Existing Visibility Levels in the United States. Isopleth Maps of Visibility in Suburban/Nonurban Area During 1974-76

摘要

Maps are prepared which illustrate median, mid-day visibility levels in suburban/nonurban locations of the continental United States. Median visibilities at 94 locations are determined from cumulative frequency distributions of quality-checked airport observations. Seven locations in the Southwest with photographic photometry or nephelometry data (which agree quite well with the airport data) are also included. The spatial pattern of visibility is demonstrated with isopleth maps for both the annual medians and summertime medians during the years 1974-1976.