Modelling spatial patterns of near-surface air temperature over a decade of melt seasons on McCall Glacier, Alaska
We examine the spatial patterns of near-surface air temperature (T-a) over a melting glacier using a multi-annual dataset from McCall Glacier, Alaska. The dataset consists of a 10-year (2005-2014) meteorological record along the glacier centreline up to an upper glacier cirque, spanning an elevation...
| Published in: | Journal of Glaciology |
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| Main Authors: | , , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Cambridge Univ Press
2020
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| Subjects: | |
| Online Access: | https://doi.org/10.1017/jog.2020.12 https://repositorio.uchile.cl/handle/2250/175526 |
| Summary: | We examine the spatial patterns of near-surface air temperature (T-a) over a melting glacier using a multi-annual dataset from McCall Glacier, Alaska. The dataset consists of a 10-year (2005-2014) meteorological record along the glacier centreline up to an upper glacier cirque, spanning an elevation difference of 900 m. We test the validity of on-glacier linear lapse rates, and a model that calculates T-a based on the influence of katabatic winds and other heat sources along the glacier flow line. During the coldest hours of each summer (10% of time), average lapse rates across the entire glacier range from -4.7 to -6.7 degrees C km(-1), with a strong relationship between T-a and elevation (R-2 > 0.7). During warm conditions, T-a shows more complex, non-linear patterns that are better explained by the flow line-dependent model, reducing errors by up to 0.5 degrees C compared with linear lapse rates, although more uncertainty might be associated with these observations due to occasionally poor sensor ventilation. We conclude that T-a spatial distribution can vary significantly from year to year, and from one glacier section to another. Importantly, extrapolations using linear lapse rates from the ablation zone might lead to large underestimations of T-a on the upper glacier areas. National Science Foundation (NSF) ARC-0229705 ARC-0714045 ARC-1023509 CONICYT-Program Regional R16A10003 Comisión Nacional de Investigación Cientifica y Tecnológica (CONICYT) CONICYT FONDECYT 3190732 3180145 |
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