Assessing streamflow sensitivity to variations in glacier mass balance

Abstract

We examine long-term streamflow and mass balance data from two Alaskan glaciers located in climatically distinct basins: Gulkana Glacier, a continental glacier located in the Alaska Range, and Wolverine Glacier, a maritime glacier located in the Kenai Mountains. Over the 1966-2011 study interval, both glaciers lost mass, primarily as a result of summer warming, and streamflow increased in both basins. We estimate total glacier runoff via summer mass balance and quantify the fraction of runoff related to annual mass imbalances. In both climates, annual (net) mass balance contributes, on average, less than 20 % of total streamflow, substantially less than the fraction related to summer mass loss (>50 %), which occurs even in years of glacier growth. The streamflow fraction related to changes in annual balance increased significantly only in the continental environment. In the maritime climate, where deep winter snowpacks and frequent rain events drive consistently high runoff, the magnitude of this streamflow fraction was small and highly variable, precluding detection of any existing trend. Furthermore, our findings suggest that glacier mass change is likely to impact total basin water yield, timing of runoff and water quality in the continental environment. However, the impacts of maritime glacier change appear more likely to be limited to water quality and runoff timing.

Mass Balance Evolution of Black Rapids Glacier, Alaska, 1980–2100, and Its Implications for Surge Recurrence

“…Gulkana's conventional mass balances are derived by integrating in situ observations across a regularly updated glacier hypsometry (van Beusekom et al, 2010;O'Neel et al, 2014). Relying on short-duration mass balance modeling (van Beusekom et al, 2010), the USGS obtains glacierwide balances in the stratigraphic time system (i.e., with annual mass balances reaching from one annual glacier-wide mass minimum to the next), which we compare to the Black Rapids balances in the same time system.…”

Impact of Recent Glacial Recession on Summer Streamflow in the Skagit River

“…We refer to 'glacial runoff' specifically as the volume of meltwater derived from surface melt on all of the glaciers as measured at 18 sites on four glaciers (O'Neel et al 2014). Our runoff estimates include snow melt on the glacier surface, as well as snow from previous winters (firn) and glacial ice.…”

A irradiância solar: conceitos básicos

“…Outros parâmetros atmosféricos e oceânicos também registram alterações dos padrões climáticos. Por exemplo, é observado o derretimento das geleiras 4 [60], o aumento do nível do mar 5 [61], a diminuição da espessura do gelo no Ár-tico 6 [62] e um incremento na frequência de precipitação extrema em diferentes regiões [63].…”