[1] Dep. of Soil Science, Univ. of Wisconsin, 1525 Observatory Dr., Madison, WI 53706-1299, United States
[2] Ohio State Univ., Byrd Polar Research Ctr., 1090 Carmack Rd., Columbus, OH 43210-1002, United States
[3] Dep. of Geography, Univ. of Cincinnati, Cincinnati, OH 45221, United States
[4] Dep. of Geography, Univ. of Delaware, Newark, DE 19716, United States
[5] International Permafrost Assoc., P.O. Box 7, Woods Hole, MA 02543, United States