GOAL: Rebuild Sustainable Fisheries
Objective 1: Eliminate and Prevent Overfishing and Overcapitalization
Performance Measure: By 2004, 50% (86 of 269) fewer overfished fisheries (stocks subject ot overfishing)
Purpose: The impact of recent oceanographic changes on U.S. Bering Sea fisheries was the major focus of the Fisheries-Oceanography Coordinated Investigations (FOCI) International Symposium on Recent Conditions in the Bering Sea held November 9-10, 1998, at NOAA's Western Regional Center in Seattle, Washington. Sponsored by the joint OAR/NMFS FOCI program, the goal of the symposium was to investigate the causes and consequences of anomalous oceanographic conditions and their impacts on U.S. Bering Sea fisheries. This ecosystem is of particular significance because the eastern Bering Sea provides almost half of the fish and shellfish caught in the United States. Besides producing abundant fish and shellfish, the region also supports major populations of resident and migratory seabirds and marine mammals.
Over 70 participants, including scientists, administrators, resource managers, native Alaskans, environmentalists, and fishing industry representatives came together to discuss possible causes for recent environmental events and to recommend research activities required to better understand, monitor, and predict the impacts of these changes. Participants also investigated methods to report new events and to facilitate communication among scientists, industry, and the public, including the need for web-based, real- time data and information dissemination. Observations presented at the symposium indicated that atmospheric processes in 1997, partially in response to El Niño, resulted in clearer skies, calmer seas, and significantly warmer sea temperatures (by as much as 4 degrees Celsius or 8 degrees Fahrenheit) than normally observed in the eastern Bering Sea. The warmest water temperatures ever recorded on the eastern Bering Sea shelf were observed during the summer of 1997.
Perhaps the most striking event described at the workshop was the appearance of extensive areas of milky, aquamarine water, which covered over most of the Bering Sea shelf during 1997. The unusual color was caused by a massive bloom of coccolithophores, which have not previously been observed in the Bering Sea. Coccolithophores were shown to have replaced the normal summer plankton community. The effects of this bloom on the remainder of the food web are, as yet, not well understood. Remnants of the coccolithophore bloom were visible in satellite images during late winter and early spring of 1998, and another large bloom appeared during the summer of 1998 despite stormier weather and cooler surface water temperatures than observed during 1997.
Other changes in the ecosystem described during the symposium included unprecedented mortality of short- tailed shearwaters and severe reductions in reproduction rates for kittiwakes. Both are common seabirds frequenting the Bering Sea shelf during summer months. Commercial salmon runs were far below predicted levels. Salmon were also smaller than average, and did not follow traditional migratory patterns. There were unusual sightings of Pacific white-sided dolphins in Bristol Bay and unusually large numbers of baleen whales were observed on the Bering Sea shelf.
Although anomalous conditions did not seem to have an immediate effect on groundfish in the area, they may impact future abundance. National Marine Fisheries Service surveys in 1997 and 1998 located fewer juvenile, young-of-the-year pollock than observed in previous years. However, other studies conducted in 1998 suggest that young pollock, in fact, were quite abundant but located further onto the shelf than usual. This displacement could derive from transport of pollock larvae northeastward from their spawning area due to windy conditions during spring. The full ramifications of these recent changes won't be fully understood for several years, until the young pollock begin to mature into adult fish and enter the commercial fishery.
To meet the challenge of understanding and managing diverse populations of fish, marine mammals, and birds in a fluctuating and highly variable oceanographic environment, the task ahead is to better understand the linkages between the anomalous oceanographic conditions and selected Bering Sea living marine resources. Symposium participants agreed that focused, long-term, integrated research is required, and recommended adoption of the research activities outlined in the Draft Science Plan for the Bering Sea Ecosystem . Proceedings of the FOCI symposium are available on the Bering Sea and North Pacific Ocean web site.
