PHYSICS AND DISTRIBUTION OF FOG

A FOG CLASSIFICATION SYSTEM IS OUTLINED. THE HORIZONTAL VISUAL RANGE IN FOG IS MOST IMPORTANT TO THE AUTOMOBILE DRIVER, AND FOR THIS REASON ONLY DENSE FOGS ARE LIKELY TO HAVE ANY EFFECTS ON HIS BEHAVIOR IN TRAFFIC. IT IS SHOWN THAT A VARIETY OF MECHANISMS INVOLVING ENERGY, HEAT AND MOISTURE CONTRIBUTE TO THE FORMATION OF FOG. PERTINENT CONDENSATION PROCESSES ARE DISCUSSED FOR ADDITIONAL INSIGHT INTO THE MECHANISMS OF FOG FORMATION. THE BASIC CONCEPTS ARE DESCRIBED OF ATMOSPHERIC VISIBILITY. THE GENERAL THEORY OF VISUAL RANGE IS PRESENTED WITH THE VISIBILITY EQUATION. THIS INDICATES THAT VISIBILITY CAN BE IMPROVED IN FOG BY EITHER OF TWO ACTIONS: (1) THE DECREASE OF LIQUID WATER CONTENT, AND (2) THE DROP SIZE DISTRIBUTION CAN BE ALTERED TO CAUSE THE WATER TO BE CONCENTRATED INTO A FEW LARGE DROPS RATHER THAN A LARGE NUMBER OF SMALL DROPLETS, SO THAT THE AVERAGE DROP RADIUS IS INCREASED. DATA ARE SUMMARIZED ON THE FREQUENCY OF FOG FORMATION. FOG IS MOST FREQUENT AND QUITE LOCAL IN NATURE ALONG THE WEST COAST, IN THE APPALACHIAN MOUNTAINS AND ALONG THE NEW ENGLAND COAST.

• Supplemental Notes:
  • pp 11-17, 2 FIG, 12 REF
• Corporate Authors:

  Itte, University of California, Berkeley

  Proceedings, 2nd Annual Symposium
  ,   United States 
• Authors:
  • Kocmond, W C
  • Pilie, R J
  • Eadie, W J
• Publication Date: 1969-12

Subject/Index Terms

• TRT Terms: Condensation; Equations; Fog; Forming; Moisture content; Physics; Visibility
• Subject Areas: Highways; Safety and Human Factors;

Filing Info

• Accession Number: 00220856
• Record Type: Publication
• Files: TRIS
• Created Date: Jun 1 1970 12:00AM