FY 2000 Operating Plan for PMEL

Objective 3: Foster well-planned and revitalized coastal Communities that are compatible with the natural environment, minimize the risk from natural hazard and provide access to coastal resources for the Public's use and enjoyment

Performance Measure: Number of improved information management tools developed to assist coastal hazard mitigation

Milestone (Q4): Produce tsunami inundation maps for threatened coastal communities in Alaska, Washington, Oregon, and California. (PMEL-E.Bernard)

Purpose: NOAA bears primary national responsibility for tsunami hazard mitigation, and the purpose of this effort is to reduce the loss of life and property in the Pacific states of Alaska, California, Hawaii, Oregon and Washington.

Efforts: NOAA serves as the lead agency for the U.S. National Tsunami Hazard Mitigation Program, a partnership with the five Pacific state, the U.S. Geological Survey, and the Federal Emergency Management Agency. PMEL's Center for Tsunami Inundation Mapping Efforts (TIME) coordinates and assists the states in the development of inundation maps for coastal communities at risk that are identified and prioritized by the states. This years work was conducted in collaboration with the U. Southern California, the Oregon Graduate Institute, state geoscientists, and state emergency management officials and staff.

Customers: The inundation maps are produced at the request of state emergency management officials and completed maps are delivered to them in the form of electronic data files, imagery, and hard copy. The products derived from these maps, such as evacuation maps, are then delivered to coastal residents in the form of brochures, handouts and other educational materials.

Significance: Inundation maps are an essential emergency management tool and the starting point for pre-disaster hazard assessment, response preparation, recovery planning, and educational programs. Inundation maps provide the primary guidance for the production and publication by the states of evacuation maps which include preferred and alternative routes, safe gathering locations, and important infrastructure information such as hospital, police and fire station locations.

Success: Four maps were completed for California coastal areas near San Diego, Los Angeles/Long Beach, Santa Barbara and San Francisco/San Mateo; these maps also include more than 30 smaller communities. Two maps were completed for the Grays Harbor and Pacific County coasts of Washington, encompassing more than 25 communities. The model development effort and the necessary computational grid was completed for the Kodiak, Alaska region, including three at-risk communities. One map was completed for the Coos Bay, Oregon coastal area. In total, 7 maps were produced, covering more than 7 major population centers and more than 50 smaller coastal communities.

Next Steps: The states will identify and prioritize approximately four coastal areas that require inundation mapping, and PMEL/TIME will assist and coordinate the development of computational grids, the specification of credible "worst-case" scenarios, the numerical simulation of these cases, and the production of the inundation maps.

Milestone (Q4): Recover, isolate, and conduct culturing experiments with microorganisms from deep sea vent systems. (SG, NURP, PMEL-S. Hammond)

Purpose: Deep-sea hydrothermal vents are one of the most ancient and persistent habitats on our planet. Microbial life has evolved over hundreds of millions of years in this environment at the interface of oceans and volcanoes. Only recently have scientists begun to investigate the organisms that live in this ancient environment. Our joint research project between NOAA- PMEL, the University of Washington and other institutions is designed to: 1) recover microbes from a range of different hydrothermal sites in the NE Pacific; 2) use a variety of methods to measure the microbial diversity and community structure at these sites; 3) culture and isolate microbes to understand their metabolism and how they interact with the geochemical environment; 4) investigate the relationship between microbes and geochemistry in diffuse fluids and what this relationship reveals about the subsurface environment, and 5) examine the temporal and spatial variability of this relationship.

Efforts: In 1998, we launched a major effort to establish an observatory at Axial Volcano on the Juan de Fuca Ridge. One of the major goals of this observatory is to understand how microbes interact with submarine volcanoes. Remotely operated vehicles (ROVs) are the best tool for the intricate seafloor operations involved in this research, and the first step was to design and build a ROV-mounted instrument that could sample fluids and particles. PMEL designed and built the first multi-purpose Hydrothermal Fluid and Particle Sampler (HFPS) for scientific ROVs, and we have now used it on three submersibles. This unique sampler allows us to concentrate microbes from large volumes of fluids onto filters for subsequent study. We simultaneously measure temperature and collect fluid for further chemical and microbial analysis. We have now completed 3 years of field work at Axial Volcano and a major sampling program 90km to the north at the Endeavour segment of the Juan de Fuca ridge. In all cases, shipboard and laboratory culturing of microbes has been a major part of the effort.

