Authors: Rasmussen, L.A.; Wenger, J.M.

Source: Journal of Glaciology, Volume 55, Number 192, September 2009 , pp. 619-624(6)

Publisher: International Glaciological Society

Abstract:

In 2003-07 summer balance was measured at altitudes between 1700 and 3382 m a.s.l. on two glaciers on Mount Rainier, Washington State, USA (46.85° N, 121.72° W; 4400 m a.s.l.): south-facing Nisqually Glacier and east-northeast-facing Emmons Glacier. Upper-air temperatures at the nearest gridpoint in the NCEP/NCAR reanalysis database are used in a distributed (over altitude) positive-degree-day (PDD) model. For each glacier the model used the same coefficients at all altitudes, for all years. The rms model error was 0.65 (r² = 0.87) and 0.78 m a^-1 w.e. (r² = 0.93) for Nisqually and Emmons Glaciers, respectively. Although PDD work generally uses different coefficients for snow and ice surfaces, and the duration of exposure of those surfaces varies with altitude, error in this single-coefficient model is nearly uncorrelated with altitude. Values of coefficients obtained are within the range of those found in other PDD work. The degree-day coefficient, however, differs markedly between the two glaciers, and is shown to be controlled by the difference between them in vertical gradient of measured summer balance. It is smaller for Nisqually Glacier, where solar radiation is a stronger contributor to melt; and larger for Emmons Glacier, where it is a weaker contributor. Over 1948-2007, when the model calibrated over 2003-07 was applied to the upper-air temperatures, estimated summer balance was ∼0.4 m a^-1 less negative over 1962-83 than before and ∼0.6 m a^-1 less negative than after, corresponding roughly with changes of the northeast Pacific sea-surface temperatures.

Document Type: Research article

DOI: http://dx.doi.org/10.3189/002214309789471012

Publication date: 2009-09-01

More about this publication?

• The Journal of Glaciology is published six times per year. It accepts submissions from any discipline related to the study of snow and ice. All articles are peer reviewed. The Journal is included in the ISI Science Citation Index.
• Editorial Board
• Information for Authors
• ingentaconnect is not responsible for the content or availability of external websites

Related content

• In this: publication
• By this: publisher
• In this Subject: Geology ,  Meteorology & Climatology
• By this author: Rasmussen, L.A. ;  Wenger, J.M.

Website © Publishing Technology. Article copyright remains with the publisher, society or author(s) as specified within the article.

• Terms and conditions
• Privacy policy
• Information for advertisers