ARCSS039: Thaw Depth, Toolik Lake, Alaska, 1995 and 1996 -------------------------------------------------------- Steven Oberbauer, Florida International University Thaw depths were measured at the Toolik Lake Field Station during the summers of 1995 and 1996 from plots located on the east-facing slope above the entrance stream to the lake. Included are the following parameters: Julian day, treatment, replicate, tussock depth of thaw (cm), and intertussock depth of thaw (cm; with a precision of 0.5 cm). Treatments were control, snow removal, and snow removal plus soil heating. Soil heating was done at 10 cm depth using greenhouse cold frame heating cables, and plots were heated 2 hours per day. Six replicates of each treatment were set up in randomized blocks located 3 m apart through tussock and intertussock, one site of each type per plot with the same marked site measured throughout the growing season. Each 1.5m x 1.5m plot was analyzed weekly or more frequently from May to the end of August. In 1995, snow was removed from the plots on May 3 and May 12, with subsequent soil heating beginning on May 12. In 1996, snow was removed from the plots on May 3, and soil heating started on May 5. Measurements were made with a steel probe with rounded end pressed until the frozen soil was contacted. Soil surface was considered to be the base of tillers for tussock and the base of green moss for intertussock areas. Data files are in both ASCII (dpthtw95.dat, dpthtw96.dat) and MS Excel (dpthtw95.xls, dpthtw96.xls) formats.