Despite a brief heat wave a couple weeks ago, cold temperatures have returned again to Fairbanks with a strong winter inversion.
Recent CSPP NUCAPS sounding is shown below on the left, compared with the Fairbanks sounding on the right. The red line is the vertical temperature profile, and the green line is the dewpoint depression profile. Temperatures are in the dashed blue lines that slant upward and to the right. In the Fairbanks sounding you can see that the temperature starts out very cold at the surface (around -25C) and then it warms up very quickly as you go up (around -10C). That is the signature of an inversion: temperatures that get warmer as you go up.
Recent NUCAPS Sounding
Fairbanks Sounding – Feb 2, 2022
Inversion is especially important in Fairbanks because it suppresses rising air and dispersion making air pollution a bigger problem. The atmosphere typically cools with altitude which helps warmer air parcels to rise and disperse pollutants. Inversions are very stable and the stronger they are, the harder it is for air near the surface to rise and disperse. The result is more smoke and aerosols stay where they are, and even build up if more pollutants are added.
The VIIRS i05 (11.5 um) image below shows a snapshot of how the inversion appears geospatially. The lighter the grey, the colder the temperature. Colder temperatures can be seen in the valleys and the darker warm temperatures can be seen on the higher terrain.