Ultralow Surface Temperatures in East Antarctica From Satellite Thermal Infrared Mapping: The Coldest Places on Earth
We identify areas near the East Antarctic ice divide where <−90 °C surface snow temperatures are observed in wintertime satellite thermal-band data under clear-sky conditions. The lowest temperatures are found in small (<200 km2) topographic basins of ~2 m depth above 3,800 m elevation. Approx...
Main Authors: | , , , , , , , , |
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Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2018
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Subjects: | |
Online Access: | https://hdl.handle.net/20.500.12613/8745 |
Summary: | We identify areas near the East Antarctic ice divide where <−90 °C surface snow temperatures are observed in wintertime satellite thermal-band data under clear-sky conditions. The lowest temperatures are found in small (<200 km2) topographic basins of ~2 m depth above 3,800 m elevation. Approximately 100 sites have observed minimum surface temperatures of ~−98 °C during the winters of 2004–2016. Comparisons of surface snow temperatures with near-surface air temperatures at nearby weather stations indicate that ~−98 °C surfaces imply ~−94 ± 4 °C 2-m air temperatures. Landsat 8 thermal band data and elevation data show gradients near the topographic depressions of ~6 °C km−1 horizontally and ~4 °C m−1 vertically. Ultralow temperature occurrences correlate with strong polar vortex circulation. We discuss a conceptual model of radiative surface cooling that produces an extreme inversion layer. Further cooling occurs as near-surface cold air pools in shallow high-elevation topographic basins, moderated by clear-air downwelling radiation and heat from subsurface snow. Temple University. College of Science and Technology Earth and Environmental Science |
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