FORECASTING BLOWING DUST AT GEORGE AFB, CALIFORNIA
Abstract
The main factors in causing blowing dust at George AFB are the combination of steady wind speed and gusts, with steady wind speed as the main factor. When the steady wind speed reaches its critical value the loose dust lying on the desert floor will be lifted to a height sufficient to restrict the visibility. These values are, 17 knots for a Northerly wind, 26 knots for a Southerly wind, and 25 knots for a Westerly wind. The critical value increases to 30 knots during the months April through September for a Southerly wind, and from June through September for a Westerly wind. This is a result of the ''baking action'' of the desert floor by the sun and the increase in desert foliage. Gusts alone without a sufficiently strong steady wind, will only lift the dust a few feet above the ground, it will then settle on the lee side of the brush. After the dust has been lifted by the steady wind the gusts lift larger quantities of dust into the atmosphere and force it to greater heights. The principal source regions for blowing dust are; the area in the vicinity of the mouth of Cajon Pass (to the South), the dry lake beds and mesa between George AFB and Palmdale (to the West), and the Mojave River Valley (to the North). The main difficulty in forecasting Blowing Dust at George AFB is whether the main body of dust will be carried through George AFB or on the outer perimeters. With a South wind, the air is funnelled through Cajon Pass and fanned out over the desert, while the center of the stream moves Northward through Apple Valley. The predominate dust layer travels with the main stream, with George AFB lying on the outer fringes. Blowing dust is not a problem during the summer months with a South wind, except when associated with thunderstorms.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1963
- Accession Number
- AD0403509
Entities
People
- Kenneth W. Bickett