Changes in Catchment-Scale Recession Flow Properties in Response to Permafrost Thawing in the Yukon River Basin

Permafrost influences the hydrologic response of a catchment. In this study, we test the ability of recession flow analysis to reflect thawing of permafrost at the catchment scale for the well-studied Yukon river basin (YRB), covering large portions of Alaska, USA and parts of Canada. The changes in the recession flow properties detected in the YRB agree well with observations of permafrost thawing across central Alaska. In addition, there is good agreement between the relative increases in recession flow intercept (a proxy for effective depth to permafrost) and the relative annual increases in groundwater flow (independently assessed as a permafrost thawing effect) in the YRB catchments that have exhibited such groundwater flow increases. This study demonstrates the utility of recession flow analysis to reflect catchment-scale changes in permafrost across a variety of permafrost conditions. The strength of this method is that it requires only daily observations of streamflow to reflect permafrost thawing on much larger measurement support scales than the local scales of direct permafrost observations. Copyright (C) 2009 Royal Meteorological Society