IMMU v.5no.3 19602 C-CAP, from page 1 guidelines development. The C-CAP regional guidelines document is being published as NOAA Technical Report NMFS 123 and contains sources and procedures for data acquisition, processing, and presentation. The protocol's land cover classification scheme is dynamic and will be improved upon in future editions as it becomes refined through research and input from regional projects. Nationwide acceptance of the protocol will allow comparable analyses to be conducted and land cover products to be generated, regardless of which organization funds or performs the study. Regional Analysis Coastal regions are identified as candidates for periodic monitoring based upon the frequency of environmental changes. An agreement is normally made between C-CAP, local researchers, and coastal managers, to perform the analyses in accordance with the regional guidelines document and to provide the results to C-CAP. In some instances the analyses are performed by ORNL with cooperation from local experts for field verification. To monitor functional status and change in these critical habitats, C-CAP employs satellite images and aerial pho EARTH SYSTEM MONITOR tography to cover large coastal areas of interest. When feasible, Landsat satellite Thematic Mapper sensor scenes for a region, observed during clear atmospheric and dry ground conditions, are purchased from the Earth Observation Satellite Company (EOSAT) for approximately the same time of year for two different years. Sensor scenes are then analyzed to determine land cover and classified according to the C-CAP protocol. A third result of the analyses, land cover change, is the difference data set between the different years. Land cover data sets derived from Thematic Mapper data are binary raster. Each suite has a unique size because of the number of Landsat scenes used and because the amount of truncation done during analysis varies by region. Vertical aerial color photographs of metric quality are taken during acceptable weather conditions from fixed wing aircraft to determine location and areal extent of submersed rooted vegetation (SRV). These are photointerpreted, classified, and digitized into vector data sets. In many cases, the goal is a suite of three data sets, two time periods, and a change detection (Ferguson, et al., 1993). Fourteen land cover analyses and/or habitat monitoring projects (Figure 2), jointly sponsored by C-CAP and other federal, state, local, or academic institu- continued on page 7 ▲ Figure 2. Locations of current land cover analyses and habitat monitoring projects, which are being jointly sponsored by C-CAP and other Federal, state, local, and academic institutions. March 1995 EARTH SYSTEM MONITOR The Earth System Monitor (ISSN 10682678) is published quarterly by the NOAA Environmental Information Services office. Questions, comments, or suggestions for articles should be directed to the Editor, Richard J. Abram. Requests for subscriptions and changes of address should be directed to the Assistant Editor, Nancy O'Donnell. The mailing address for the Earth System Monitor is: Environmental Information Services NOAA/NESDIS E/EI Universal Building, Room 506 1825 Connecticut Avenue, NW Washington, DC 20235 EDITOR Richard J. Abram Telephone: 202-606-4561 Fax: 202-606-4586 E-mail: rabram@nodc.noaa.gov ASSOCIATE EDITOR Sheri Phillips Telephone: 202-606-4539 Fax: 202-606-4586 E-mail: sphillips@nodc.noaa.gov ASSISTANT EDITOR Nancy O'Donnell Telephone: 202-606-4561 Fax: 202-606-4586 E-mail: nodonnell@nodc.noaa.gov DISCLAIMER Mention in the Earth System Monitor of commercial companies or commercial products does not constitute an endorsement or recommendation by the National Oceanic and Atmospheric Administration or the U.S. Department of Commerce. Use for publicity or advertising purposes of information published in the Earth System Monitor concerning proprietary products or the tests of such products is not authorized. UNIVERSITY OF MICHIGAN LIBRARIES Workshop produces plan to use paleoenvironmental research in climate variability studies Dr. Jonathan Overpeck, head of NGDC's Paleoclimatology Group, co-convened a joint International Geosphere Biosphere Programme - World Climate Research Programme (IGBP-WCRP) sponsored workshop entitled "A Paleoclimatic Perspective on Climate Variability and Predictability". The workshop, held in Venice, Italy, on November 16-20, 1994, brought together the world's leading paleoclimatologists and climate physicists to generate an explicit interdisciplinary workplan for using paleoenvironmental research to develop a complete understanding of interannual to century-scale climate variability. Simulation of climate variability with predictive models was also examined. This understanding is not possible using the short satellite and instrumental record alone. The workshop served as a basis for focussing the international IGBPWCRP research community on meeting climate prediction goals that are central to NOAA. Dr. Overpeck also participated in an Executive Committee meeting of the International Geosphere Biosphere Programme/Past Global Change Core (IGBP/PAGES) Project. Dr. Overpeck, elected to this committee earlier this year, helped guide the implementation of the large international IGBP/PAGES research program. In particular, he aided in the coordination of paleoenvironmental data management efforts around the world. The World Data Center-A for Paleoclimatology at NGDC is the data management coordination center for IGBP/PAGES. NCDC Supports Florida Coastal The National Climatic Data Center provided several CD-ROM products to support the Florida Oceanographic Society Coastal Science Center. The mission of the society is to increase the knowledge and understanding of Florida's marine resources through education, public awareness, and the support of scientific research. The Coastal Science Center is being developed on Hutchinson Island along Florida's east coast. The center will include a library, auditorium, conference center, aquariums, and research facilities. The center will also operate and maintain two coastal weather News briefs stations with "real time” weather and sea state conditions available. NCDC provided copies of the U.S. Navy Marine Climatic Atlas of the World Volume 1.0, the International Station Meteorological Climate Summary Version 2.0, and several additional CD-ROMs as part of a climatology package which will be on display at the center. NGDC receives new data from the international community Professor Meiqing Gao, from the Institute of Geophysics, Academia Sinica, Beijing, China, delivered 56 years of geomagnetic hourly data from the Sheshan Magnetic Observatory to NGDC. The data will be placed on a one-off CD-ROM which will be handcarried back to China by Professor Gao. The data will be included on a planned CD-ROM of geomagnetic hourly values to be produced in 1995. NGDC has also received annual mean values from four geomagnetic observatories in Vietnam. These data are the first received from Vietnam at NGDC (for Solid Earth Geophysics) in many years. The data were sent in response to the Solid Earth Report-52, A Report on Geomagnetic Observatories and Observations, 1994, and represent the fulfillment of several months of work in establishing contacts with the Institute of Geophysics in Vietnam. In addition, a data exchange agreement has been established between NGDC and the Instituto de Astronomia y Geodesia, Universidad Complutense de Madrid, Spain. The Institute forwarded gravity data from the Mediterranean Sea in response to a letter from NGDC that opened discussions in August. They also have offered to forward additional gravimetric data from Spain and Portugal. 