Estimation of leaf wetness duration using empirical models in northwestern Costa Rica

Leaf wetness duration (LWD) estimation models developed in the midwestern U.S. were assessed for portability to northwestern Costa Rica during wet and dry seasons. The CART/SLD/Wind (CART) model overestimated LWD by 5.4 h at five sites in northwestern Costa Rica during the 1999 wet season. The Fuzzy (FL) model, in contrast, estimated LWD at the same sites within 3 h. During the 2000-2001 and 2002-2003 dry seasons, both models underestimated LWD at most sites, probably due to the prevalence of less humid conditions than in the temperate climate of the midwestern U.S. However, accuracy of the FL model was substantially improved when a correction factor was utilized during the 2002-2003 dry season, indicating that this model could be adjusted to estimate LWD in a semi-arid climate with acceptable accuracy. The results suggested that the adjusted FL model could estimate LWD accurately in other tropical regions with climate regimes similar to northwestern Costa Rica.