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FY 98 Operating Plan for PMEL

Strategic Plan Element: Rebuild Sustainable Fisheries

Objective: Advance Fisheries Predictions

Performance Measure: Improve technology for modeling and predicting survival of larvae and juveniles, and recruitment.

Milestone(Q4): Conduct joint ship, aircraft, and satellite field operations to understand the horizontal scales of primary production in the Bering Sea Greenbelt. (PMEL)
Accomplishments: To establish a basis for mooring site graph ecosystem observations this year, moorings were deployed at standard FOCI sites in the southeastern Bering Sea during February. It was noted that Bering Sea ice had retreated north of mooring 2 (see figure at left) by March. Measurements at this mooring showed a cold, fresh water surface layer and warmer, more saline water at the bottom. In spring, four cruises investigated shelf and slope waters during the period April 14 to June 19. The purpose of these cruises was to examine the spring phytoplankton bloom and its associated physical, chemical, and biological oceanographic processes. During the cruises, moorings were recovered and/or deployed at sites 2, 3, 4, and 6. Scientists conducted biological and physical sampling using net tows and CTD casts at and between mooring sites.

Spring conditions were well documented. Temperatures in the southeastern Bering Sea were warmer than previous years, and there was more storm activity. The level of thermal stratification was less pronounced (the shelf was well mixed to 80m through May) as a result. A recognizable spring phytoplankton bloom had not started by June, and by the end of the season, no spring bloom was evident in either the middle or outer shelf domains. Anomalous conditions (see workshop page) prevailed again this summer with a second year's coccolithophore bloom over the Bering Sea shelf from Bering Strait to the Pribilof Islands. SeaWifs images revealed the presence of aquamarine water (see figure at right) from July through September resulting from light coccolithophore bloom scattering from coccolithophores. Jellyfish were abundant on the outer and middle shelf, but less prevalent in the inner domain. As an indicator of unusual circulation, the NSF Inner Front cruise during June caught offshore euphausiids at the outer ends of their Cape Newenham and Nunivak Island lines. Participants on the July Oshoro Maru cruise reported that the distribution of pollock seems low this year relative to the last four years. They also noted the continuation of the coccolithophore bloom north of St. Paul Island. By mid August shelf water had cooled. By early September storm winds had deepened the mixed layer, and the water was colder than at the same time last year. Sea bird abundance was low, and those sampled were under weight. Birds sampled on the Pribilofs in August were also undersized and there were signs of reproductive failure. The coccolithophore bloom extended from Nunivak Island to the Pribilof Islands and to mooring site 2. Bristol Bay and the coastal regions were not affected. Shelf waters were rich in nutrients, and there were significant zooplankton as opposed to last year when coccolithophores dominated. During mid September the bloom was still prevalent, and project scientists sampled on either side of a front separating typical Bering Sea water from bloom water.

Milestone (Q4): Understand coupled physical-biological interactions affecting Bering Sea/Shelikof Strait walleye pollock survival and recruitment. (PMEL)
Accomplishments: FOCI has developed conceptual models of pollock survival for both Shelikof Strait (see figure below) and the Bering Sea. Because research in Shelikof Strait started seven years before that in the Bering Sea, the Shelikof model is more advanced. However, research this year has increased our understanding of differences in ecosytem dynamics between the two regions. For example, Bering Sea pollock eggs are found higher in the water column and develop more rapidly at cold temperatures than those in Shelikof Strait. Thus Bering Sea pollock eggs are more vulnerable to wind-driven advection but, because of their shorter development time, are less prone to predation. concept model FOCI scientists collaborated with NMFS managers to begin incorporating FOCI's understanding of biophysical factors on recruitment and predation mortality of Shelikof Strait walleye pollock into NMFS operational models. Extensive environmental time series collected and collated by FOCI quantify the dual effects of climate forcing and species interaction for input to a NMFS Alaska Fisheries Science Center stock assessment model. Results from the assessment model provide guidance to the North Pacific Fishery Management Council.
Strategic Plan Element: Advance Short-term Warning and Forecast Services

Objective: Improve Service Communication and Utilization.

Performance Measure: Advanced Emergency Management Technology and Information.

Milestone (Q3): Complete development of prototype operational deep-ocean tsunami detection system. (PMEL)
Accomplishments: Four prototype systems for tsunami early detection and real-time reporting buoysmall.gif (6410 bytes)have been developed and deployed over the past 14 months in the deep ocean, as part of the U.S. National Tsunami Hazard Mitigation Program. The systems utilize bottom pressure recorders (BPRs) capable of detecting and measuring tsunamis with amplitude as small as 1 cm in 6000 m of water, and the data are transmitted by acoustic modem to a surface buoy, which then relays the information to a ground station via satellite telecommunications. Excellent real-time sea level data were received at PMEL during each deployment, proving the concept.   Extended periods of data loss were also experienced, however, and design improvements to increase reliability are currently being implemented.

