Extent and duration of Antarctic surface melting
Abstract The extent and duration of surface melting on the Antarctic ice shelves and margins of the Antarctic ice sheet are derived from satellite passive-microwave data for 1978–87. The occurrence of surface melting in daily maps of T b is indicated by a marked increase in microwave brightness temp...
| Published in: | Journal of Glaciology |
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| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Cambridge University Press (CUP)
1994
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1017/s0022143000012338 https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143000012338 |
| Summary: | Abstract The extent and duration of surface melting on the Antarctic ice shelves and margins of the Antarctic ice sheet are derived from satellite passive-microwave data for 1978–87. The occurrence of surface melting in daily maps of T b is indicated by a marked increase in microwave brightness temperature (T b ), which is caused by moisture in the near-surface firn. T b increases of more than 30 deg above the annual-mean T b are chosen to indicate melting. Most Antarctic surface melting occurs during December and January. The observed melting is correlated with regional air temperatures, but some melt patterns also appear to be related to katabatic-wind effects. The correlations suggest that the surface melting in Antarctica increases about 3.5 × 10 6 d km 2 per degree of summer temperature increase. The surface-melt index (duration times area of melting) calculated for Antarctica is 24 × 10 6 d km 2 , averaged over nine summers. The observed inter-annual and regional variability is large. Surface melting was most extensive during the 1982/83 summer (36 × 10 6 d km 2 ) and least extensive during the 1985/86 summer (15 × 10 6 d km 2 ). The data indicate a decline in surface melting over the 9 years, but meaningful inferences regarding trends in surface melting are precluded by the large inter-annual variability. |
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