A procedure to estimate cover coefficient and parameters of soil moisture stress function using soil moisture monitoring data
Journal
Paddy and Water Environment
Journal Volume
11
Journal Issue
1-4
Pages
255-264
Date Issued
2013
Author(s)
Abstract
A procedure to determine soil moisture threshold (θ*), cover coefficient (kc), and parameters of soil moisture stress function (ks) is proposed in this study. These coefficients can be further applied to estimate daily actual evapotranspiration in a hydrological model. Two soil moisture stress functions are used to describe ks. One of the functions is proposed by this study, which assumes moisture stress is inversely proportional to matric potential described by van Genuchten retention curve. The procedure is applied to identify the coefficients for three kinds of reference potential evapotranspiration based on soil moisture monitoring. Soil moisture was measured by Watermark soil moisture sensors. These sensors were tested in a laboratory to establish the relationship between soil moisture and recorded tensor. Then, these sensors were installed in an experimental forest watershed. The verification study shows that the calibrated coefficients can provide reasonable estimate of actual evapotranspiration. The R2 = 0. 85 for using the Penman-Montieth equation for tall maize along with kc = 1. 81 can be obtained for the validation period with soil moisture stress. Besides, the results also indicate the proposed soil moisture stress function can have better performance on estimating daily actual evapotranspiration at early stage of a dry period. The proposed procedure and soil moisture stress functions can be successfully applied to estimate daily evapotranspiration when soil moisture is known. However, their performance in a hydrological model requires further study, since a hydrological model can only provide estimated soil moisture. © 2012 Springer-Verlag.
Subjects
Cover coefficient; Evapotranspiration; Penman-Monteith; Soil moisture stress; Watermark
SDGs
Other Subjects
Climate models; Evapotranspiration; Forestry; Functions; Hydrology; Microwave measurement; Moisture control; Stresses; Watermarking; Actual evapotranspiration; Cover coefficient; Daily actual evapotranspirations; Daily evapotranspirations; Penman Monteith; Potential evapotranspiration; Soil moisture monitoring; Soil moisture sensors; Soil moisture; Climates; Evaporation; Forestry; Hydrology; Microwaves; Moisture; Sensors; Soil; Transpiration; Water Marks; Water Supply; Zea mays
Type
journal article