The Association of Low-Level Inversions with Surface Wind and Temperature at Point Arguello

Abstract

Inversions at Point Arguello, California, as detected in 4½ years by rawinsondes at 0400 and 1600 PST, are related to surface wind direction and speed and surface temperatures. Nocturnal inversions based below 1000 ft msl have their maximum frequency in winter and their minimum in summer. Most of them occur with downslope surface winds. Afternoon inversions are most frequent in July and least frequent in January. Nocturnal surface inversions appear to develop when the downslope drainage air from the interior is cool enough to undercut the marine layer. There is evidence that the critical surface temperature for this to take place is 9C.