Links between short-term velocity variations and the subglacial hydrology of a predominantly cold polythermal glacier

被引:63
作者
Copland, L [1 ]
Sharp, MJ
Nienow, PW
机构
[1] Univ Alberta, Dept Earth & Atmospher Sci, Edmonton, AB T6G 2E3, Canada
[2] Univ Glasgow, Dept Geog & Topog Sci, Glasgow G12 8QQ, Lanark, Scotland
关键词
D O I
10.3189/172756503781830656
中图分类号
P9 [自然地理学];
学科分类号
0705 ; 070501 ;
摘要
The Surface velocity of a predominantly cold polythermal glacier (John Evans Glacier, Ellesmere Island, Canada) varies significantly on both seasonal and shorter time-scales. Seasonal variations reflect the penetration of supraglacial water to the glacier bed through significant thicknesses of cold ice. Shorter-term events are associated with periods of rapidly increasing water inputs to the subglacial drainage system. Early-season short-term events immediately follow the establishment of a drainage connection between glacier surface and glacier bed, and coincide with the onset of subglacial outflow at the terminus. A mid-season short-term event occurred as surface melting resumed following cold weather, and may have been facilitated by partial closure of subglacial channels during this cold period. There is a close association between the timing and spatial distribution of horizontal and vertical velocity anomalies, the temporal pattern of surface water input to the glacier, and the formation, seasonal evolution and distribution of subglacial drainage pathways. These factors presumably control h the occurrence of high-water-pressure events and water storage at the glacier bed. The observed coupling between surface water inputs and glacier velocity may allow predominantly cold polythermal glaciers to respond rapidly to climate-induced changes in surface melting.
引用
收藏
页码:337 / 348
页数:12
相关论文
共 33 条
[1]   SEASONAL SURFACE-VELOCITY VARIATIONS ON A SUBPOLAR GLACIER IN WEST GREENLAND [J].
ANDREASEN, JO .
JOURNAL OF GLACIOLOGY, 1985, 31 (109) :319-323
[2]  
[Anonymous], IASH PUBL
[3]   TRANSFER OF BASAL SLIDING VARIATIONS TO THE SURFACE OF A LINEARLY VISCOUS GLACIER [J].
BALISE, MJ ;
RAYMOND, CF .
JOURNAL OF GLACIOLOGY, 1985, 31 (109) :308-318
[4]   THE IMPORTANCE OF PRESSURIZED SUBGLACIAL WATER IN SEPARATION AND SLIDING AT THE GLACIER BED [J].
BINDSCHADLER, R .
JOURNAL OF GLACIOLOGY, 1983, 29 (101) :3-19
[5]   Intra-annual and intra-seasonal flow dynamics of a High Arctic polythermal valley glacier [J].
Bingham, RG ;
Nienow, PW ;
Sharp, MJ .
ANNALS OF GLACIOLOGY, VOL 37, 2003, 37 :181-188
[7]   POLYTHERMAL CONDITIONS IN ARCTIC GLACIERS [J].
BLATTER, H ;
HUTTER, K .
JOURNAL OF GLACIOLOGY, 1991, 37 (126) :261-269
[8]  
COPLAND I, 2000, SPIE P, V4084, P59
[9]   Mapping thermal and hydrological conditions beneath a polythermal glacier with radio-echo sounding [J].
Copland, L ;
Sharp, M .
JOURNAL OF GLACIOLOGY, 2001, 47 (157) :232-242
[10]  
Harbor J, 1997, GEOLOGY, V25, P739, DOI 10.1130/0091-7613(1997)025<0739:IOSDCO>2.3.CO