SPATIAL AND TEMPORAL CHARACTERIZATION OF HOAR FORMATION IN CENTRAL GREENLAND USING SSM/I BRIGHTNESS TEMPERATURES

被引:33
作者
SHUMAN, CA [1 ]
ALLEY, RB [1 ]
机构
[1] PENN STATE UNIV,CTR EARTH SYST SCI,UNIV PK,PA 16802
关键词
D O I
10.1029/93GL02810
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
The summertime formation and burial of low-density, coarse-grained, hoar layers in the snow of central Greenland can be mapped using satellite passive-microwave data. Variations in a signal derived from Special Sensor Microwave/Imager (SSM/I) brightness temperature trends correlate temporally and spatially with hoar complex evolution over almost-equal-to 120,000 km2 of the Greenland ice sheet's dry firn facies. Observations at the Greenland Ice Sheet Project II (GISP2) site indicate that changes in surface conditions and brightness temperatures correspond to four hoar events over two summers, as expected from theory. Following a snowfall, the smooth, high-density surface reflects some emitted, 37 GHz, horizontally-polarized (H) radiation but little vertically-polarized (V) radiation. Progressive surface roughness increases and density decreases during hoar formation cause a gradual decrease in H reflection. Formation and burial of a hoar layer thus causes a slow decrease followed by an abrupt increase in the V/H ratio. Hoar layers have been used to date the GISP2 ice core through the entire Holocene; archived microwave data now can be used to assess the timing and frequency of the formation of these stratigraphic markers in central Greenland.
引用
收藏
页码:2643 / 2646
页数:4
相关论文
共 8 条
[1]   ABRUPT INCREASE IN GREENLAND SNOW ACCUMULATION AT THE END OF THE YOUNGER DRYAS EVENT [J].
ALLEY, RB ;
MEESE, DA ;
SHUMAN, CA ;
GOW, AJ ;
TAYLOR, KC ;
GROOTES, PM ;
WHITE, JWC ;
RAM, M ;
WADDINGTON, ED ;
MAYEWSKI, PA ;
ZIELINSKI, GA .
NATURE, 1993, 362 (6420) :527-529
[2]   SUMMERTIME FORMATION OF DEPTH HOAR IN CENTRAL GREENLAND [J].
ALLEY, RB ;
SALTZMAN, ES ;
CUFFEY, KM ;
FITZPATRICK, JJ .
GEOPHYSICAL RESEARCH LETTERS, 1990, 17 (13) :2393-2396
[3]   CONCERNING THE DEPOSITION AND DIAGENESIS OF STRATA IN POLAR FIRN [J].
ALLEY, RB .
JOURNAL OF GLACIOLOGY, 1988, 34 (118) :283-290
[4]  
[Anonymous], J GLACIOL
[5]  
BENSON CS, 1962, SIPRE70 US ARM RES R
[6]  
FIACCO RJ, CHARACTERISTICS POSS
[7]   PREDICTED TIME-SCALES FOR GISP2 AND GRIP BOREHOLES AT SUMMIT, GREENLAND [J].
SCHOTT, C ;
WADDINGTON, ED ;
RAYMOND, CF .
JOURNAL OF GLACIOLOGY, 1992, 38 (128) :162-168
[8]  
SHUMAN CA, 1993, ANN GLACIOL, V17, P183