2017-09-05. Why Are Arctic Rivers Rising in Winter?

posted Sep 10, 2017, 9:45 PM by Alan Gould
By Emily Underwood, Eos/AGU. For GSS Climate Change chapter 8. Excerpt: Increased glacial melt is boosting winter streamflows by filling aquifers, a new study on an Alaskan river suggests. Alaska’s glacier-fed, braided Tanana River is home to some of the world’s highest-quality salmon fisheries, which have provided sustenance for humans for nearly 12,000 years. Like many Arctic rivers, however, the Tanana and its tributaries are transforming because of rising global temperatures. One prominent change in recent decades is a steady rise in Arctic rivers’ winter flow, which has long puzzled researchers because there is no commensurate increase in precipitation in the Tanana River watershed. Now, a new study suggests that melting glaciers may drive this increased flow by amplifying headwater runoff, the water that drains the mountain region, which is partly lost to the underlying aquifer. In turn, the aquifer feeds the Tanana River year-round. Increased aquifer recharge due to glacier-fed stream corridors may also degrade permafrost from below, further amplifying the seasonal aquifer storage capacity and therefore lowland winter flows.... https://eos.org/research-spotlights/why-are-arctic-rivers-rising-in-winter