While our study was limited to only a 
portion of the upper Midwestern U.S. and Canada, 
the scope could be extended over most of the 
northern hemisphere. Moreover, temporal coherence 
of ice-off between certain lakes (see Wynne et al. in 
press) could be used to reduce the lake set to a series 
of lakes which are representative of a region, 
thereby reducing interpretation requirements. 
With the continuing need for detection of 
climate change, and the demonstrated relevance 
(e.g., Wynne and Lillesand, 1993, Assel and 
Robertson, 1995) and efficiency of lake ice 
monitoring for this task, we believe that this study 
provides an important foundation for eventual 
operational monitoring of the date of lake ice 
breakup on a regional to global scale. 
ACKNOWLEDGMENTS AND DISCLAIMER 
Seventy-five percent of this research was 
funded by the U.S. Department of Energy's (DOE) 
National Institute for Global Environmental Change 
(NIGEC) through the NIGEC Great Plains Regional 
Center at the University of Nebraska-Lincoln. (DOE 
Cooperative Agreement No. DE-FC03-90ER61010.) 
Financial support does not constitute an endorsement 
by DOE of the views expressed in this paper. 
This work was also partially supported by 
the North Temperate Lakes Long-Term Ecological 
Research site of the National Science Foundation 
(grants BSR8514330 and DEB9012313) and the 
Global Change Fellowship Program of the National 
Aeronautics and Space Administration (grant NGT- 
30034). 
Special thanks go to Dr. Frank L. Scarpace, 
Dr. Peter Weiler, Larry Seidl, and Marcia Verhage 
of the University of Wisconsin-Madison 
Environmental Remote Sensing Center. We would 
also like to thank Dr. John J. Magnuson, Director of 
the University of Wisconsin-Madison Center for 
Limnology. 
92 
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