Strategic Plan Element: Implement Seasonal to Interannual Climate Forecasts

Objective: Maintain and Improve Observing and Data Delivery Systems

Performance Measure: Percent of data from observing systems used in predictions; percent of observing system operational.

Milestone(Q4): Maintain the TAO array portion of the ENSO observing system. The TAO moored array is expected to remain in place for a decade. Each of the the 70 deep ocean moorings will be inspected, serviced, or replaced, as required, approximately twice yearly. (PMEL)
Accomplishments: The Tropical Atmosphere Ocean (TAO) array is a key element of NOAA's recently completed ENSO observing system and nearly 70 deep ocean moorings are maintained across the equatorial Pacific. In FY98, the TAO array, along with other components of the ENSO observing system, were converted to operational status through an act of Congress.

The 1997-98 El Nino has been called "The Climate Event of the Century". It was one of the strongest El Ninos on record, with spectacular impacts on global weather variability and Pacific marine ecosystems. TAO data were used to initialize and validate model forecasts for the 1997-98 event, and to provide essential information at a level of detail never before possible in real-time. Recently developed ENSO forecast models, initialized with satellite and in-situ data from the ENSO observing system, were correct in most cases in predicting that 1997 would be warm and the latter half of 1998 would be cold in the tropical Pacific. This motivated disaster preparedness, mitigation efforts, and other societal responses to developing El Nino conditions on an unprecedented scale. It is expected that, as current cold conditions continue to develop in the tropical Pacific, climate analysis and forecast information will be likewise be valuable for planning purposes, allowing us to translate scientific progress in climate research into societal benefits worldwide.

In order to maintain the moored array, the TAO group participated in 9 different cruises for 260 sea days on both NOAA and Japanese research vessels. A total of 71 moorings were deployed including NextGeneration ATLAS moorings at 16 sites in the array. These new moorings use inductive coupling of subsurface sensors to the surface microprocessor and satellite transmitter, eliminating the separate conducting cable of the older style ATLAS. The simpler mooring design also makes for more efficient assembly, deployment, and recovery. Use of updated electronics makes for higher temporal resolution (10 minutes internally recorded), greater ocean temperature data accuracy, and greater flexibility in adding nonstandard measurements (e.g., salinity, rainfall, radiation). Equatorial velocity measurements and key upper ocean salinity measurements in the western Pacific have also continued and have been used to validate coupled ocean-atmosphere ENSO prediction models. The TAO Project is also working closely with JAMSTEC in their development efforts of Japan's new TRITON buoy. After a period of extensive testing and data comparison, TRITON buoys will replace the ATLAS moorings at 9 sites in the western Pacific.

Strategic Plan Element: Document, Predict, and Assess Decadal-to-Centennial Climate Change

Objective: Understand the Role of the Oceans in Global Change

Performance Measure: Implement in situ technologies for physical and chemical ocean observations.

Milestone(Q4): Maintain and improve an observational system to detect and track the flux of heat and chemicals from the Earth's interior to the deep ocean. (PMEL)
Accomplishments: Within two weeks of the initial event, axial98 image NSF/RIDGE and NOAA/VENTS investigators were able to organize and carry outan opportunistic rapid response to an eruption event detected by the SOSUS acoustic monitoring network. Experience accrued during this rapid response endeavour will prove invaluable in responding to future events in a timely manner.

Beginning at 1200 GMT on 25 January 1998, intense seismicity was detected in the northeast Pacific Ocean using the T-phase Monitoring System developed by NOAA/PMEL to access the U.S. Navy's SOund SUrveillance System (SOSUS).

The initial activity was located on the summit and southern flank of Axial Seamount on the central Juan de Fuca Ridge, near 45 55'N and 130 00'W. The seismic activity lasted twelve days and included over 8,000 earthquakes detected by SOSUS.

Using the Oregon State University research vessel WECOMA, a rapid response effort was conducted from February 9-16. Despite continuous 25 to 40 knot winds, with gusts to 70 knots, and 10 to 18 ft. seas, WECOMA conducted nearly continuous operations, surveying the rift zone in detail, completing 16 vertical CTD casts, and deploying 8 ocean bottom hydrophones (OBH) around the intersection of the south rift zone and the summit caldera; the OBH deployment is the earliest that such instruments have been deployed after a seismic event. After Axial operations were complete, a sound source mooring was deployed at Thompson Seamount and two Tsunami moorings were recovered on the return to Newport.

