Energy Balance and Snow Melt on the Kahiltna Glacier, Central Alaska Range

• Main Author: Winski, Dominic
• Format: Text
• Language: unknown
• Published: DigitalCommons@UMaine 2011
• Subjects: Kahiltna Glacier snowpack measurement; Sea level increases; Climate; Glaciology; Oceanography; Other Earth Sciences; alaska range; glacier; glaciers; Alaska
• Online Access: https://digitalcommons.library.umaine.edu/etd/1613; https://digitalcommons.library.umaine.edu/context/etd/article/2642/viewcontent/WinskiD2011.pdf

Paleoclimate and mass balance studies depend on the determination of the physical and chemical relationships between melt water and the snowpack, particularly in Central Alaska where glaciers have had consistent negative mass balances for several decades and are among the leading contributors to global sea level rise. To explore these relationships in Central Alaska, I constructed a surface energy balance model based on meteorological observations from May 26, 2010 to June 11, 2010, at Kahiltna Base Camp in Denali National Park, in order to determine the principal modes of energy transfer into the ice and how they are affected by atmospheric variables. The physical properties of grain size, snow hardness, water content and density were measured within the top 1.8 meters of snowpack twice daily between May 26-June 10, 2010 to determine the effects of melt on snow stratigraphy. Snowpit samples were collected and analyzed for 8D, major ion, and trace metal concentrations. At one site, samples were collected on May 13 and June 10, 2010 while at a nearby site samples were collected during the morning and evening of June 7. Through the analysis of these samples the changes in chemical profiles imposed by melt can be assessed on timescales of one day and one month. Results indicate that incoming solar radiation is the dominant source of energy transferred to the ice with an average flux of 47 W/m2. Both temperature index and energy balance models may be appropriate at this site, although high (r2=0.61) correlations with temperature and melt rate are due to the positive relation between air temperature and incoming solar radiation rather than to large sensible and longwave fluxes. The energy balance model was applied to the period 1971-2000 across the Central Alaska Range to produce a realistic equilibrium line altitude at 2000 meters elevation and glacial mass balance of -0.60 meters per year. The mass of surface snow melted at Kahiltna Base Camp is significantly correlated (r2=0.56) with both snowpack density and ...