Characteristics of precipitation and the process of interception in a seasonally dry tropical forest

Abstract

Study region: Iguatu Experimental Basin, located in the semi-arid region of northeastern Brazil. Study focus: The aim of this study was to investigate the influence of rainfall characteristics on throughfall, stemflow and interception loss in a deciduous forest of a tropical semi-arid region, from a data series of eight consecutive years. The data were collected from 2010 to 2017, comprising a total of 225 events. New hydrological insights for the region: Among the variables used to characterize rainfall, the maximum 30-min intensity (I30) best explained the interception losses, which is also well correlated to rainfall depth and event average intensity. The predominant events (67% of the total) are characterised by low rainfall depth, low I30 and higher interception loss (18% of the gross rainfall). In addition, there is a threshold between rainfall characteristics and the interception process: for rainfall and I30 lower than 20 mm and 15 mm/h respectively, and rainfall duration lower than 100 min, interception losses are usually higher than 30%, reaching up to 74%. For the remaining events, interception losses are mostly within the range of 10–20% of rainfall. The data and information on the interception process, presented in this study, helps the comprehension of the overall water balance in dry environments and improve the capacity for parameterization of hydrological models, contributing to a more efficient water and environmental management. Keywords: Rainfall classification, Rainfall characteristics, Throughfall, Stemflow, Semi-arid region