GLERL Great Lakes Ice Concentration Data Base, 1960-1979

Summary

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.

Citing These Data

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

We kindly request that you cite the use of this data set in a publication using the following citation example. For more information, see our Use and Copyright Web page.

Overview Table

Category Description
Data format ASCII
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.

Table of Contents

1. Contacts
2. Overview
3. Detailed Data Description
4. Data Access and Related Collections
5. References and Related Publications
6. Acknowledgements
7. Document Information

1. Contacts

Investigator

Dr. Raymond A. Assel
NOAA/GLERL
2205 Commonwealth Boulevard
Ann Arbor, MI 48105-1561

Technical Contact

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

2. Overview

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.

3. Detailed Data Description

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.

File Description
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

Spatial and Temporal Coverage and Resolution

The Great Lakes in 5 km cells, for twice monthly periods during the years 1960-1979.

File Size

The entire data set is 101 MB.

4. Data Access and Related Collections

Data Access

Data available via FTP.

Software and Tools

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:

APPENDIX A
Code Half-month period
1 December 16-31
2 January 1-15
3 January 16-31
4 February 1-14
5 February 15-28
6 March 1-15
7 March 16-31
8 April 1-15
9 April 15-30
 
Code Ice concentration statistics
1 Maximum
2 Minimum
3 Median
4 Average
5 Mode

Related NSIDC Data Collections

5. References and Related Publications

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/

6. Acknowledgements

This data set is maintained at NSIDC with support from the NOAA National Geophysical Data Center.

7. Document Information

Document Authors

Unknown

Document Creation Date

Unknown

Document Revision Date

In July 2006, this document was reformatted. F. Fetterer reviewed this document.

Document URL

http://nsidc.org/data/docs/noaa/g00804_glerl_ice_concentrations/index.html