Customers: Closest to the project, several microbiologists, chemists, biologists and at least 5 graduate students are working directly on samples recovered from our field work using the HFPS and other sampling methods. In a broader context, samples and byproducts are radiating out to other institutions across the country for detailed molecular, biochemical, and biotechnical investigations. Information about our work is presented to the public via the internet through scientific publications and through presentations at national meetings.

Significance: The research we are doing is fundamental to understanding the interplay between life and planetary processes. Microbes are the most ancient and the most abundant and diverse forms of life on the planet, yet we know very little about the extent of microbial habitats, how their metabolism affects and depends upon the chemical environment, and how the potentially huge number of enzymes and biochemical products from unknown organisms could benefit humankind. As we understand more about the extremes of life which microorganisms tolerate and the mechanisms by which they survive, we will broaden our notions about possible habitats on other planets and moons.

Success: This research is generating exciting new results as microbiologists work closely with volcanologists and geochemists to understand the dynamic sub-seafloor biosphere. Each of the microbiological projects described below benefits from close interaction with PMEL investigators with expertise in geology and the chemistry of fluids and minerals. The innovative sampling technology developed for remotely operated vehicles has made much of this microbial work possible. Detailed geological mapping of area affected by volcanic eruptions and time series fluid chemistry data show how the geochemical environment evolves and provide a context for the microbiological measurements.

Although there is mounting evidence that a subsurface biosphere exists within the oceanic crust, little is known about its microbial ecology or geochemistry. Julie Huber's work combines chemical information from the environment (from Dave Butterfield and Richard Feely at PMEL) with microbiological methods to better characterize life within the oceanic crust, using diffuse fluids as a window into the subsurface biosphere. By using a variety of methods, we can better understand the interactions between microbes and hydrothermal fluids, as well as examine subsurface biotopes and how these biotopes may be related to one another, if at all. One of the microbes now in culture produces copious amounts of muco-polysaccharide slime, which may be involved in forming biofilms on mineral surfaces.

Jon Kaye's research concerns the ecology of salt- and metal-tolerant microbes over a wide range of temperatures. The phylogeny, physiology and enumeration of these microorganisms in conjunction with chemical measurements aids in the development a comprehensive ecosystem model relating biological, geochemical and hydrothermal processes in vent and subseafloor environments.

Matt Schrenk's work investigates the microbial ecology of hydrothermal vent chimneys by mapping the occurence and diversity of microorganisms in relation to their environment. He does this by observing the microbes and their rock "homes" directly with microscopes, but also with indirect biochemical and geochemical methods which allow him to characterize the environment. Matt has done a portion of this work in Richard Feely's lab, using the Scanning Electron Microscope.

Biological nitrogen fixation the reduction of dinitrogen gas to ammonium may be an important source of nitrogen for hydrothermal vent communities, which are often nitrogen limited. In order to characterize the nitrogen-fixing communities from both a nitrogen limited environment (Axial Volcano) and a nitrogen rich environment (Endeavour Segment), Mausmi Mehta's work uses molecular tools that can detect and distinguish between nitrogenase-possessing organisms and nitrogenase-expressing organisms.

Recent References

Next Steps: We will continue to develop the seafloor observatory at Axial Volcano to learn how vent environments change over time. Detailed chemical and microbiological analysis of samples is ongoing. A new development is the proposed installation of seafloor sampling instrumentation that can be controlled via acoustic modem-satellite link from our laboratory on shore to collect fluid and particle samples on command and deliver continuous information about the vent environment and its response to volcanic or tectonic disturbances in the area.

GOAL: BUILD SUSTAINABLE FISHERIES

Objective 1: Eliminate and prevent overfishing and overcapitalization.

