Monthly average polar sea-ice concentrationEntry ID: USGS_DDS-27
Abstract: The purpose of this data set is to provide paleoclimate researchers with a tool for estimating the average seasonal variation in sea-ice concentration in the
modern polar oceans and for estimating the modern monthly sea-ice concentration at any given polar oceanic location. It is expected that these data will be compared with paleoclimate data derived from geological proxy measures such as faunal ... census analyses and stable-isotope analyses. The results can then be used to constrain general circulation models of climate change.
This data set represents the results of calculations carried out on sea-ice-concentration data from the SMMR and SSM/I instruments. The original
data were obtained from the National Snow and Ice Data Center (NSIDC). The data set also contains the source code of the programs that made the calculations.
The objective was to derive monthly averages for the whole 13.25-year series (1978-1991) and to derive a composite series of monthly averages representing
the variation of an average year. The resulting file set contains monthly images for each of the polar regions for each year, yielding 160 files for each
pole, and composite monthly averages in which the years are combined, yielding 12 more files. Averaging the images in this way tends to reduce the number of
grid cells that lack valid data; the composite averages are designed to suppress interannual variability.
Also included in the data set are programs that can retrieve seasonal ice-concentration profiles at user-specified locations. These nongraphical
data retrieval programs are provided in versions for UNIX, extended DOS, and Macintosh computers. Graphical browse utilities are included for the same computing platforms but require more sophisticated display systems.
The data contained in this data set are derived from the Scanning Multichannel
Microwave Radiometer (SMMR) and Special Sensor Microwave/ Imager (SSM/I) data
produced by the National Snow and Ice Data Center (NSIDC) at the University of
Colorado in cooperation with the U.S. National Aeronautics and Space
Administration (NASA) and the U.S. National Oceanic and Atmospheric
Administration (NOAA). The basic data come from satellites of the U.S. Air
Force Defense Meteorological Satellite Program. NSIDC distributes three
collections of sea- ice-concentration grids on CD-ROM: data from the Nimbus-7
SMMR (October 25, 1978 through August 20, 1987) are provided on volume 7 of the
SMMR Polar Data series (NASA, 1992); data from the SSM/I are provided on two
separate volumes, covering the periods from July 9 of 1987 to December 31 of
1989, and from January 1 of 1990 through December 31 of 1991, respectively. The
NASATEAM data from revision 2 of the SSM/I CD-ROM's were used to create the
present data set. SMMR images were collected every 2 to 3 days, whereas SSM/I
data are provided in daily ice-concentration grids. Apart from a number of
small gaps (5 or fewer days) in the record, the only long period for which no
data are available is December 3 of 1987 through January 12 of 1988, inclusive.
As ancillary data, the ETOPO5 global gridded elevation and bathymetry data
(Edwards, 1989) were interpolated to the resolution of the NSIDC data; the
interpolated topographic data are included.
The images are provided in three formats: Hierarchical Data Format (HDF), a
flexible scientific data format developed at the National Center for
Supercomputing Applications; Graphics Interchange Format (GIF); and Macintosh
PICT format. The ice- concentration grids are distributed by NSIDC in HDF
Data Set Citation
Dataset Originator/Creator: Schweitzer, Peter N.
Dataset Title: Monthly average polar sea-ice concentration
Dataset Release Date: 1995
Dataset Release Place: Reston, Virginia
Dataset Publisher: U.S. Geological Survey
Data Presentation Form: remote-sensing image
Other Citation Details: U.S. Geological Survey Digital Data Series
Start Date: 1978-10-25Stop Date: 1991-12-31
Latitude Resolution: 25000
Longitude Resolution: 25000
Data Set Progress
Distribution Media: online
Distribution Format: HDF
Distribution Media: online
Distribution Size: 51 megabytes
Distribution Format: BIL
Role: DIF AUTHOR
Phone: (703) 648-6533
Fax: (703) 648-6252
Email: pschweitzer at usgs.gov
Mail Stop 954 National Center U.S. Geological Survey 12201 Sunrise Valley Drive
Province or State: VA
Postal Code: 20192
Edwards, M.H. 1989, Global Gridded Elevation and Bathymetry (ETOPO5):
Digital raster data on a 5-minute geographic (lat/long) 2160x4320
(centroid-registered) grid. Boulder, Colo.: NOAA
National Geophysical Data Center. 9-track tape, 18.6 megabytes.
McClain, E.P., Pichel, W.G., and Walton, C.C., 1985, Comparative
performance of AVHRR-based multichannel sea surface temperatures:
Journal of Geophysical Research, v. 90, p. 11587-11601.
Smith, E., 1991, A user's guide to the NOAA Advanced Very High
Resolution Radiometer Multichannel Sea Surface Temperature data set
produced by the University of Miami/Rosenstiel School of
Marine and Atmospheric Science: Distributed by the Distributed
Active Archive Center, Jet Propulsion Laboratory, Pasadena,
California. 10 p.
Extended Metadata Properties
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Creation and Review Dates
DIF Creation Date: 1995-08-31
Last DIF Revision Date: 2018-02-05