During the winters of 1965/66 through 1976/77, NOAA/Great Lakes Environmental Research Laboratory (GLERL) collected weekly ice thickness and stratigraphy data at up to 90 stations per year on the Great Lakes. Data include station name, latitude, longitude and period of record as well as thickness of up to six ice layers, total ice thickness, snow depth (on top of ice), snow condition, ice condition, and ice type code. The data are useful for site-specific shoreline engineering studies, winter navigation projects and remote sensing ground truth. Constraints on the data include the relatively short period of record (eleven seasons maximum for any one station). Additionally, the time series may not reflect the full winter severity range. Nearshore data may not be valid for nearby locations or representative of offshore conditions, and ice type codes (the visual observation code) changed in 1974/75. Both old and new code lists are available.
Access to the GLERL Great Lakes Ice Thickness Data Base, 1966-1979, is unrestricted, but users are encouraged to register for the data. Registered users will receive e-mail notification about any product changes.
Sleator, F.E. 1995. GLERL Great Lakes ice thickness data base, 1966-1979 . Boulder, Colorado USA: National Snow and Ice Data Center. http://dx.doi.org/10.7265/N5KW5CXG
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||Thirty bays and harbors in the Great Lakes.|
|Temporal coverage and resolution||1966-1979|
|Tools for accessing data||The two FORTRAN routines, once compiled, allow the user to select a subset of the database based upon station number. The station number can be read from the coordinate index listing.|
|File size||The total size of the data set is 2.21 MB.|
|Parameter(s)||Lake ice thickness, snow depth, snow condition|
|Metadata access||View metadata|
|Data access||Data are available via FTP.|
Dr. Frederick E. Sleator
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
The Great Lakes Ice Thickness Data Base is made up of observations made by paid and cooperative ice observers who made ice thickness observations at approximately 30 bays and harbors per year during the years 1966-1979. The period of record varies from 4 to 10 years depending on when the site was established. Data were acquired using augers and visual observations.
The contents of each data files are listed below. Data files are ASCII format.
|Station Number||The GLERL station number.|
|Year||Year of observation.|
|Month||Month of observation.|
|Day||Day of observation.|
|Estimation Flag||'E' if data are estimated.|
|Total Thickness||Total ice thickness in inches or centimeters, depending on file.|
|Lake Ice Thickness||Total thickness of any lake ice.|
|Snow Ice Thickness||Total thickness of any snow ice.|
|Columns 8 through 15, four sets of:||Additional Layer Code: See Table 1 for description.
Additional Layer Thickness: Total thickness of layer.
|Water Level||The distance from the top of the water surface to the bottom of the ice sheet.|
|Snow Depth||The depth of snow on the ice.|
|Snow Condition||Numeric code describing the condition of the snow. See Table 2 for details.|
|Ice Condition||Numeric code describing the condition of the ice. See Table 3 for details.|
|Event Code||Numeric code describing significant events affecting the observation site. See Table 4 for details.|
|Event Day||Day which the above event occurred.|
|Event Month||Month which the above event occurred.|
|Visual Observation||Numeric code describing the condition of the ice surface on the lake. See Table 5 for details.|
|Table 1. Additional Layer Codes|
|Table 2. Snow Condition Codes|
|Table 3. Ice Condition Codes|
|10||Piled on Shore|
|Table 4. Event Codes|
|1||Skim ice at measurement site|
|2||Freeze over at measurement site|
|6||Unnatural breakup (ice breaker, etc.)|
|7||Measurement site moved to new location|
|Table 5. Visual Observation Codes|
The following table lists data files as well as files with FORTRAN code designed to access the database. Note that this code was developed on an SGI running IRIX 4.0.1 and is intended to be updated by the user for the appropriate operating environment. The two FORTRAN routines, once compiled, allow the user to select a subset of the database based upon station number. The station number can be read from the coordinate index listing.
|data1.dat||Ice thickness data file for English|
|unitsdata2.dat||Ice thickness data file for metric units|
|display_ice1.f||FORTRAN routine to access English units data|
|display_ice2.f||FORTRAN routine to access metric units|
|ice.loc||Coordinate index for the observation stations|
Station locations are fairly evenly spread along the U.S. shores of Lake Superior with eleven stations concentrated in the Whitefish Bay area, are mostly north of the Kewaunee-Manistee line around Lake Michigan, are mostly near the Straits of Mackinaw on Lake Huron, include only seven stations on Lake Erie/Lake St. Clair, and are along the southeastern and eastern shores of Lake Ontario. The latitude and longitude of the stations is located in the file ice.loc in the format Nxx-xx/Wxxx-xx.
1000680113E01 01 00 1000680120 4 1000680127E01 01 00 5 1000680203 07 07 00 07 01 40802 1000680210E02 02 00 02 10902
The total size of the data set is 2.21 MB.
The metric unit data for station 127 on December 23, 1970 contain an invalid data type. This appears to have resulted from an error in digitizing the data for the additional layers. The English data for this day appears to be unreliable as well.
Data are available via FTP.
Data are available via FTP.
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/
Ice Thickness and Stratigraphy at Nearshore Locations on the Great Lakes, Frederick E. Sleator, NOAA data report ERL GLERL-1-2, July 1978, NTIS number: PB297121 for metric units report PB295671 for English units report
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.