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

Milestone (Q3): Develop and improve methods for gathering and using information relating to fisheries management. (PMEL-P.Stabeno)

Purpose: The Bering Sea produces nearly half the nation's seafood and is critical habitat for many marine mammals and seabirds, including the endangered Steller sea lion. Modern fisheries managers increasingly rely on results from ecosystem research as well as survey-based approaches that have been used in the past. The transfer of information from research to management is critical to optimize balance between conservation and use of natural marine resources.

Efforts: Fisheries-Oceanography Coordinated Investigations (FOCI,) works on three fronts to develop and improve gathering and distribution of information relating to fisheries management.

The first is improved real-time data collection, processing and distribution. For the sixth consecutive year, FOCI maintained a key biophysical mooring on the southeastern Bering Sea shelf to document physical, chemical, and biological variability. This mooring provides the only long-term measurements of ocean currents, temperature, salinity, nutrients, and primary production in the Bering Sea. As possible, data from this and other FOCI biophysical moorings are transmitted in near-real time via satellite, quickly processed, and distributed through the Worldwide Web. Interpretations of these measurements enable scientists to elucidate relationships between oceanographic conditions and the biological environment.

Second, improvements were made to the Bering Sea and North Pacific Ocean Theme Page, an information resource for the scientific investigation of the biology, oceanography, meteorology and ecology of the Bering Sea and North Pacific Ocean. It provides a forum for presenting and discussing new ideas, plans and research results. One of its elements is the Bering Sea Ecosystem Biophysical Metadatabase, an interactive research tool for ecosystem investigation and education.

Third, FOCI assembled a scientific panel to synthesize information on the physical and biological environments of the Gulf of Alaska, Aleutian Islands, and Bering Sea for transmission to management.

Customers: FOCI disseminates information to a wide variety of customers: students, scientists, fishermen, educators, and managers. Principal among these is the North Pacific Fishery Management Council, the body responsible for governing the regional fishing industry. FOCI communicates to the council through the National Marine Fisheries Service's stock assessment and stock forecast documents.

Significance: FOCI's biophysical mooring at site 2 in the southeastern Bering Sea has been deployed annually since 1995. This is the longest, near-continuous stream of biophysical oceanographic data from any location in the Bering Sea. Long-term time series like this are crucial for describing ecosystem variability and recognizing ecosystem change.

The Bering Sea and North Pacific Ocean Theme Page is an information clearinghouse designed to serve a wide range of users and to be the leading reference on its subject on the Worldwide Web. Its metadatabase is the only catalog of Bering Sea biophysical data and was created in response to the National Academy of Science's note of the lack of such a catalog.

Several years ago in the wake of the closure of the New England fishery, the North Pacific Management Council adopted a holistic, ecosystem approach to fishery management. FOCI is one of the chief programs to supply scientific information to the council. Annual syntheses and updates of information relating climate to ecosystem change in the Gulf of Alaska, Aleutian Islands, and Bering Sea are the basis for the Ecosystems Considerations chapter of the "Stock Assessment and Fishery Evaluation" report published for the North Pacific Fishery Management Council.

Success: Information from FOCI's Bering Sea biophysical moorings was a basis for the lead article in Dynamics of the Bering Sea, a summary of physical, chemical, and biological characteristics, and a synopsis of research. This book supercedes previous volumes as the world's leading reference for Bering Sea ecosystem research and poses significant questions about effects of commercial fishing on the ecosystem. Biophysical mooring information is also critical to the planned special edition of Tropical Studies in Oceanography on the ecosystem of the southeastern Bering Sea.

Users accessed the Bering Sea and North Pacific Ocean Theme Page over three-quarters of a million times in the past year. The site was expanded to include improved communications resources such as a chat room for information exchange and a subscription service to news postings. Data references from Russia were added to the metadatabase that is presently serving about 3000 users a month. Total metadatabase content is now about 1500 records.

FOCI's scientific panel contributed to "Ecosystem Considerations for 2000" a chapter of the 2000 Stock Assessment and Fishery Evaluation report. Topics analyzed and presented for education of the North Pacific Fishery Management Council included interannual variability of atmospheric forcing, seasonal rainfall at Kodiak, wind mixing in the western Gulf of Alaska, and, for the eastern Bering Sea shelf, ice extent and timing, water-column temperature cycling, timing of the last spring storm, and cross-shelf advection.

