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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