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    This data set contains sea ice extent at the end of each month, January 1973 - December 1982. The charts are digitized on a 1 degree latitude by 2.5 degree longitude grid. The sea ice was computed for 10 degree longitude "slices" with aerial extent stored in the data set for each of 36 longitude sectors for each month. Ice area is expressed in units of 1000 square kilometers.

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    Week-long samples of airborne particulate matter were obtained at Alert, Northwest Territories, Canada, between 1980 and 1991. The concentrations of 24 particulate constituents have some strong, persistent seasonal variations that depend on the transport from their sources. In order to explore the nature of the cyclical variation of the different processes that give rise to the measured concentrations, the observations were arranged into both a two-way matrix and a three-way data array. For the latter, the three modes consist of chemical constituents, weeks within a year, and years. The two-way bilinear model and a three-way trilinear model were used to fit the data and a new data analysis technique, positive matrix factorization (PMF), has been used to obtain the solutions. PMF utilizes the error estimates of the observations to provide an optimal pointwise scaling data array for weighting, which enables it to handle missing data, a common occurrence in environmental measurements. It can also apply nonnegative constraints to the factors. Five factors have been obtained that reproduce the data quite well for both two-way and three-way analyses. Each factor represents a probable source with a compositional profile and distinctive seasonal variations. Specifically, there are (i) an acid photochemical factor typified by Br, H+, and SO24 and characterized by a concentration maximum around April, or shortly after polar sunrise; (ii) a soil factor representing by Si, Al, and Ca and having its main seasonal maximum in September and October; (iii) an anthropogenic factor dominated by SO24 together with metallic species like Pb, Zn, V, As, Sb, Se, In, etc., peaking from December to April; (iv) a sea salt factor consisting mainly of Cl, Na, and K with maximum concentrations during the period from October to April; and (v) a biogenic factor characterized by methanesulfonate and having a primary maximum at May and a secondary maximum in August. The results obtained by both two-way and three-way PMF analyses are generally consistent with one another. However, there are differences because of additional constraints on the solution imposed by the three-way analysis. The results also help to confirm the hypotheses regarding the origins of the Arctic aerosol.

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    Microparticle analyses were performed on ice samples obtained by core drilling. Data include number of particles in each of 15 size ranges. An additional file contains time scale and annual values of particle concentrations, liquid conductivity, oxygen isotope ratios, and standard deviation of accumulation from 1485 to 1984. An additional file contains time scale and annual values of particle concentrations, liquid conductivity, oxygen isotope ratios, and standard deviation of accumulation from 1485 to 1984.Data are available on one reel of 9-track tape, 1600 bpi. ASCII, unlabeled, copies are available at the cost of reproduction. There are no restrictions on the distribution of these data. References: Thompson, L.G., (1980) Glaciological Investigations of the Tropical Quelccaya Ice Cap, Peru. J. Glac., 25(91), p. 69. Thompson L.G., (1979) Ice Core Studies from Mt. Kenya, Sea Level, Ice and Climatic Change. Iahs Publication No. 131, p. 55. Thompson, L.G., (1977) Microparticles, Ice Sheets and Climate. Ohio State University Institute of Polar Studies. ReportNo. 64, 148 p.; Thompson, L.G., et al. (1975) Climatological Implications, J. Glac., 14(72), p. 433. Thompson, L.G. and E.Mosley-Thompson (1989) One-half millenia of tropical climate variability as recorded in the stratigraphy of the Quelccaya Ice Cap, Peru. AGU, Geophysical Monograph 55, p. 15-31.

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    DMSP F11 monthly averaged sea ice concentration grids in the polar stereographic projection are produced based on daily sea ice concentration grids generated using the NASA Team algorithm. Processing is continuous beginning 3 December 1991, and continues the series begun with F8 monthly averaged data. Although a high degree of correlation exists between F8 and F11 data (Abdalati et al. 1995), regression coefficients (NSIDC 1995) have been applied in deriving F11 daily ice concentrations, which form the basis for this data set. Monthly averaged data files contain ice concentration in percent ranging from 0% to 100%. Then, ice concentrations are delineated using 0%, 5%, 10% and 15% as the minimum concentrations included in the averages (e.g.: a 5% cutoff sets all data values between 1% and 5% to 0%). These four thresholds accommodate as many potential applications as possible. Grids are 8-bit raster images stored in HDF. Data in compressed tar files are distributed via ftp, on sidads.colorado.edu (IP address 128.138.135.20).

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    Annotated citations about pinnipeds (seals, sea lions, and walruses) and cetaceans (whales, dolphins, and porpoises) gathered to assist researchers in formulating and in documenting field work and to give managers and administrators overview of previous work done along with the current status of knowledge. The bibliography includes a species index, area index, and a subject index. In the species index, each entry is followed by letter codes indicating whether the source contains information on abundance, distribution feeding, Beaufort Sea, Chukchi Sea, Bering Sea, Aleutian Ridge, Gulf of Alaska, or a combination. There are also a number of references to articles translated from Russian. The bibliography was published in 1979.

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    Thirty-four drift tracks in the Arctic Ocean pack ice are collected in a unified tabular data format, one file per track. Data are from drifting ships, manned research stations on ice floes (ice islands) and data buoys. Track names are FRAM (ship, 1893 to 1896), NP-01 through NP-20 (Soviet North Pole Stations on ice floes, 1937, 1950, 1954 to 1970), IGY-A and IGY-B (International Geophysical Year buoys, 1957 to 59), T-3 (Fletcher's Ice Island, 1959 to 1970), ARLIS-II (ice island buoy, 1961 to 1965), BTAE (British Transarctic Expedition 1968 to 1969), seven AIDJEX buoys (1972), TEGG (Soviet ship Tegettnoff 1972 to 1973) and St. Anna (Russian ship, 1912 to 1914). Data have been smoothed, interpolated and projected to a two-dimensional coordinate system. Processing applied to original, sporadic data yielded x,y coordinates every two days, and associated velocities (first derivatives) u and v, in centimeters per second. Data are available via anonymous ftp or on various types of magnetic media. Please contact NSIDC User Services for access information.

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    Marine mammal sightings and sighting efforts are included in this data set. Includes position, time, date, weather conditions, number of animals sighted, species sighted, distance and angle to sighting, behavior of animals, water temperature, and comments.

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    Data Type: Boundaries; This dataset depicts native allotments and land inholdings in the Arctic National Wildlife Refuge. This data is an ARC/INFO polygon coverage in an Albers Equal Area projection. These data originated in the U.S. Fish and Wildlife Division of Realty.

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    The database contains bibliographic data, map/chart data, and cruise data, concerning geoscience research in the offshore areas of Western Canada and the Northwestern United States.

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    This data set contains reproductive condition of animals taken periodically.Reference: Briggs, L.J., North Pacific Fur Seal Database, 1988. NWAFC processed report. (In preparation).