38th conference on Great Lakes research scheduled The International Association for Great Lakes Research (IAGLR) announces the 38th Annual Conference on Great Lakes Research, to be held at the Kellogg Center on the campus of Michigan State University from May 28 through June 1, 1995. The purpose of the conference is to exchange information applicable to the understanding of large lakes of the world, and to the human societies surrounding them. To date, at least 25 special symposia are scheduled. Topics include such issues as physical dynamics, causality and risk assessment, atmospheric processes, global change records in lakes, food chain transfers, remedial action plans, combined sewer overflow, groundwater and lake interactions, wetlands research, large lakes of the world, contaminated sediments, toxicology, and exotic species. Preliminary program details will be published in the IAGLR Lakes Letter newsletter released in April. Registration for the conference will begin on Sunday, May 28, 1995; preregistration is encouraged. Registration will be followed by four days of technical sessions, poster presentations, and exhibits. For additional information on this conference, please contact: Communications hub for ARCSS The National Snow and Ice Data Center (NSIDC) is developing a bulletin board for the Arctic System Science (ARCSS) community at the ARCSS Data Coordination Center. A Home Page will be accessible using Mosaic or similar software. This site will also function as a listserver, allowing access by electronic mail as well. Using Mosaic, users will be able to browse text, post and read messages, view the ARCSS Data Catalogue, and link to other information sources at NSIDC. Users without access to Mosaic can email to the listserver, receive a list of message headers, and send e-mail back to receive text of interest. For more information, please contact Matt Cross at 303-392-5532 or through the Internet at: cross@kryos.colorado.edu NODC archives shipboard ADCP data Acoustic Doppler Current Profiler data provides information on structure of the upper ocean Patrick Caldwell National Oceanographic Data Center NOAA/NESDIS For the past decade, acoustic Doppler current profilers (ADCPs) have become steadily more common aboard the University National Oceanographic Laboratory System (UNOLS), NOAA, and U.S. Navy fleets. During the late 1980s, the data quality was limited by lack of continuous Global Positioning System (GPS) coverage and uncertainties in the ship's heading information. For the past several years, however, the quality has improved significantly due to the 24-hour GPS coverage, differential gps techniques, and the advent of GPS heading sensors. With reliable heading and navigation data, absolute currents in the upper ocean are determined. The data provide fine resolution in time (~5 minutes), depth (~10 m), and horizontal distance (~2 km) throughout the duration of a cruise. The accumulating database allows a fresh view of upper ocean velocity structure on a variety of temporal and spatial scales. The National Oceanographic Data Center (NODC) has been working for several years on a management scheme for this important new data set and is now ready to share the plan with the scientific community and solicit contributions to the shipboard ADCP archive. Methodology of data acquisition The hull-mounted ADCP estimates horizontal and vertical velocity as a function of depth by using the Doppler effect to measure the radial relative velocity between the instrument and scatterers in the ocean (Figure 1). Three acoustic beams in different directions are the minimal requirement for measuring the three velocity components. A Mr. Patrick Caldwell E-mail: caldwell@soest.hawaii.edu fourth beam adds redundancy and an error estimate. The ADCP transmits a ping from each transducer element roughly once per second. The echo arrives back at the instrument over an extended period, with echoes from shallow depths arriving sooner than ones from greater ranges. Profiles are produced by rangegating the echo signal, which means the echo is broken into successive segments called depth bins which correspond to successively deeper depth ranges. The operator configures the length of each depth bin and the transmit pulse, which determines the degree of averaging in the vertical, depending on whether one is interested more in vertical resolution or profile penetration. The noisy velocity estimates from each ping are vector-averaged into 1- to 10-minute ensembles. The relative velocities are rotated from the transducer's to the earth's reference frame using the ship's gyrocompass. Finally, relative velocities and various ancillary parameters are stored on the ship using a data acquisition system (DAS) which also optionally records navigation information, such as provided by the GPS. Specifics of the instrument capabilities and configuration options are well documented (RDI, 1989). Routine processing, quality control, and calibration are performed at the host institution. Standard checks include detecting and correcting time errors, applying transducer-level temperatures and salinities to obtain a better estimate of the sound speed for the velocity calculation, editing out bad bins or profiles that have been contaminated by interference with the bottom or some other physical object such as a hydro wire, and verifying the quality of the gyrocompass and the navigation data. The final gyrocompass estimates of ship heading and the navigation information are the primary sources for calibrating the ADCP's relative current velocities. Typically, one is correcting for a "angle" error due to misalignment of the transducer relative to the ship's hull and an "amplitude" component related mostly to minor imperfections of the transducer geometry. Relative current velocity errors caused by these components are orthogonal; the angle errors lead to uncertainties of the athwartships velocity component while the amplitude error introduces uncertainties along the ship track. The navigation calculation is performed once calibration is complete. Absolute currents over a fixed depth range (reference layer) are obtained by subtracting the average of the ship ve |