the processes controlling these properties.

As part of NOAA's Aerosol Monitoring Program, PMEL researchers collected and analyzed aerosol samples collected at Sable Island and Cheeka Peak. This work marks the start of a data record of variability at sites downwind and upwind of the continental U.S., and will serve as input for global climate models.

Carbon Dioxide Program

The primary objective of NOAA's Ocean Atmosphere Carbon Dioxide Exchange Study (OACES) is to quantitatively assess the fate of anthropogenic CO2 in the atmosphere and oceans. During FY 95, the PMEL CO2 group developed a model that quantitatively estimates the amount of anthropogenic CO2 that penetrates into the oceans on the basis of changes in dissolved inorganic carbon and other physical and chemical data collected over decadal time scales. From a comparison of the 1991 cruise data along 152W in the north Pacific with the 1973 GEOCHEMICAL OCEAN SECTIONS STUDY (GEOSECS) data, it was determined that the north Pacific Ocean accumulated anthropogenic CO2 in the mixed layer to a depth of approximately 1000 m.

The CO2 groups at PMEL and Atlantic Oceanographic & Meteorological Laboratories (AOML) also completed a 7-month cruise in the Indian Ocean, as part of the U.S. Joint Global Ocean Flux Study (JGOFS) Program in the Arabian Sea and the U.S. World Ocean Circulation Experiment (WOCE) Repeat Hydrographic Program. Over 4,100 samples were collected and analyzed for dissolved inorganic carbon, total alkalinity, CO2 partial pressure, and pH on south-north and east-west transects.

CFC Tracer and Large-Scale Ocean Circulation Programs

The PMEL CFC Tracer Program studies ocean circulation and mixing processes by measuring the distribution of dissolved chlorofluorocarbons (CFCs) in the ocean. Key long-term goals are to document the entry of CFCs from the atmosphere into the world ocean by means of repeat long-line hydrographic sections at decadal intervals, and to use these observations to help test and evaluate ocean-atmosphere models. Such models are critical for understanding the state of the ocean-atmosphere system, quantifying the ocean's role in the uptake of trace gases, and improving predictions of climate change. The 10-year repeat-section program is a prototype for a long-term system for monitoring and detecting change in the ocean on decadal time scales.

During FY 95, multi-institutional cruises were carried out in the Pacific, Atlantic, Indian, and Antarctic Oceans. In the Antarctic, cooling and sinking of surface seawater carries dissolved CFCs into the deep ocean. This CFC signal has been detected thousands of miles away, allowing the deep flow patterns to be traced and studied. Observations of dissolved CFC are being compared with models of ocean circulation to test whether the models are realistic.

Monitoring Transport of Ocean Currents

Ocean currents such as the Gulf Stream and Kuroshio are major transporters of equatorial heat to high latitudes. The transport of the Florida Current (the major contributor to the Gulf Stream) has been monitored since 1982 using the cross-stream voltages detected using out-of-service and in-service telephone cables across the northern end of the Straits of Florida (between West Palm Beach and the Bahamas) and, since 1990, using an out-of-service cable across the southwestern end of the Straits (between Key West and Havana). This procedure is a very inexpensive method for continuous long-term measurements of major ocean current systems. During FY 95, robust methods were developed and refined for removing the geomagnetically induced voltages, and collaborations were begun with oceanographers from Japan and Taiwan to help them start a program to monitor transport across the Kuroshio. In addition, a major numerical electromagnetic modeling effort was completed, establishing the relationship between voltages and transport for long transoceanic telephone cables.

