A new probability density function for spatial distribution of soil water storage capacity leads to the SCS curve number method

Abstract. Following the Budyko framework, the soil wetting ratio (the ratio betweensoil wetting and precipitation) as a function of the soil storage index (theratio between soil wetting capacity and precipitation) is derived from theSoil Conservation Service Curve Number (SCS-CN) method and the variableinfiltration capacity (VIC) type of model. For the SCS-CN method, the soilwetting ratio approaches 1 when the soil storage index approaches ,due to the limitation of the SCS-CN method in which the initial soil moisturecondition is not explicitly represented. However, for the VIC type of model,the soil wetting ratio equals the soil storage index when the soil storageindex is lower than a certain value, due to the finite upper bound of thegeneralized Pareto distribution function of storage capacity. In this paper,a new distribution function, supported on a semi-infinite interval $x\in \left[\mathrm{0},\mathrm{\infty }\right)$, is proposed for describing the spatial distribution of storagecapacity. From this new distribution function, an equation is derived for therelationship between the soil wetting ratio and the storage index. In thederived equation, the soil wetting ratio approaches 0 as the storage indexapproaches 0; when the storage index tends more »

Authors:
Award ID(s):
Publication Date:
NSF-PAR ID:
10106188
Journal Name:
Hydrology and Earth System Sciences
Volume:
22
Issue:
12
Page Range or eLocation-ID:
6567 to 6578
ISSN:
1607-7938
National Science Foundation
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