Influence of temporal variability of rainfall on interception loss. Part I. Point analysis

An interception model that Links the temporal variability of rainfall with the storm-based description of the interception process is derived. Analyti cal formulae for long-term interception loss are obtained for precipitation with statistical characteristics derived from observations. The analysis of the results indicates that the point interception loss is c ontrolled primarily by three time scales: the mean inter-storm arrival time tau(a), the mean storm duration tau(n), and the time to evaporate a satura ted canopy tau(r), which depends on canopy water holding capacity W-e and t he wet canopy potential evaporation rate E-10,. and less importantly, on st orm intensity. Additional assumption of rainfall stationarity lends to a re lation between long-term interception loss and gross rainfall that requires a very small amount of input data. The interception loss predicted by the analytical model agrees well with th at of a Rutter model driven by a synthetic rainfall time series with the sa me statistics. Using the parameter values estimated from the observed rainf all data in the Amazon and southwestern France, the analytical results pred ict a long-term interception loss close to that observed. (C) 2000 Elsevier Science B.V. All rights reserved.