Ice concentration grids for 1960 to 1979 are archived for half-month periods, generally December through April. Data values are coded to the nearest ten percent for each 5 x 5 km grid square. A file of geographic coordinates of the center of each grid cell is included for each lake. A file of ice climatology data for each lake includes average, median and mode for each grid cell for each half-month period. Over 2800 charts were digitized to produce this data base. Charts were prepared by NOAA/National Weather Service Forecast Office in Ann Arbor, U.S. Coast Guard Ninth District Ice Navigation Center in Cleveland, and by the Canadian Atmospheric Environment Service. Chart data sources include NOAA satellite, U.S. Coast Guard side-looking airborne radar (SLAR) and aerial visual reconnaissance, Canadian Coast Guard SLAR and aerial visual reconnaissance, and Atmospheric Environment Service analyses. The data were given to NSIDC by the NOAA Great Lakes Environmental Research Laboratory (GLERL), Ann Arbor, MI.
Access to the GLERL Great Lakes Ice Concentration Data Base, 1960-1979, is unrestricted, but users are encouraged to register for the data. Registered users will receive e-mail notification about any product changes.
Assel, R.A. 1983. GLERL Great Lakes ice concentration data base, 1960-1979. Boulder, Colorado USA: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N5G44N6G
The following example shows how to cite the use of this data set in a publication. For more information, see our Use and Copyright Web page.
|Spatial coverage and resolution||Great Lakes 5 km grids|
|Temporal coverage and resolution||1960-1979, half-months for November-April|
|Tools for accessing data||A series of ten FORTRAN routines is included in order to facilitate the extraction and use of the data.|
|File size||The entire data set is 101 MB.|
|Parameter(s)||Lake ice concentration|
|Metadata access||View metadata|
|Data access||Data are available via FTP.|
Dr. Raymond A. Assel
2205 Commonwealth Boulevard
Ann Arbor, MI 48105-1561
NSIDC User Services
National Snow and Ice Data Center
CIRES, 449 UCB
University of Colorado
Boulder, CO 80309-0449 USA
phone: +1 303.492.6199
fax: +1 303.492.2468
form: Contact NSIDC User Services
An ice concentration data base covering a 20-winter period from 1960 to 1979 was established as part of a study to update an existing Great Lakes ice-cover climatology. Great Lakes ice charts were produced by United States and Canadian government agencies during the 20 years between 1960 and 1979. Over 2800 of these charts were used in developing this digital database. A copy of the NOAA data report, A Computerized Ice Concentration Data Base for the Great Lakes, is strongly recommended for use of the data base, but is not required.
There are three types of files: the original ice concentration files, the climatology data, and the date index and grid cell coordinate index. The following are the files containing the data as well as the data extraction routines. Note that the extraction routines were developed on an SGI running IRIX 4.0.1 and are intended for use as a prototype and may require some updates for the appropriate operating system.
|erie_lake.dat||Ice concentration file for Lakes Erie and St. Clair|
|erie_clim.dat||Climatology data for Lakes Erie and St. Clair|
|erie_date.dat||Date index and Coordinate index for Erie and St. Clair|
|huron_lake.dat||Ice concentration file for Lake Huron|
|huron_clim.dat||Climatology data for Lake Huron|
|huron_date.dat||Date index and Coordinate index for Lake Huron|
|mich_lake.dat||Ice concentration file for Lake Michigan|
|mich_clim.dat||Climatology data for Lake Michigan|
|mich_dat.dat||Date index and Coordinate index for Lake Michigan|
|ontario_lake.dat||Ice concentration file for Lake Ontario|
|ontario_clim.dat||Climatology data for Lake Ontario|
|ontario_date.dat||Date index and Coordinate index for Lake Ontario|
|superior_lake.dat||Ice concentration file for Lake Superior|
|superior_clim.dat||Climatology data for Lake Superior|
|superiod_date.dat||Date index and Coordinate index for Lake Superior|
|read_erie_climate.f||Extraction routine for Erie Climatology|
|read_erie_image.f||Extraction routine for Erie ice images|
|read_huron_climate.f||Extraction routine for Huron Climatology|
|read_huron_image.f||Extraction routine for Huron ice images|
|read_mich_climate.f||Extraction routine for Michigan Climatology|
|read_mich_image.f||Extraction routine for Michigan ice images|
|read_ontario_climate.f||Extraction routine for Ontario Climatology|
|read_ontario_image.f||Extraction routine for Ontario ice images|
|read_superior_climate.f||Extraction routine for Superior Climatology|
|read_superior_image.f||Extraction routine for Superior ice images|
The Great Lakes in 5 km cells, for twice monthly periods during the years 1960-1979.