Next Steps: Plans are underway through the proposal process to continue the Bering Sea biophysical moorings during 2001 and 2002. FOCI has also requested funds to continue to expand the theme page and metadatabase. The focus this year for the metadatabase will be inclusion of more Japanese data, and personnel will attend the annual PICES meeting in Hakodate, Japan, during October to further this cause. FOCI's scientific panel is reviewing the year's developments in preparation for the 2001 ecosystem discussion for the North Pacific Fishery Management Council.

Milestone (Q4): Develop and deploy a bio-physical mooring in the North Pacific Ocean to assess the oceanographic and atmospheric impacts of long-term climate and oceanographic variability on commercially important fish stocks. (PMEL-P.Stabeno)

Purpose: The northern oceans are important contributors to world production of commercial fish and shellfish. The Bering Sea, an extension of the North Pacific Ocean, alone produces nearly half our nation's seafood and is critical habitat for many marine mammals and seabirds, including the endangered Steller sea lion. During the past ten years, scientific research has revealed decadal- and longer-scale North Pacific Ocean climate regimes, such as the Pacific Decadal Oscillation (PDO), that influence the marine ecosystems of the region. Because scientists lack long-term, coordinated measurements of physical and biological variables, we do not yet understand the linkages and mechanisms between climate forcing and ecosystem response. For example, at a critical time last year, scientists could not state whether a decline in Steller sea lion abundance was due to anthropogenic influences of commercial fishing, natural variation related to climate, or a combination of the two. This lack of information contributed to an ongoing commercial fishing crisis in the Bering Sea and Gulf of Alaska. A network of biophysical moorings, such as the one described in this milestone, was intended to provide local information on a Pacific basin-wide scale to help scientists understand climate change and enable fishery managers to optimize balance between conservation and use of natural marine resources.

Efforts: Fisheries-Oceanography Coordinated Investigations (PMEL/FOCI,) has pioneered development of biophysical platforms that can monitor the harsh Bering Sea and North Pacific Ocean environments on a year-round basis. The utility of these platforms has been proven in the Bering Sea since 1996. Planned expansion of the monitoring program from the Bering Sea to the North Pacific Ocean under the Fisheries and the Environment Program (FATE) was not funded this fiscal year. Instead, additional development and deployment activities were focused on the Bering Sea. FOCI continued to maintain a key biophysical mooring at site 2 on the southeastern Bering Sea shelf. An in situ nitrate meter was included on the biophysical platform this year. Information from the meter, when interpreted with other measurements, will shed light on the processes that transfer nutrients from the basin to the productive shelf. Recent enhancements to FOCI's biophysical platforms will be applied to future deployments planned for the North Pacific Ocean.

Customers: FOCI disseminates information to a wide variety of customers, including scientists and fishery managers. The envisioned network of biophysical platforms in the North Pacific Ocean was to provide the climate community with data on the spatial and temporal nature of North Pacific climate changes and their affect on ocean physics and lower-trophic biology. Although information from site 2 allows some insight into North Pacific climate change, FOCI still intends to serve its customers with information from a wider network of platforms. Penultimately, FOCI products lend guidance to the North Pacific Fishery Management Council (NPFMC), the body responsible for governing the regional fishing industry. Several years ago, in the wake of the closure of the New England fishery, the council adopted a holistic, ecosystem approach to fishery management. FOCI is one of the chief programs to supply ecosystem information to the council.

Significance: Over the last few years, it has become evident that the climate of the North Pacific Ocean is changing. Coastal waters have cooled from California to the Bering Sea. West coast salmon abundance is growing. Sardines have returned to the California coast. Jellyfish are on the rise in the Bering Sea, and vast blooms of coccolithophores have occurred on its shelf. Throughout this time of change, FOCI's biophysical platform at site 2 in the southeastern Bering Sea has documented variability of ocean currents, temperature, salinity, nutrients, and primary production, bracketing a probable change in the PDO that occurred in 1997. The time series from this site is one of just a few in the northern sector of the Pacific that can be used to increase understanding of the mechanisms and effects of climate change.

