CGRG Bibliography of Canadian Geomorphology
Search Results
Author : Boon, S.; and Sharp, M.
Date : 2001.
Title : Impact of high latitude chinook events on Arctic glacier hydrology.
Publication : Annual Scientific Meeting of the Canadian Geophysical Union. May 14-17, 2001, University of Ottawa, Ottawa.
Issue :
Page(s) :
Abstract
On 28-29 July, 2000, a chinook event, characterised by high air temperatures and strong winds, was observed at John Evans Glacier, Ellesmere Island (JEG; 79°40'N 74°00'W). The chinook resulted in a marked increase in surface melt rates, leading to elevated supra- and proglacial water levels and increased discharge. Given the apparent impact of this event on the hydrological system of the glacier, this paper aims to (i) identify the synoptic conditions under which it occurred, (ii) quantify its absolute and relative impact on surface melt rates and runoff, and (iii) evaluate the likely recurrence interval of events of this type. Synoptic charts and data from the NCEP reanalysis indicate that the event occurred while there was a large high to the north of Ellesmere Island and a deep low in Baffin Bay. This resulted in a strong west-to-east flow over the northern sector of the Greenland Ice Sheet with descending flow on the NW side reaching Ellesmere Island. Wind speeds on JEG at 1150m a.s.l. averaged 8.1 m s -1 over the period of the event, with peak hourly wind speeds reaching 11.6 m s -1 . Air temperatures reached 8°C, and rates of surface lowering measured by an ultra-sonic depth gauge averaged 9 cm d -1 . Melt rates were calculated from on-site measurements of net radiation, air temperature, relative humidity and wind speed, using the energy balance model of Brock and Arnold (2000), and the fractional contribution to annual runoff and mass balance was determined. Meteorological data from Alert and Eureka were also examined to determine (a) the extent of the July 2000 event, and (b) the incidence of similar events in the historical record.
Bibliography of Canadian Geomorphology