The entire data set is 101 MB.
Data available via FTP.
The FORTRAN routines are included in order to facilitate the extraction and use of the data. There are two routines for each lake. The routines entitled read_*_image.f are used to extract the individual digitized ice charts. The routines entitled read_*_climate.f are used to extract the ice concentration climatology files. These files were developed for IRIX 4.0.1 and may require some updates for other operating systems. The files to extract each ice chart allow the user to narrow a query based upon time and geographic location. The user will be prompted to enter the ranges for which data are required. The data extends from December 1960 to April 1979 for the winter months only (December through April). The geographical ranges vary by lake with the latitude and longitude ranges changing accordingly. Note that the longitude is measured in degrees West and is considered a negative number. The user may export the data based upon default criteria; i.e. the entire lake grid. The files to extract the climatology charts for each lake also allow the user to extract a portion of an grid based upon geographical constraints, latitude and longitude. Additionally the user can select data using the half month period and statistics codes used in the NOAA/GLERL data report. These codes, from Appendix A, follow:
|Code||Ice concentration statistics|
A Computerized Ice Concentration Data Base for the Great Lakes, Raymond A. Assel, NOAA Data Report ERL GLERL-24, April 1983 NTIS order number: PB83-233013 (National Technical Information Service, 5285 Port Royal Rd, Springfield VA 22161; telephone 703-487-4650).
Assel, R. A. Great Lakes weekly ice cover statistics. NOAA Technical Memorandum GLERL-133. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 27 pp. (2005). ftp://ftp.glerl.noaa.gov/publications/tech_reports/glerl-133/
Assel, R. A. Computerized National Weather Service Great Lakes ice reports for winter seasons 1899-1970. NOAA Technical Memorandum GLERL-130. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 31 pp. (2004). ftp://ftp.glerl.noaa.gov/publications/tech_reports/glerl-130/
Assel, R. A. A Laurentian Great Lakes ice cover climatology. Proceedings of the 61st Annual Meeting of the Eastern Snow Conference, Portland, Maine, June 9-11, 2004. 2 pp. (2004). http://www.glerl.noaa.gov/pubs/fulltext/2004/20040027.pdf
Assel, R. A., F. H. Quinn, and C. E. Sellinger. Hydro-climatic factors of the recent drop in Laurentian Great Lakes water levels. Bulletin of the American Meteorological Society 85(8):1143-1151 (2004). http://www.glerl.noaa.gov/pubs/fulltext/2004/20040017.pdf
Assel, R. A., S. Drobot, and T. E. Croley, II. Improving 30-day Great Lakes ice cover outlooks. Journal of Hydrometeorology 5(4):713-717 (2004). http://www.glerl.noaa.gov/pubs/fulltext/2004/20040016.pdf
Assel, R. A., S. Drobot, and T. E. CROLEY, II. Improving monthly Great Lakes ice cover outlooks. NOAA Technical Memorandum GLERL-129. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 22 pp. (2004). ftp://ftp.glerl.noaa.gov/publications/tech_reports/glerl-129/
Assel, R. A. Lake Erie ice cover climatology -- basin averaged ice cover: winters 1898-2002. NOAA Technical Memorandum GLERL-128. NOAA, Great Lakes Environmental Research Laboratory, Ann Arbor, MI, 15 pp. (2004). ftp://ftp.glerl.noaa.gov/publications/tech_reports/glerl-128/
This data set is maintained at NSIDC with support from the NOAA National Geophysical Data Center.
In July 2006, this document was reformatted. F. Fetterer reviewed this document.