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38 Fog as a Hydrologic Input

Part 4. Hydrometeorology

  1. LA Sampurno Bruijnzeel1,
  2. Werner Eugster2,
  3. Reto Burkard3

Published Online: 15 APR 2006

DOI: 10.1002/0470848944.hsa041

Encyclopedia of Hydrological Sciences

Encyclopedia of Hydrological Sciences

How to Cite

Sampurno Bruijnzeel, L., Eugster, W. and Burkard, R. 2006. Fog as a Hydrologic Input. Encyclopedia of Hydrological Sciences. 4:38.

Author Information

  1. 1

    Vrije Universiteit, Amsterdam, The Netherlands

  2. 2

    Swiss Federal Institute of Technology, Zürich, Switzerland

  3. 3

    University of Bern, Bern, Switzerland

Publication History

  1. Published Online: 15 APR 2006


This article reviews the hydrologic importance of fog in its various forms. Meteorologically, fog is defined as a ground-touching cloud with a visibility in the horizontal of less than 1000 m. The most widely occurring fog types include radiation fog, sea fog and steam fog, and advection fog, but often fog is also referred to by its location of occurrence (coastal, valley, or mountain fog). The physical processes underlying the various types of fog are described briefly. The use, advantages, and limitations of the most common types of fog collectors, fog detectors, and fog droplet spectrometers are dealt with before embarking on a discussion of techniques for the measurement and modeling of fog deposition on forest vegetation. Results of fog deposition measurements made at selected locations (representing coastal vs. inland, lowland vs. montane, and temperate vs. tropical conditions) are compared. The data confirm the importance of fog interception at many coastal and montane sites across the tropical to mediterranean and warm-temperate climatic spectrum. Under more continental conditions, contributions by fog are usually more modest except on windy mountain ridges and summits. Finally, the paper indicates the chief gaps in knowledge regarding the measurement and importance of fog as a hydrologic input.


  • fog;
  • fog climatology;
  • fog deposition;
  • fog interception;
  • fog measurement;
  • forest hydrologic cycle;
  • modeling;
  • tropical montane cloud forest;
  • water balance