Modelling the long-term mass balance and firn evolution of glaciers around Kongsfjorden, Svalbard
2015 (English)In: Journal of Glaciology, ISSN 0022-1430, E-ISSN 1727-5652, Vol. 61, no 228, 731-744 p.Article in journal (Refereed) Published
We analyse the long-term (1961-2012) distributed surface mass balance and firn evolution of the Kongsvegen and Holtedahlfonna glacier systems in northwestern Svalbard. We couple a surface energy-balance model to a firn model, with forcing provided from regional climate model output. In situ observational data are used to calibrate model parameters and validate the output. The simulated area-averaged surface mass balance for 1961-2012 is slightly positive (0.08 m w.e. a(-1)), which only fractionally compensates for mass loss by calving. Refreezing of percolating water in spring/summer (0.13 m w.e. a(-1)) and stored water in fall/winter (0.18 m w.e. a(-1)) provides a buffer for runoff. Internal accumulation, i.e. refreezing below the previous year's summer surface in the accumulation zone, peaks up to 0.22 m w.e. a(-1), and is unaccounted for by stake observations. Superimposed ice formation in the lower accumulation zone ranges as high as 0.25 m w.e. a(-1). A comparison of the periods 1961-99 and 2000-12 reveals 21% higher annual melt rates since 2000 and a 31% increase in runoff, which can only in part be ascribed to recent warmer and drier conditions. In response to firn line retreat, both albedo lowering (snow/ice-albedo feedback) and lower refreezing rates (refreezing feedback) further amplified runoff.
Place, publisher, year, edition, pages
2015. Vol. 61, no 228, 731-744 p.
energy balance, glacier modelling, snow physics, surface mass budget
Earth and Related Environmental Sciences
IdentifiersURN: urn:nbn:se:uu:diva-267087DOI: 10.3189/2015JoG14J223ISI: 000363002200010OAI: oai:DiVA.org:uu-267087DiVA: diva2:872843