Success: Data collection by FOCI biophysical platforms at site 2 has been successful for six years, providing a nearly continuous data set. Using this information, FOCI and other scientists are formulating new hypotheses of ecosystem dynamics for the southeastern Bering Sea shelf. These form the basis for the synthesis phase of Southeast Bering Sea Carrying Capacity (SEBSCC), a NOAA Coastal Ocean Program regional ecosystem study. FOCI biophysical mooring information is also critical to a special edition of Topical Studies in Oceanography, now in production, on the ecosystem of the southeastern Bering Sea. Information from biophysical platforms also contributes to annual syntheses and updates relating climate to ecosystem change in the Gulf of Alaska, Aleutian Islands, and Bering Sea. These syntheses are incorporated into "Ecosystem Considerations for 2001". This chapter is part of NMFS's 2001 Stock Assessment and Fishery Evaluation report prepared for the NPFMC.

Next Steps: FOCI plans to augment the biological instrumentation carried by its biophysical platforms. The next addition will be an acoustic zooplankton counter. This will be installed on a planned FOCI platform in the northern Gulf of Alaska with funding through U.S. GLOBEC Funds from SEBSCC will maintain the Bering Sea biophysical mooring at site 2 through 2001. FOCI also has requested funds to continue occupation of this site after 2001 and to expand the network of biophysical platforms into the North Pacific Ocean through the FATE initiative.

GOAL: ADVANCE SHORT-TERM WARNING AND FORECAST SERVICES

Objective 3: Enhance observations and prediction

Milestone (Q4): Deploy a network of prototype real-time, deep-ocean, tsunami detection moorings. (PMEL-E.Bernard)

Purpose: PMEL's Deep-ocean Assessment and Reporting of Tsunamis (DART) Project is an effort to directly measure tsunami energy propagating towards coastal communities so as to increase the speed and accuracy of tsunami warnings and to reduce costly false alarms that undermine the credibility of the warning system.

Efforts: The early recognition that improvements in the timeliness and accuracy of tsunami warnings were possible led PMEL scientists to conceive a plan to measure tsunami wave energy in the open ocean rather than at shoreside tide gauges. By making the measurements in deep water, far from shore, increased warning time was possible and improved accuracy resulted because the wave energy was not being influenced from shallow water and shore-based effects. An added benefit is that observations can also be used as a basis for sounding the "all clear" following an event, allowing the deployment of rescue personnel and the return of affected people to their homes and businesses.

PMEL scientists and engineers have developed the DART system over the past five years. Researchers have developed software that allows a seafloor-mounted pressure recorder to isolate tsunami energy frequencies from the total ocean wave energy spectrum. PMEL engineers then developed and improved acoustic modem technology such that a sensor package located on the seafloor can transmit data acoustically through the water column to a receiver mounted on a robust surface buoy. The buoy, in turn, sends this data via satellite to the two NOAA tsunami warning centers and to PMEL.

Deployments of prototype DART systems began in 1998. In 2000, a 3-mooring system designed to provide early warning to west coast states and Hawaii from an earthquake in the Alaska Aleutian Subduction Zone was established. A fourth mooring is located off the Oregon coast.

Customers: Primary users of DART data are NOAA's Pacific Tsunami Warning Center and the West Coast and Alaska Tsunami Warning Center. Secondary users include the tsunami research and hazard mitigation community, including state and local emergency managers, and academic institutions. Ultimately, the most important customers are the people who live and work in coastal communities at risk from tsunamis.

Additional customers may include individuals conducting research on ocean tides and other low frequency sea level phenomena. Data is disseminated to customers via the World Wide Web. NOAA's tsunami warning centers receive DART data directly via satellite downlink.

