Cold temperatures across the North Slope of Alaska

February 4th, 2021 |

Suomi NPP VIIRS Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Infrared Window (11.45 µm) images [click to enlarge]

Suomi NPP VIIRS Infrared Window (11.45 µm) images (above) revealed a large area of cold surface infrared brightness temperatures across much of the North Slope of Alaska on 04 February 2021 — with the coldest IR temperature being -56ºC (darker shades of violet) about 30 miles south-southeast of Umiat (PAUM) on the 1221 UTC image. The surface air temperature at the nearby Umiat RAWS site around that time was -55ºF (-48.3ºC). Narrow fingers of cold air drainage into some of the river valleys along the northern slopes of the Brooks Range (topography) were also apparent.

The corresponding GOES-17 “Clean” Infrared Window (10.35 µm) images (below) also showed the large area of cold surface IR brightness temperatures, but the temperatures were not as cold (in the -40 to -50ºC range), and the small-scale signatures of various topographical features were not depicted.

GOES-17 "Clean" Infrared Window (10.35 µm) images [click to enlarge]

GOES-17 “Clean” Infrared Window (10.35 µm) images [click to enlarge]

A toggle between Infrared Window images from Suomi NPP VIIRS and GOES-17 (10.35 µm) at 1223 UTC is shown below.

Infrared Window images from Suomi NPP VIIRS and GOES-17 (10.35 µm) at 1223 UTC [click to enlarge]

Infrared Window images from Suomi NPP VIIRS (11.45 µm) and GOES-17 (10.35 µm) at 1223 UTC [click to enlarge]