Modelling rainfall interception by a lowland tropical rain forest in northeastern Puerto Rico

Abstract

Recent surveys of tropical forest water use suggest that rainfall interception by the canopy is largest in wet maritime locations. To investigate the underlying processes at one such location-the Luquillo Experimental Forest in eastern Puerto Rico-66 days of detailed throughfall and above-canopy climatic data were collected in 1996 and analysed using the Rutter and Gash models of rainfall interception. Throughfall occurred on 80% of the days distributed over 80 rainfall events. Measured interception loss was 50% of gross precipitation. When Penman-Monteith based estimates for the wet canopy evaporation rate (0.11 mm h Ϫ1 on average) and a canopy storage of 1.15 mm were used, both models severely underestimated measured interception loss. A detailed analysis of four storms using the Rutter model showed that optimizing the model for the wet canopy evaporation component yielded much better results than increasing the canopy storage capacity. However, the Rutter model failed to properly estimate throughfall amounts during an exceptionally large event. The analytical model, on the other hand, was capable of representing interception during the extreme event, but once again optimizing wet canopy evaporation rates produced a much better fit than optimizing the canopy storage capacity. As such, the present results support the idea that it is primarily a high rate of evaporation from a wet canopy that is responsible for the observed high interception losses. ᭧ 1999 Elsevier Science B.V. All rights reserved.

The impact of forest regeneration on streamflow in 12 mesoscale humid tropical catchments

“…energy limited; Calder, 1998), and therefore the expected increases in ET a due to forest regrowth are not evident in the Q record. However, the interception evaporation component of ET a can be well in excess of PET, particularly on mountainous maritime islands (Schellekens et al, 1999;Roberts et al, 2005;Holwerda et al, 2006Holwerda et al, , 2012McJannet et al, 2007;Giambelluca et al, 2009). Moreover, an insignificant correlation was obtained between forest cover change and mean Q during the dry season (January-March; Q dry ), when PET is not expected to be a limiting factor (Fig.…”

Modelling and measurement of two-layer-canopy interception losses in a subtropical evergreen forest of central-south China

“…d and z 0 were estimated as 0.75 and 0.1, respectively, of the average stand height (Rutter et al, 1971(Rutter et al, , 1975. Evaporation rate (E) for the saturated canopy of a sparse forest can be estimated as E p when C≥S, or as E=E p ·C/S, when C<S (C is the actual canopy storage and S is canopy storage capacity) (Teklehaimonot and Jarvis, 1991;Domingo et al, 1998;Schellekens, et al, 1999). Rainfall intensity, R, is calculated for all hours when the rainfall exceeds the threshold, 0.5 mm (Gash et al, 1995).…”

Characteristics of rain events at an inland locality in northeastern Borneo, Malaysia

“…Based on the few reports available, the characteristics of tropical rain-events are thought to regulate the rate of wet-canopy evaporation (Lloyd, 1990;Asdak et al, 1998;Schellekens et al, 1999;Chappell et al, 2001), transpiration supression (Szarzynski and Anuf, 2001), shallow water-table fluctuations (Bidin et al, 1993), and runoff behaviour (Robinson and Sivapalan, 1997;Bonell et al, 2004). Many studies have also attributed the temporal variation in tropical geomorphic activity to rain-event characteristics, particularly those of large events Morgan, 2004).…”