PMEL Activities in the PACS Program

The Pan American Climate Studies (PACS) program, which began in mid-1995, is a NOAA initiative, to advance our ability to predict seasonal to interannual climate variability over the Americas. PMEL scientists are involved in both the observational and modeling aspects of the PACS program. It is expected that the TAO buoys in the eastern tropical Pacific will be used as platforms for PACS observations of the marine boundary layer. Under PACS, PMEL scientists have begun a project to use a newly developed ocean general circulation model (GCM) to diagnose the mechanisms controlling the annual cycle of sea surface temperature (SST) in the Pacific equatorial cold tongue region. During FY 95, the PMEL PACS research effort brought the new GCM to PMEL and developed a new I/O system to enable the model to be diagnosed with PMEL's Ferret analysis tool. The model was tuned to produce a baseline seasonal cycle run for the eastern tropical Pacific.

Fisheries-Oceanography Coordinated Investigations (FOCI) Program

An objective of FOCI is to translate scientific understanding into tools that can be used to manage stocks of commercially important fish and shellfish in Alaskan waters. FOCI collaborates in this effort with the Alaska Fisheries Science Center (AFSC) and the North Pacific Fishery Management Council. During FY 95, FOCI made its fourth annual prediction of recruitment (the number of fish spawned during 1995 that will survive to enter the fishery in 1997) of walleye pollock to the Shelikof Strait fishery. The 1995 year class is expected to experience average-to-strong recruitment.

FOCI's approach is to provide a qualitative forecast (e.g., weak, average, strong) that is used to define scenarios considered by AFSC's stock projection model. The forecast is developed from an evolving source of information and analytical models guided by FOCI's conceptual model of recruitment. This year, six sources of information were available: quantitative results from fitting of a nonlinear transfer function time series model, quantitative results from analysis of the time sequence of recruitment data points, and four qualitative sources of information (rainfall, wind mixing, advection, and an index of larval abundance). Although larval abundance was strong in 1995, environmental conditions during the early life stages of the fish indicated that only an average to average-to-strong year-class would survive. For the coming year's prediction, plans are to quantify qualitative forecasts from rainfall and wind mixing, and to explore promising analytical techniques such as intervention analysis, tree-modeling regression, and nonlinear response surface analysis. Analyses were completed on the Individual-Based Model (IBM) for Shelikof Strait in combination with a sophisticated ocean circulation model to study the early life history of pollock.

FOCI has begun a program of biophysical monitoring on the southeast Bering Sea shelf. Three moorings in different water depths, and thus different mixing regimes, were deployed from spring through summer. These moorings produce measurements of atmospheric forcing, currents and mixing, chlorophyll, and zooplankton backscatter. Time series provided the first opportunity to examine conditions prior to, during, and after an ice cover. The stabilization of the ice cover provided a spring bloom, which started early (April), compared to a solar insolation initiated bloom (May). Much of the biology of the Bering Shelf is conditioned by the temperature of the lowest half of the water column. The temperature of this cold pool can vary from 0C to 5C and is determined by climate conditions from the previous spring. Water temperatures below 2C are beyond the physiological limit for many species. The cold pool shows trends of 4 to 6 years, in addition to interannual variability.

Ocean Environmental Research (VENTS) Program

The Ocean Environmental Research Program is in its 12th 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. Since the Juan de Fuca and Gorda Ridges of the northeast Pacific are the portions of the mid-ocean ridge nearest to any continental land mass, this area has become the program's principal ocean laboratory. Research during FY 95 focused on five areas: (1) studies to determine regional transport, strength, and source of hydrothermal emissions and their relationships to the geological features of spreading centers, as well as understanding the effects of off-axis hydrothermal circulation on the ocean's geochemical balance, (2) development of capabilities for monitoring hydrothermal and geophysical activity at a wide range of temporal and spatial scales, (3) application of Geographic Information System (GIS) strategies to better utilize current disciplines, such as seafloor mapping technologies, (4) examination of the interplay of fluid chemistry with microbial processes, and (5) development of 3-D time-dependent nonhydrostatic models that describe deep-ocean hydrothermal plume formation.

