Skip to main content Accessibility help
  • Print publication year: 2011
  • Online publication date: May 2011

28 - Comparison of passive fog gages for determining fog duration and fog interception by a Puerto Rican elfin cloud forest

from Part III - Hydrometeorology of tropical montane cloud forest



Between 5 March and 10 May 2001, the performance of three types of passive fog gages (wire harp WH, standard fog collector SC, and Juvik gage JU) was compared at a wind-exposed Puerto Rican elfin cloud forest site. The gages were used to determine the timing and duration of fog and of fog-induced crown drip. Gage to canopy conversion factors were derived from the ratio between throughfall, and fog collected by the respective gages during periods with fog-only and negligible evaporation loss. The fog gages indicated very similar timing and fog duration, presumably because dense fog prevailed for 75–80% of the time and winds were generally sufficiently strong (4–5 m s−1). Resulting gage-to-canopy factors were 0.12 for WH and SC, and 0.10 for JU. Estimating fog interception by the canopy using these conversion factors gave very similar values for the three gage types (mean rates of 0.15 ± 0.01 mm hour−1). Throughfall typically started about 5 hours after the fog gages indicated the beginning of a fog event. This time lag probably reflects the filling of the storage capacity of the canopy, because wet canopy evaporation was negligible. Integrating the estimated fog interception rates over the time lag suggested an average value of 0.4 mm for the canopy storage capacity during events with fog-only.

Recommend this book

Email your librarian or administrator to recommend adding this book to your organisation's collection.

Tropical Montane Cloud Forests
  • Online ISBN: 9780511778384
  • Book DOI:
Please enter your name
Please enter a valid email address
Who would you like to send this to *
Baynton, H. W. (1968). Ecology of an elfin forest in Puerto Rico. II. Microclimate of Pico Del Oeste. Journal of the Arnold Arboretum 49: 419–430.
Beswick, K. M., Hargreaves, K. J., Gallagher, M. W., Choularton, T. W., and Fowler, D. (1991). Size-resolved measurements of cloud droplet deposition velocity to a forest canopy using an eddy-correlation technique. Quarterly Journal of the Royal Meteorological Society 117: 623–645.
Briscoe, C. B. (1966). Weather in the Luquillo Mountains of Puerto Rico. Rio Piedras, Puerto Rico: Institute of Tropical Forestry.
Brown, S., Lugo, A. E., Silander, S., and Liegel, L. (1983). Research History and Opportunities in the Luquillo Experimental Forest. New Orleans, LA: U.S. Department of Agriculture Forest Service, Southern Forest Experiment Station.
Bruijnzeel, L. A., Eugster, W., and Burkard, R. (2005). Fog as an input to the Hydrological cycle. In Encyclopaedia of Hydrological Sciences, eds. Anderson, M. G. and McDonnell, J. J., pp. 559–582. Chichester, UK: John Wiley.
Chang, S. C., Lai, I. L., and Wu, J. T. (2002). Estimation of fog deposition on epiphytic bryophytes in a subtropical montane forest ecosystem in northeastern Taiwan. Atmospheric Research 64: 159–167.
García-Martinó, A. R., Warner, G. S., Scatena, F. N., and Civco, D. L. (1996). Rainfall, runoff and elevation relationships in the Luquillo Mountains of Puerto Rico. Caribbean Journal of Science 32: 413–424.
García-Santos, G. (2007). An ecohydrological and soils study in a montane cloud forest in the National Park of Garajonay, La Gomera (Canary Islands, Spain). PhD Thesis, VU University Ámsterdam, Ámsterdam, The Netherlands. [].
Goodman, J. (1985). The collection of fog drip. Water Resources Research 21: 392–394.
Hölscher, D., Köhler, L., Dijk, A. I. J. M., and Bruijnzeel, L. A. (2004). The importance of epiphytes to total rainfall interception by a tropical montane rain forest in Costa Rica. Journal of Hydrology 292: 308–322.
Holwerda, F., Burkard, R., Eugster, W. E., et al. (2006). Estimating fog deposition at a Puerto Rican elfin cloud forest site: comparison of the water budget and eddy covariance methods. Hydrological Processes 20: 2669–2692.
Joslin, J. D., Mueller, S. F., and Wolfe, M. H. (1990). Test of models of cloudwater deposition to forest canopies using artificial and living collectors. Atmospheric Environment 24A: 2893–2903.
Juvik, J. O. and Ekern, P. C.. (1978). A Climatology of Mountain Fog on Mauna Loa, Hawai'i Island, Technical Report No. 118. Honolulu, HI: Water Resources Research Center, University of Hawai'i.
Juvik, J. O., and Nullet, D. (1995a). Comments on “a proposed standard fog collector for use in high elevation regions.”Journal of Applied Meteorology 34: 2108–2110.
Juvik, J. O., and Nullet, D. (1995b). Relationships between rainfall, cloud-water interception and canopy throughfall in a Hawaiian montane forest. In Tropical Montane Cloud Forests, eds. Hamilton, L. S., Juvik, J. O., and Scatena, F. N., pp. 165–182. New York: Springer-Verlag.
Monteith, J. L. (1965). Evaporation and the environment. Symposia of the Society for Experimental Biology 19: 245–269.
Schellekens, J., Bruijnzeel, L. A., Wickel, A. J., Scatena, F. N., and Silver, W. L. (1998). Interception of horizontal precipitation by elfin cloud forest in the Luquillo Mountains, eastern Puerto Rico. In Proceedings of the 1st International Conference on Fog and Fog Collection, eds. Schemenauer, R. S. and Bridgman, H. A., pp. 29–32. Ottawa, Canada: IDRC.
Schemenauer, R. S. (1986). Acidic deposition to forests: the 1985 Chemistry of High Elevation Fog (CHEF) Project. Atmosphere–Ocean 24: 303–328.
Schemenauer, R. S., and Cereceda, P. (1994). A proposed standard fog collector for use in high-elevation regions. Journal of Applied Meteorology 33: 1313–1322.
Schemenauer, R. S., and Cereceda, P. (1995). Reply to comments by Juvik and Nullet (1995). Journal of Applied Meteorology 34: 2111–2112.
Schemenauer, R. S., and Joe, P. I. (1989). The collection efficiency of a large fog collector. Atmospheric Research 24: 53–69.
Vong, R. J., Sigmon, J. T., and Mueller, S. F. (1991). Cloud water deposition to Appalachian forests. Environmental Science and Technology 25: 1014–1021.
Weaver, P. L. (1972). Cloud moisture interception in the Luquillo Mountains in Puerto Rico. Caribbean Journal of Science 12: 129–144.
Weaver, P. L. (1995). The colorado and dwarf forests of Puerto Rico's Luquillo Mountains. In Tropical Forests: Management and Ecology, eds. Lugo, A. E. and Lowe, C., pp. 109–141. New York: Springer-Verlag.