Air Mass Considerations in Fog Optical Modeling.
Abstract
Measurements of fog and haze drop-size distributions taken during the last 4 years at various locations in Germany have been analyzed to determine relations for prediction of infrared extinction coefficients from visibility (actually meteorological range). Mie calculations were applied to the measured drop-size distributions to compute the extinction coefficient at 0.55 micrometers, 4 micrometers, and 10 micrometers. For given values of the meteorological range between 1 and 4 km it was observed that the variation in the extinction coefficient at both 4 micrometers and 10 micrometers exceeded an order of magnitude. The data sets were then subdivided according to the air mass which prevailed over the measurement site at the time of the measurements. With this subdivision according to air mass type the data spread was reduced to ranges which are considered reasonable for measured data. Figures are included which depict this behavior. Algorithms have been developed for predicting the extinction coefficient at 4 micrometers and 10 micrometers from values of the extinction coefficient at 0.55 micrometers. Separate algorithms have been determined for three different air mass types: maritime arctic, maritime polar, and continental polar. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1981
- Accession Number
- ADA097609
Entities
People
- James D. Lindberg
- Louis D. Duncan
Organizations
- Atmospheric Sciences Laboratory