Ultralow Surface Temperatures in East Antarctica From Satellite Thermal Infrared Mapping: The Coldest Places on Earth
Abstract
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.
- Publication:
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Geophysical Research Letters
- Pub Date:
- June 2018
- DOI:
- Bibcode:
- 2018GeoRL..45.6124S
- Keywords:
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- remote sensing;
- surface temperature;
- thermal mapping;
- air temperature inversion;
- snow and ice;
- Antarctica