Monitoring of the characteristics of hydrothermal plumes emanating from the northern Cleft vent field on the Juan de Fuca Ridge (JdFR) continued in FY 95. Since 1991, an array of 8-12 miniature temperature recorder (MTR) and current meter (CM) moorings have been successfully deployed and recovered at yearly intervals, making this effort by far the longest time series study of a particular vent field on the mid-ocean ridge. This time series study, in conjunction with other studies (e.g., hydrothermal discharge created in 1993 by seafloor volcanic eruptions on the CoAxial segment of the Juan de Fuca Ridge), will enable scientists to examine the life cycle of a hydrothermal vent field. Such studies are crucial for understanding the cooling history of magma beneath the ridge axis as well as the changes in chemical composition and origin of discharging fluids over the lifetime of a vent field. PMEL investigators, working with fellow scientists from the Universities of Hawaii and Miami, participated in the first sampling of hydrothermal emissions distant from the axis of a mid-ocean ridge. Hydrothermal venting was discovered on a 3.5-million-year-old basaltic-outcrop on the eastern flank of the Juan de Fuca Ridge. Because most of the earth's hydrothermal heat loss occurs on ridge flanks, the effect of off-axis hydrothermal circulation on the ocean's geochemical balance may be great. The effects of heating at the JdFR can be seen as far as 1000 km to the west, as observed by conductivity-temperature-depth (CTD) experiments. During FY 95, scientists mapped a shallow helium plume emanating from Loihi Seamount on the flanks of Hawaii. This plume can be traced for thousands of kilometers from Hawaii and indicates eastward transport in this region of the Pacific. This movement is in disagreement with conventional interpretation of ocean topography.

In 1991, PMEL initiated a joint agreement with the U.S. Navy to exploit the Navy's existing underwater listening arrays for environmental research. The use of SOSUS (SOund SUrveillance System) has allowed OERD (Ocean Environment Research Division) to monitor the low-level seismicity of the northeast Pacific and the very low-level volcanic seismicity of the northeast Pacific spreading center. In 1993, a major seafloor eruption was detected and located along the Juan de Fuca Ridge. Subsequent field investigations have greatly enhanced our understanding of undersea volcanism and seafloor spreading processes, and revealed a potentially large subseafloor ecosystem that could only be observed when the seafloor was disrupted by geological activity. During FY 95, this acoustic monitoring effort was expanded beyond the northeast Pacific to acquire all of the Navy's north Pacific arrays and transmit the data to PMEL's Newport, Oregon laboratories via telephone line. By broadening the coverage of the SOSUS monitoring, earthquakes have been accurately located as distant as the coasts of Chile and New Zealand. A volcanic eruption has also been continuously monitored in the Marianas Islands in the western Pacific. FY 95 also saw the completion and field testing of a new underwater, autonomous hydrophone mooring capable of monitoring long-range acoustics at the same sensitivity as SOSUS at any location in the world's oceans, but not in real time. In situ monitoring of ridge crest processes was carried out by measuring the volcanic system for vertical ground deformation and seismicity associated with movement of magma in the sub-seafloor. In FY 95, three Volcanic System Monitors (VSM) were deployed at Axial Seamount to record the nature of volcanic activity during an eruption. This effort supports long-range acoustic monitoring studies, providing valuable ground truth for SOSUS and moored hydrophone data sets. In addition, an array of new instruments called "Acoustic Extensometers" has been developed to precisely measure horizontal distances on the seafloor. The purpose of these instruments is to detect seafloor spreading events across the axis of a mid-ocean ridge and to establish relationships with other oceanographic and geophysical phenomena.

The intercomparison of multidisciplinary data sets, including geology, geophysics, acoustics, biology, physical oceanography, and ocean chemistry, has required the development of advanced Geographic Information System (GIS) technology for the use of program scientists. This allows the direct comparison of data sets of various forms and dimensions on interactive computer workstations. During FY 95, an advanced GIS system based on the ARCINFO package was assembled for use in studying the Juan de Fuca Ridge. Numerous data sets have been integrated into the system, including long-range acoustic monitoring data, seafloor mapping and imagery, seafloor geology, chemistry and biology.