Significance: The DART Project is an effort of the U.S. National Tsunami Hazard Mitigation Program to develop early tsunami detection and real-time reporting capability. These data enable a more direct and rapid assessment of the tsunami hazard and, when coupled with model forecasting tools, provide 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 occurring in the Alaska Aleutian Subduction Zone. DART stations between this zone and Hawaii provide tsunami measurements within this critical time frame so that potentially destructive tsunamis will be more reliably identified, thus reducing the number of unnecessary evacuations due to false alarms. 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 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. Continued offshore tsunami monitoring provides important guidance for decision-makers, who must evaluate 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."

Success: Having successfully survived the 1999-2000 winter storm season on station in the North Pacific, mooring technology developed at PMEL has been shown to be sufficiently robust and reliable to withstand the rigors of a long, harsh deployment.

Improvements in the acoustic modem data link that were implemented on the D130 (42.89N, 130.92W) system prototype have greatly reduced problems inherent in prior systems. Because of this prototype's performance, receivers were upgraded on other DART moorings deployed south of the Aleutian Islands in August 2000. All four currently deployed DART systems are returning data at a rate of 95% or better.

Next Steps: Establishment of a planned six-station DART network designed to provide early detection and measurement of tsunamis generated in the primary source regions that threaten U.S. coastal communities will be completed in 2001. In August, a system will be deployed along the Cascadia Subduction Zone off the Washington Coast. The network will be completed with the deployment of a system in the Equatorial Pacific along the South American Subduction Zone in September.

Subject: Technology for Physical and chemical ocean observations

Milestone (Q3): Deploy hydrophone arrays in selected regions not covered by SOSUS. (PMEL-S.Hammond)

Purpose: Dual-use of the U.S. Navy's SOund SUrveillance System (SOSUS) by NOAA has led to fundamental discoveries into seafloor volcanism, oceanic seismicity, the distribution and behavior of large marine mammals, and forms an invaluable data base of the increase in anthropogenic noise in the sea. The original deployment of SOSUS was based on military considerations only and does not cover all areas of the global ocean. PMEL has developed a new portable technology to allow the collection of calibrated digital acoustics data anywhere in the ocean at relatively low cost. These autonomous hydrophone systems are being deployed at key areas around the world ocean to address specific scientific questions at sites not covered by SOSUS.

Efforts: PMEL has developed low-cost autonomous hydrophone recorders using in- house engineering expertise and commercial off-the shelf (COTS) hardware. The current generation of the instrument is capable of recording 32 gigabytes of data which allows, for example, recording at 1,000 Hz continuously for up to 14 months. Hydrophone arrays have been deployed in the eastern equatorial Pacific (since May, 1996) in conjunction with the TAO/TRITON array, in the North Atlantic between 15N and 35N (since March, 1999) funded by NSF, and in the Gulf of Alaska (since October, 1999) to address questions of blue whale migration.

Customers: Seismic data from the equatorial Pacific hydrophone array provided research targets for a recent NSF-sponsored field expedition and provides volcano monitoring and seismicity maps for the entire scientific community. The Atlantic array was funded by NSF to explore the general seismicity of that region. The Gulf of Alaska array provides data critical to NMFS, the International Whaling Commission, and the U.S. Navy on the distribution of large whales in the open ocean. Requests for data have been received from DoD, the Comprehensive Test Ban Treaty Organization, and DoE, as well as several university researchers

Significance: Underwater acoustics provides the only viable means of monitoring volcanism, seismicity, and marine mammal distribution in the open ocean.

Success: Numerous peer-reviewed articles have been published or are in press. Several other agencies and international groups have requested collaborative experiments

Next Steps: OAR and NMFS have submitted an FY02 budget initiative to address the issue of noise pollution in the marine environment. The global monitoring aspect of this effort will depend largely on the large-scale deployment of PMEL autonomous hydrophones. Partnering with other researchers continues to address multiple questions in marine seismics and biology.

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.

Milestone (Q3): Report the major findings from the 1997 ACE II field campaign that characterized the aerosol radiative forcing over the North Atlantic. (ERL, OGP, PMEL-T. Bates)

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 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 42 peer-reviewed research articles that were published in a special issue of Tellus in April 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 four 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 the ACE-Asia that will focus on the region downwind of the rapidly increasing pollution sources in eastern Asia. The intercontinental transport of Asian aerosols can affect both regional climate and air quality. NOAA scientists will participate in ACE-Asia aboard the R/V Ronald H. Brown in March-April 2001.

