A study of evaporation from tropical rain forest — West Java

Abstract

Measurements of transpiration and interception loss were made from a region of secondary lowland tropical rain forest located in the Janlappa nature reserve, West Java, using soil physical and water-balance methods. For the period of observation, the mean daily transpiration rate was 2.6 mm day−1, (soil-moisture tensions were < 1 bar), a rate which would be obtained with a constant surface resistance of 120 s m−1. Interception models of the Rutter type, in which net-rainfall rate is uniquely related to canopy storage, were found to be unsatisfactory; better results were obtained with models using a stochastic wetting function. Measurements of rain and net rainfall indicated that interception losses were 21% of the gross rainfall. The calculated total evaporation from the site for the year from August 1980 to July 1981 was 1481 mm (886 mm transpiration and 595 mm interception), a value for which the latent heat requirement is identical to the measured net radiational input to the site.