HR: 1330h
AN: H52A-1164    [PDF]
TI: The Mechanism of Water and Sediment Discharges From a Glacier, Based on the Separation by the AR Method
AU: * Chikita, K
EM: chikita@ep.sci.hokudai.ac.jp
AU: Kido, D
EM: kidod@ep.sci.hokudai.ac.jp
AB: The dynamics of water and sediment discharges from Gulkana Glacier, Alaska was examined by analyzing their hourly time series observed in a proglacial river in the glacier-melt season of 2001. The data plots on semi-log paper for recessive part of water and sediment discharges indicate that each of water discharge and sediment discharge consists of "fast" and "slow" components. The fast component probably corresponds to an englacial and subglacial, "channelized" drainage system downstream of snow line in the ablation area, while the slow component is related to a subglacial, "distributed" drainage system upstream of snow line. The hydrological and meteorological observations indicated that suspended sediment concentration (SSC) and water discharge both increased abruptly in ca. 2 days after the maximum air temperature was recorded. Such an _gevent_h would occur by a change of the subglacial drainage system from "distributed" to "channelized". This event probably results from the great erosion of subglacial sediment by the collapse of linked cavities in the distributed drainage system. Flow separation by the AR method, using a numerical filter, was performed for hourly time series of water and sediment discharges. As a result, for the slow component, there existed the high linearity between SSC (mg/l) and water discharge (m3/s) on log-log paper.
DE: 1815 Erosion and sedimentation
DE: 1827 Glaciology (1863)
DE: 1860 Runoff and streamflow
DE: 1863 Snow and ice (1827)
DE: 1894 Instruments and techniques
SC: Hydrology [H]
MN: 2003 Fall Meeting