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Charts show ice extent and concentration three times weekly during the ice season, for all lakes except Ontario, from the 1973/74 ice season to the present. Most charts are annotated to indicate data sources. Straits of Mackinac, Green Bay and Sault Ste. Marie are enlarged as insets, and in some cases, provided as separate charts. The data set is updated annually, usually in August or September. From 1973/74 through 1986/87 charts were prepared by the National Weather Service Forecast Office, Ann Arbor, Michigan. Beginning with the 1987/88 season, the National Ice Center (formerly known as the Navy/NOAA Joint Ice Center) in Suitland, Maryland has prepared the charts. Charts are available as GIF files via ftp. Charts for 1973/74 through 1994/95 are also available on microfiche or as photocopies.
Prior to the 1986-87 ice season, charts were organized by region. The following . common prefixes and their respective region.
el Eastern Great Lakes including Lake Erie, Lake Huron, Georgian Bay, and North Channel
wl Western Great Lakes including Lake Michigan and Superior
ml Whitefish Bay south to Detour, including Sault Ste. Marie and St. Mary's River south to Detour, Michigan
gbl Green Bay
scr St. Clair River
Beginning with the 1986-87 ice season and beyond, all regions were combined into a single chart for each date. Each chart then has a "gl" prefix in the file name to indicate "all" Great Lakes. For example, the file, "el19800104.gif" contains an Eastern Great Lakes chart for 04 January, 1980, while the file "gl19880104" contains a chart including all the Great Lakes.
For information on the most complete data documentation and latest updates please refer to Great Lakes Ice Charts. Please be sure to read the data documentation in detail before working with the data.
Citations in reference lists accompanying published work should be stated:
National Snow and Ice Data Center, compiler. 1995. Great Lakes ice charts. Boulder, CO: National Snow and Ice Data Center. Digital media.
The International Council of Scientific Unions, in Resolution 8 of its 22nd General Assembly, recommended that "...all ICSU members support the fundamental principle of open exchange of data and information for scientific purposes." In the spirit of this resolution, NSIDC/WDC encourages users of data distributed by NSIDC, to consider contributing their own published data to the NSIDC/WDC archive.
If you have published data that you wish to archive and make available to the scientific community, please contact NSIDC User Services to initiate a discussion of the content, form and size of the data set. A list of guidelines for submitting data in electronic form is available.
If you wish to be notified of updates or corrections to these data, please register with NSIDC User Services.
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
e-mail: nsidc@nsidc.org
