Variations in snowpack melt on the Greenland ice sheet based on passive-microwave measurements
ABSTRACT. A simple microwave-emlSSlOn model is used to simulate 37 GHz brightness tempera tures associa ted with snow pack-melt co nditions for locati ons across the Greenla nd ice sheet. The simulated valu es a re utilized as threshold values a nd co mpared to d a il y, gridd ed SMMR and SSM/I pass...
| Main Authors: | , , |
|---|---|
| Other Authors: | |
| Format: | Text |
| Language: | English |
| Published: |
1995
|
| Subjects: | |
| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.430.1421 http://www.igsoc.org/journal/41/137/igs_journal_vol41_issue137_pg51-60.pdf |
| Summary: | ABSTRACT. A simple microwave-emlSSlOn model is used to simulate 37 GHz brightness tempera tures associa ted with snow pack-melt co nditions for locati ons across the Greenla nd ice sheet. The simulated valu es a re utilized as threshold values a nd co mpared to d a il y, gridd ed SMMR and SSM/I passive-microwa ve data, in order to reveal region. experiencing melt. The spa ti al ex tent of th e a rea cl ass ifi ed as melting is examined o n a daily, monthly and seasonal (M ay- August) basis for 1979 9 1. The typical seasona l cycle of melt coverage shows melt beginning in la te April, a ra pid in crease in the melting a rea from mid-May to mid-July, a ra pid dec rease in melt ex tent from la te July through mid-August, a nd cessation of melt in late September. Seasonal averages of th e da il y melt extents demonstrate an a ppa rent increase in melt coverage over the 13 year peri od of approxima tely 3.8 % annuall y (signilicant a t the 95 % confidence interval). This in crease is d omina ted by sta tisti call y significant positive trends in melt coverage during July a nd August in th e west and so uthwe t of the ice shee t. 'Ve lind th at a linear correla ti on between microwa\'e-deri ved melt ex tent a nd a surface measure of a bl a ti on rate is signilicant inJune a nd July but not Aug ust, so caution mu. t be exercised in usin g th e microwave-derived melt extents in Aug ust. Nevertheless, kn owledge of th e va ri ability of snow pack melt on the Gree nland ice sheet a deri ved from mi crowave d a ta should prove uscful in dctecting clima te change in the Arctic and examining the impact of clima te cha nge on th e ice shee t. |
|---|