Performance Measure: Results of 90% of the research activities are to be cited in the year-2000 IPCC Third Assessment of Climate Change.

Subject: Track climatically-important oceanic variability

Milestone (Q2): Deploy chemical sensors aboard the NOAA Ship Ka'imimoana along equatorial Pacific cruise tracklines in the region of the TAO Array. (ERL, OGP, PMEL-R.Feely)

Purpose: The primary objective of NOAA's Global Carbon Cycling Program (GCCP) is to quantitatively assess the fate of CO₂ in the atmosphere and oceans. The CO₂ Program at the Pacific Marine Environmental Laboratory in Seattle, Washington, conducts research on the sources and sinks of carbon dioxide in the oceans. Atmospheric and oceanic carbon dioxide data are collected on cruises onboard selected NOAA vessels and from sensors installed on TAO array moorings. The TAO Array is maintained by the NOAA Ship KA'IMIMOANA.

Efforts: In a collaborative project sponsored by the NOAA Office of Global Programs, PMEL and AOML scientists have developed and deployed developed a new temperature-controlled, automated underway pCO₂ system for the KA'IMIMOANA to obtain a better understanding of the physical and chemical processes that control the interannual variability of CO₂ fluxes in the equatorial Pacific.

Significance: The pCO₂ measurements are made with a differential, non-dispersive, infrared Li CorTManalyzer. The new system was developed as a joint project between the PMEL and AOML CO₂ groups and deployed on the KA'IMIMOANA in fall of 1996. To date, we have sucessfully used the pCO₂ system on approximately 40 cruises of the KA'IMIMOANA in the Equatorial Pacific. The analytical precision of the system is approximately 0.3 - 0.4 ppm for seawater and for air.

Customers: High quality data are required to reduce uncertainty in global carbon prediction models. Modeling studies employing these data enhance our understanding of the ocean's role in the global carbon cycle and the important feedback mechanisms that affect future climate changes. Improved predictions will provide decision-makers quantitative information necessary for making critical economic decisions regarding greenhouse gases.

Success: The results from these cruises provided the first detailed observations of the regional variability of pCO₂ during the 1997-98 ENSO event. The data show the large interannual effects of El-Niño on CO₂ exchange in the equatorial Pacific. From the normal conditions of 1996 to the mature El Niño period during the1997-98 event, the average CO₂ fluxes from 10°S to 10°N and 80°W to 135°E decreased from approximately 20 to 0.3 mol Cm-2yr-1. The high CO₂ fluxes in 1996 were due to increased surface water pCO₂ values and higher winds. The Equatorial Undercurrent was much closer to the surface in 1995-96, and supplied the higher pCO₂ found in surface waters.
The lower fluxes during the 1997-98 El Niño were primarily the result of the weaker winds and the transport of the CO₂-depleted warm pool into the central and eastern equatorial Pacific. We estimate that for the 1-year period of 1996 approximately 0.9±0.6 PgC as CO₂ was released to the atmosphere. In sharp contrast, for the 1-year period from the spring of 1997 to the spring of 1998, the CO₂ flux to the atmosphere was approximately 0.2±0.14 PgC over the same region. Thus, the amount of CO₂ retained in the equatorial oceans during the 1997-98 El Niño period (i.e., 0.7±0.4 PgCyr-1) was slightly higher than during the severe El Niño of 1982-83 (~0.6 PgCyr-1). During the decade of the 1990s, which was dominated by strong and prolonged ENSO events, approximately 2-3 PgC more CO₂ was retained by the equatorial oceans compared with normal decades.

Next Steps: This PMEL-AOML collaborative effort over the past three years has been directed towards the design, fabrication, and implementation of the underway pCO₂ system on the KA'IMIMOANA. Our group has recently developed and deployed a similar automated system for the NOAA Ship RON BROWN. These new systems will provide the basis for the development of automated sensors for the NOAA Fleet.