Milestone(Q4): Develop and improve methods for gathering and using information relating to fisheries management including DNA sequencing, radiometric aging, time series data on fisheries and oceanographic data, and advanced simulation models to help: conceptualize stock assessment strategies, determine the relationships between biological and physical factors, and provide information to fishery managers. (SG, J. McVey; PMEL, P. Stabeno)
GOAL: Advance Short-Term Warning and Forecast Services
Objective 1: Enhance Observations and Prediction
Purpose: Current tsunami warnings are based on seismic data and coastal tide gage observations. But neither provides direct measurement of tsunami energy propagating toward coastal communities. As a consequence, an understandably conservative tsunami warning philosophy has produced an unacceptably high false alarm rate -- approximately 75% since 1950. These false alarms are a serious problem because they are expensive, they undermine the credibility of the warning system, and they place citizens at physical risk of accidental injury or death during an evacuation.
The speed and accuracy of tsunami warnings can be improved by real-time reports of deep ocean tsunami data collected near the source region within a few minutes of generation. NOAA's Deep-ocean Assessment and Reporting of Tsunamis (DART) Project is an effort of the U.S. National Tsunami Hazard Mitigation Program to develop this early tsunami detection and real-time reporting capability -- a formidable technological and logistical challenge. These data will enable a more direct and rapid assessment of the hazard and, when coupled with model forecasting tools, a more accurate prediction of the impact on specific coastal communities. For example, Hawaii Civil Defense must make evacuation decisions within an hour of a large earthquake in the Alaska Aleutian Subduction Zone (AASZ); DART stations between the AASZ and Hawaii will provide tsunami measurements before that decision must be made, so that destructive tsunamis will be identified more reliably and the number of false alarms and unnecessary evacuations will be reduced.
An added benefit of the real-time DART data stream is continued offshore tsunami monitoring. Dangerous conditions can persist for several hours after the first wave strikes a community. This is because very large tsunamis can have periods as long as an hour and the largest wave may arrive as late as the third or fourth in a series. So offshore tsunami monitoring will provide important guidance for decision-makers, who must judge the risk of deploying rescue and recovery personnel and equipment and, when the area is safe for the return of residents, sound the "all clear."
This milestone was undertaken because it is a logical and essential step in the establishment of a DART buoy network to provide early detection and real-time reporting of deep-ocean tsunamis. This milestone's goal was simple -- to successfully deploy and maintain a prototype DART station which would reliably acquire and report sea level data in real-time. Finally, this milestone contributes to the NOAA Strategic Plan's Advance Short-Term Warning and Forecast objectives in an obvious way -- i.e., it provides a capability that will aid NOAA efforts to observe, understand, and model the environment, develop a total environmental prediction system, and effectively disseminate products and services to users.
Efforts: In order to increase data transmission reliability to the high level expected of operational systems, a new improved DART prototype was designed, fabricated, and tested by PMEL's Engineering Division. This new version featured redundant data transmission paths, to reduce data losses.
Customers: NOAA bears primary responsibility for U.S. tsunami hazard mitigation, so that the primary customers of DART data are NOAA's tsunami warning centers -- the Pacific Tsunami Warning Center and the West Coast and Alaska Tsunami Warning Center. Secondary customers include the tsunami research and hazard mitigation community, including State entities, especially emergency management organizations and academic institutions. Finally, tertiary customers may include individuals conducting research on ocean tides and other low frequency sea level phenomena. The data will be disseminated initially via the World Wide Web. Eventually, PTWC and WC&ATWC plan to have their own direct satellite data downlink.
Significance: A major achievement of this effort has been the successful development of the seafloor-to-surface acoustic data transmission link for the deep ocean. This has never been done before, and the new capability represents a major advance in deep-ocean mooring and real-time monitoring technology.
Success: This milestone was completed in May, 1999, when the new prototype DART buoy was successfully deployed off Moss Landing, CA (36.5N, 122.6W). Since then, this system has provided a highly reliable real-time sea level data stream, with the observations available for viewing on the WWW.