Immense quantities of microorganisms (many of which thrive at temperatures above 100C) live in subseafloor environments exclusively associated with geophysically active regions of spreading centers. The genetic diversity of these microorganism ecosystems, and the high-temperature enzymes and metabolites they produce, have caught the attention of the biotechnology industries who see wide-ranging potential for biotechnical, biochemical, and pharmaceutical applications. In FY 95 collaborations continued with microbiologists at the University of Washington to examine the interplay of fluid chemistry with microbial processes. Increased efforts to coordinate sampling for chemistry, microbiology, and macrobiology helped scientists better understand how the chemical environment affects the microbial community and how microbial processes are reflected in fluid chemistry. The SUAVE in situ analyzer, along with sampling systems mounted on remotely operated vehicles, will be key components in the effort to maximize the chemical data collected over hydrothermally active areas rich in subseafloor microbial populations.

The dependence of plumes on the earth's rotation rate, the turbulence in the plume and the surrounding environment, and the speed of cross flow continues to be a factor in developing reliable 3-D time-dependent nonhydrostatic models that describe deep-ocean hydrothermal plume formation. These models also yield point-dense fields of all important variables, providing PMEL with the ability to investigate methodologies used in the analysis of field data. During FY 95 an effect was observed in laboratory and atmospheric plumes, from both industrial stacks and volcanos, that showed that plumes divide into two parts under the right conditions of buoyancy and cross-flow. This effect was reproduced in a model that may prove useful to applications of atmospheric as well as hydrothermal plume descriptions.

Tsunami Project

The PMEL Tsunami Project, 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. These programs 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, two of these applications involve improved development of site-specific tsunami inundation maps and a real-time reporting tsunami measurement system.

During FY 95, three oceanographic cruises were successfully completed to recover and redeploy bottom pressure recorders (BPRs) in the tsunami monitoring network. A deep-ocean BPR record of the October 4, 1994, Shikotan Tsunami was acquired off the U.S. west coast. In addition, a complete coastal gauge data set has also been collected off the Hawaiian, Alaskan, and western U.S. coasts as well as a number of Pacific Islands. Accuracy of bottom pressure observations acquired by a prototype real-time reporting system deployed off the Washington coast was also verified during the FY 95 field season.

The long duration of the April 25, 1992, Cape Mendocino Tsunami was convincingly explained in terms of a theoretical model involving trapped edge waves as part of the coastal response to the tsunami energy. Identification of this response mechanism has important practical implications for disaster management strategies to minimize death and injury in the aftermath of a main tsunami inundation event. This was a timely research result, in light of recent concerns regarding a possible future large earthquake and tsunami generated off the U.S. west coast in the Cascadia Subduction Zone.

BPR records of tsunamis generated by earthquakes in the Gulf of Alaska on November 30, 1987, and March 6, 1988, were inverted for fault-plane parameters and seismic moment. The tsunami waveform inversion provided an additional constraint on the rupture length of the latter event, demonstrating the supplementary value of tsunami data to analyses of earthquake finite-fault characteristics.

A report on ocean tides off the Pacific Northwest Shelf analyzed BPR measurements acquired off the Washington-Oregon coast and convincingly demonstrated the applicability of BPR measurements to studies of other important, non-tsunami scientific investigations, most notably tidal and other low-frequency sea level phenomena.

Activities during FY 96

TAO Project

Thermal Modeling and Analysis Project

Radiatively Important Trace Species/Aerosol Program

Carbon Dioxide Program

CFC Tracer and Large-Scale Ocean Circulation Programs

Monitoring Transport of Ocean Currents

PMEL Activities in the PACS Program

Fisheries-Oceanography Coordinated Investigations (FOCI)

Ocean Environment Research (VENTS)

Tsunami Project