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GLERL 2000 Milestone Reports
GOAL: IMPLEMENT SEASONAL TO INTERANNUAL CLIMATE FORECASTS
OBJECTIVE 2: Maintain and Improve Observing and Data Delivery Systems
PM: Number of operational data sets updated, developed, and produced.
Milestone: Complete updating the digital Great Lakes icecover data set.
Scientist: R. A. Assel
Purpose: Provide improved (computer) access to historical Great Lakes ice cover data that up until now was available only in paper format. This work is part of a project to update the existing GLERL Great Lakes ice cover database and climatology (Assel 1983, Assel et al. 1983).
Efforts: In 1994, under the auspices of NOAA's Earth System and Data Information Management (ESDIM) Program, a project to update a 20-year (1960-1979) computerized ice concentration climatology and database was initiated. The National Ice Center (NIC) and Canadian Ice Service (CIS) contributed historic ice charts for the winters from 1973 to 1995. Methods and procedures to catalogue, code, digitize, quality control, and format the digitized ice charts were developed over several years. Much of this work was accomplished through the University of Michigan's Cooperative Institute for Limnology and Ecosystem Research. Equipment used in this project included a large electronic digitizing table, an HP workstation, and several IBM type computers. Standard ARC/INFO functions, Arc Macro Language script, Fortran code, and Interactive Data Language code were developed for the reduction and quality control of the paper ice charts.
Customers: Operational users of these data include the National Ice Center, the Canadian Ice Service, the U.S. Coast Guard, The U.S. Army Corps of Engineers, and the National Snow and Ice Data Center. Within GLERL these data will be useful for statistical analysis of Great Lakes ice cover, analysis of winter regional climate and climate change during the last three decades of the 20th century, developing improved lake thermodynamic - lake evaporation models, and developing improved empirical- statistical and improved conceptual process models of ice cover.
Significance: There has been and continues to be concern over global warming and its potential impacts. The cryosphere is an important indicator of climate and climate change, and lake ice is a sensitive index of regional winter climate. Therefore, the availability of improved information on Great Lakes ice is timely. These data will be useful in the analysis of winter regional climate change and climate variability studies well into the 21st Century.
Success: The work to computerize and quality control 812 paper copy composite ice charts has been completed. In autumn of 1999 the NIC and CIS were provided with copies of the digitized ice charts for one winter for their evaluation. Feedback was provided in spring 2000 and it now appears that a meeting between CIS, GLERL, and NIC is needed to resolve issues. The paper copy ice chart data reduction portion of this project is completed, and a technical memorandum (Norton et al. 2000) has been written documenting in great detail the methods and procedures developed in all aspects of digitizing and quality control of these data.
Next Steps: The NIC started to make Great Lakes ice chart analysis using a Geographic Information System in 1995. GLERL has obtained a copy of these data. Work is underway to process these digital ice charts (put them in our standard format and quality control them). Once this work is completed, these data will be used to augment our computerized ice cover data base and make a statistical analysis of the ice cover to update our Great Lakes ice cover climatology. The completed ice cover climatology and data base will be made available to the public after climatological analysis has been completed and published (hopefully within a year).
References:
Assel, R.A., 1983. A computerized ice concentration data base for the Great Lakes. NOAA DR ERL GLERL-24. Great Lakes Environmental Research Lab., Ann Arbor, MI. Available on the Internet at: GLERL Technical Reports
Assel, R.A., F.H. Quinn, G.A. Leshkevich, and S.J. Bolsenga, 1983. Great Lakes ice atlas. NOAA Atlas No. 4. Great Lakes Environmental Research Lab., Ann Arbor, MI. The digital data from this atlas as well as the data base upon which is based is available on the Internet at the National Snow and Ice Data Center (NSIDC)
Norton, D.C, and others. 2000. Great Lakes Ice Cover Data Rescue Project. 2000 NOAA TM ERL-GLERL-117, Great Lakes Environmental Research Laboratory, Ann Arbor, MI. Available on the Internet at: GLERL Technical Reports
Last updated: 2003-11-06 mbl