Next Steps: In October, three DART stations will be established in the North Pacific; two will be sited south of the Shumagin Islands, Alaska (at 50.5N, 165.0W and 52.5N, 157.2W), the third at Ocean Station Papa (50.0N, 145.0W). These are part of a planned six-station network to be established by 2001, designed to provide early detection and measurement of tsunamis generated in the primary source regions that threaten U.S. coastal communities: the Alaska Aleutian Subduction Zone, the Cascadia Subduction Zone, and the South American Seismic Zone.
GOAL: Document, Predict, and Assess Decadal-to-Centennial Change
Objective 1: Characterize the Forcing Agents of Climate Change
Performance Measure: Results of 90% of the research activities are to be cited in the year-2000 IPCC
Third Assessment of Climate Change.
Subject: Monitoring, Process Studies, and Modeling Associated with Climate-Related Aerosols
Purpose: Atmospheric aerosol particles affect the Earth's radiative balance both
directly by scattering and absorbing solar radiation and indirectly by modifying the optical properties
and lifetime of clouds .
Although aerosols have a potential climatic importance over and down wind of industrial regions that
is equal to that of anthropogenic greenhouse gases [IPCC, 1996], they are still poorly characterized
in global climate models. This is a result of a lack of both globally distributed data and a clear
understanding of the processes linking gaseous precursor emissions, atmospheric aerosol properties,
and the spectra of aerosol optical depth and cloud reflectivity. At this time, tropospheric aerosols
pose one of the largest uncertainties in model calculations of climate forcing [IPCC, 1996]. This
uncertainty significantly limits our ability to assess the effect of natural and human induced changes
in the chemistry of the atmosphere on global climate.
Efforts: The International Global Atmospheric Chemistry (IGAC) Program's Aerosol Characterization Experiments (ACE) are designed to contribute to a better predictive understanding of the role of anthropogenic aerosols in climate forcing. ACE 2 focused on the radiative effects and controlling processes of anthropogenic aerosols from Europe and desert dust from the Africa as they were transported over the North Atlantic Ocean. The experiment, which took place in June/July 1997, involved over 250 research scientists from Europe and the United States. It included 60 coordinated aircraft missions with six aircraft, one ship, five satellites, and ground stations on Tenerife, Portugal and Madeira. NOAA-PMEL coordinated the shipboard measurements aboard the Ukranian Research Vessel, Professor Vodyanitskiy.
Customers: The ACE 2 data sets are now being used to evaluate numerical models that extrapolate aerosol properties and processes from local to regional and hemispheric scales, and assess the regional direct and indirect radiative forcing by aerosols.
Significance: The initial results from ACE 2 have been summarized in 48 research articles that have been submitted to Tellus for a special issue that will appear in early 2000.
Success: Highlights of the NOAA results include: (1) Based on the chemical, physical, and optical aerosol properties measured during ACE 1 and ACE 2, aerosol in the ACE 2 region was impacted by continental emissions even during periods of marine flow. During ACE 1 sea salt controlled the optical properties of both the sub- and supermicron aerosol. Sea salt concentrations were similar during ACE 1 and ACE 2 but sea salt had relatively less influence on aerosol properties during ACE 2 because of the larger degree of continental influence. (2) Sulfate aerosol concentrations during marine flow were about 4 times larger during ACE 2 than during ACE 1. Continental concentrations during ACE 2 were an order of magnitude larger than marine concentrations. The larger concentrations of sulfate measured during ACE 2 indicate the degree to which anthropogenic sources from North America and/or Europe impact the NE Atlantic even under conditions of marine flow. (3) The smaller role of sea salt during ACE 2 also was observed in measured aerosol optical properties. The spectral dependence of light scattering by particles indicated the strong influence of smaller fine mode rather than larger coarse mode particles during ACE 2. In addition, the single scattering albedo indicated the presence of a more absorbing aerosol than sea salt during ACE 2. (4) The amount of carbon-containing aerosol and the identity of the carbon species are large unknowns that contribute to the uncertainty in estimates of aerosol radiative forcing. A previous IGAC experiment in the Western Atlantic (TARFOX) found sulfate to total carbon ratios of 1.6 +/- 0.7 at altitudes below 300 m. Shipboard measurements during ACE 2 revealed a ratio of 2.9 +/- 1.3. The average sulfate concentrations from the two regions were comparable but the total carbon concentration during TARFOX was larger. This type of data helps us start to understand differences in the aerosol chemical composition for different ocean regions.
