Climatology of High-Latitude Air Pollution as Illustrated by Fairbanks and Anchorage, Alaska

Abstract

High latitude communities frequently have severe air pollution problems. The usual situation is the release of moderate amounts of pollutants into an atmosphere with extremely poor dispersion. The poor dispersion is in turn a direct result of the high latitude radiation balance, which in winter is characterized by short days and low solar elevation. At locations north of 60°N, the midwinter day length may vary from 0 to just under 6 hours, and at noon the sun, if it rises at all, is lower in the sky than it would be 45 minutes after sunrise in Los Angeles. The result is a ground-based nighttime inversion which continues through peak traffic hours (throughout the day in some places), coupled with a complete lack of photochemical reactions. Downtown mixing heights as low as 10 m, combined with wind speeds less than 0.5 m s?1, have been measured in Fairbanks. If development in high latitudes is to proceed rationally, these meteorological conditions must be understood, and models developed that take account of them.