The CTD/water sampling stations were sufficient to document extensive new venting at Axial Volcano. Very strong hydrothermal signals were detected in the southern portion of the Axial Volcano caldera, as well as at stations to the southwest of the caldera, with hydrothermal discharge from the summit roughly an order of magnitude greater than before the event. Plumes with temperature anomalies approaching 0.20C and intense light attenuation values filled the south end of the caldera, rising at least 200 m above bottom. Plume advection to the southwest was in agreement with past current meter measurements.

Methane and hydrogen concentrations of 600 and 200 nM, respectively, occurred in the plumes at stations near the intersection of the south rift zone with the caldera. Some vertical profiles were dominated by a shallow (1200 to 1400 m) and/or a deep (1400-1550 m) maxima in hydrothermal signals. A cast at the Ashes site revealed a strong plumedigital image with considerable vertical structure, extending from about 1200 m to the seafloor (about 1570 m).

Scanning Electron Microscope (SEM) examination detected glass shards in samples from a hydrothermal plume, and along with other SEM evidence, strongly suggested a lava eruption on the caldera floor, probably centered in the southeast corner of the caldera.

This eruption is the first to occur in the presence of seafloor monitoring instruments, with two Volcanic System Monitors in the caldera, and three temperature sensor/current meter moorings arrayed along the southeast corner of the caldera, exactly at the center of the summit epicenter locations. These instruments, recovered during the VENTS cruises from 30 July to 15 August on the NOAA Ship RONALD H. BROWN, will provide current flow information for calculating heat and chemical fluxes from the caldera.

Milestone (Q4): As part of NOAA's contribution to the National Ocean Partnership Program (NOPP), design, develop and deploy a robust, deep-ocean, air-sea interaction mooring system near the site of Ocean Weather Station PAPA. (PMEL)
Accomplishments: As part of the National Ocean Partnership Program, PMEL has been funded to develop and deploy moorings in the North Pacific in collaboration with the University of Washington/Applied Physics Lab, Scripps Institution of Oceanography, NOAA/NESDIS, and the Naval Research Lab. The first of these moorings will be deployed at Ocean Station PAPA (50N, 145W) from the NOAA Ship Ron Brown on a cruise from Victoria, BC to Seattle from 23 September to October 3, 1998. This mooring will be in place for one year, then recovered and redeployed in late 1999. A second site mooring site, nominally at 35N, 165W, will be occupied in late 1999 with a similarly designed mooring. The two moorings will sample contrasting climatic regimes of the subarctic gyre (PAPA) and subtropical gyre. The PAPA mooring will extend the measurements at this site which began in 1956, first as weather ship measurements (until 1981), then as cruises 3-4 times a year along Line P conducted by the Institute of Ocean Sciences (IOS) in Sydney, BC.

The rationale for this project can be summarized as follows:

  • Substantial interannual to decadal variations in SST occur in the North Pacific associated with El Nino/Southern Oscillation (ENSO) and the Pacific Decadal Oscillation (PDO), but they are not well understood;
  • Anomalous SSTs in the North Pacific are highly correlated with the Pacific North American (PNA) surface atmospheric pressure pattern and with the climate over North America;
  • Variations in North Pacific SSTs are well correlated with various components of the ocean's ecosystem, including plankton and top predators such as salmon;
  • Progress in understanding and ultimately predicting these fluctuations is hampered by lack of systematic time series observations in the upper ocean of the North Pacific.

Much of the PMEL effort during the past year has been involved in the mooring design, equipment acquisition, fabrication, testing, and software development, and interaction with the partners. A robust surface buoy and mooring have been designed for the high latitude deployments with an emphasis on stability and reliability to withstand the forces of typical winter storms. Instrumentation to measure surface meteorology, subsurface temperature, salinity and velocity has been integrated into a high capacity controller mounted in an instrument well on the buoy. Real-time data telemetry will utilize the GOES Data Collection System (DCS) with data retrieval via a 5-m antenna and a Direct Readout Ground Station (DRGS) that was recently acquired at PMEL. A nearby ATOC mooring will communicate with the surface buoy via an acoustic modem, and a compressed file of acoustic travel time information will be transmitted via GOES. In addition, PMEL will deploy an upward looking 153.6 kHz acoustic Doppler current profiler (ADCP) at Station P.

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