Next Steps: Planning is well underway for ACE-Asia that will focus on the region downwind of the rapidly increasing pollution sources in eastern Asia.
Objective 2: Understand the Role of the Oceans in Global Change
Subject: Track Climatically Important Oceanic Variability
Purpose: The Tropical Atmosphere Ocean (TAO) array is a key element of NOAA's recently completed ENSO observing system. In a collaborative project sponsored by the NOAA Office of Global Programs, MBARI, PMEL, and AOML scientists developed and deployed chemical and biological sensors for the Ka'imimoana and the TAO array to obtain a better understanding of the physical and biogeochemical processes that control the interannual variability of CO2 fluxes in the equatorial Pacific. In December 1996, chemical and bio-optical instrumentation was installed on the moorings located at 0°, 155°W and 2°, 170°W. The instrumentation included a continuous pCO2 analyzer, three Biospherical irradiance meters, a nitrate analyzer and a PAR sensor on each mooring. The results from the moorings provided the first time series of biogeochemical observations during the 1997-98 ENSO event. Surface water pCO2 data indicate significant interannual variations. The largest variations were associated with the 1997-98 ENSO event, which reached maximum intensity in the winter of 1997-98. The lower air-sea CO2 fluxes during the 1997-98 ENSO period, as well as the drop in primary production and nitrate, were the result of the combined effects of both remotely- and locally-forced physical processes: 1) development of a low-salinity surface cap as part of the formation of the warm pool in the western and central Equatorial Pacific; and 2) deepening of the thermocline by propagating Kelvin waves in the eastern Pacific. Both of these processes serve to reduce pCO2 values towards near-equilibrium values at the height of the warm phase of ENSO. These changes resulted in a lower-than-normal CO2 flux to the atmosphere. The annual average fluxes indicate that strong ENSOs exchange about 0.3-0.4 GtC/yr to the atmosphere; whereas, during non-El Niño years the equatorial Pacific exchanges about 0.9-1.0 GtC/yr to the atmosphere. This difference is enough to account for approximately one-third of the atmospheric anomaly during an El Niño. Our models have suggested that this effect occurs in temperate and polar regions as well. Thus, the ENSO process is the major controlling factor of the interannual variability of the air-sea exchange of CO2 in the oceans. The implication of this study is that El Niño-induced decreases in oceanic upwelling are a major cause of the interannual variability of the air-sea exchange of CO2 in the oceans. During decades dominated by strong El Niño events, such as the present one, more CO2 is retained by the oceans compared with normal decades. Thus, changes in the frequency of El Niño events may have a profound impact on the sea-to-air exchange of CO2. Clearly, the equatorial Pacific is a very important region for studying climate feedbacks of greenhouse warming.
This MBARI-PMEL-AOML collaborative effort over the past two years has been directed towards the design, fabrication, and implementation of the sensors on the Ka'imimoana and on the TAO moorings. Real-time data telemetry utilizes the ARGOS satellite to PMEL and MBARI. At present the group has maintained two mooring in the Equatorial Pacific. Next September, they will outfit a third biogeochemical mooring at Ocean Station P as part of the NOPP Program. These new designs will provide the foundation for the development and maintenance of robust biogeochemical sensors for NOAA’s Ocean Observing Systems.