|
A suite of subglacial water-pressure records from the 1996 summer field season at Trapridge Glacier, Yukon Territory, Canada, discloses a hydraulic event that cannot readily be explained by known forcings. We suggest that these records indicate covert failure of the pressure sensors caused by at least one large water-pressure pulse. The sign and magnitude of the pulse appears to have varied spatially and the pulse duration was less than the 2 min sampling interval of our data loggers. Laboratory experiments support this interpretation and indicate that the pulse magnitude exceeded 900 m of hydraulic head, roughly 15 times the ice-overburden pressure. Within glaciers, large water-pressure pulses can be generated...
|
Three episodes of strong basal motion occurred at Trapridge Glacier, Yukon Territory, Canada, on 11 June 1995 following the establishment of a connected subglacial drainage system. Responses to these "spring events" are noted in the records for 42 instruments and were recorded throughout the similar to 60 000 m super(2) study area. Strong basal motion during the events is indicated by ploughmeter, load-bolt and vertical-strain records, and abrupt pressure changes in several transducer records denote damage caused by extreme pressure pulses. These pressure pulses, generated by the abrupt basal motion, also resulted in the failure of seven pressure sensors. Records for pressure, turbidity and conductivity sensors...
|
We applied nonparametric statistical techniques to historical streamflow data from five glacierized and four nonglacierized watersheds in southwest Yukon and northwestern British Columbia, Canada, to determine whether rivers with and without catchment glacial cover respond in significantly different ways to a warming climate. The analysis was posed in terms of contrasts between the two groups with respect to long-term trends in annual time series of total river flow volume. We found that glacier-fed rivers grew larger and nival streams progressively smaller over the historical record under an observed regional warming trend. Although some of these trend effects are subtle, the overall result was statistically significant...
|
We applied nonparametric statistical techniques to historical streamflow data from five glacierized and four nonglacierized watersheds in southwest Yukon and northwestern British Columbia, Canada, to determine whether rivers with and without catchment glacial cover respond in significantly different ways to a warming climate. The analysis was posed in terms of contrasts between the two groups with respect to long-term trends in annual time series of total river flow volume. We found that glacier-fed rivers grew larger and nival streams progressively smaller over the historical record under an observed regional warming trend. Although some of these trend effects are subtle, the overall result was statistically significant...
|
We applied nonparametric statistical techniques to historical streamflow data from five glacierized and four nonglacierized watersheds in southwest Yukon and northwestern British Columbia, Canada, to determine whether rivers with and without catchment glacial cover respond in significantly different ways to a warming climate. The analysis was posed in terms of contrasts between the two groups with respect to long-term trends in annual time series of total river flow volume. We found that glacier-fed rivers grew larger and nival streams progressively smaller over the historical record under an observed regional warming trend. Although some of these trend effects are subtle, the overall result was statistically significant...
|
View more...
|