Assimilating surface soil moisture to estimate profile soil water content using EnKF and Hydrus-ID Model

摘要

Soil moisture status in the root zone is an important component of the water cycle. The numerical one-dimensional vadose zone hydrology model (HYDRUS-ID) is widely used to depict the distribution of soil moisture in the root zone. The primary objective of this study is to investigate the performance of updating soil profile water content by assimilating the surface soil moisture into the HYDRUS-ID model at point scale using the ensemble Kalman filter (EnKF) technique. The results indicate that, surface soil moisture estimation can be improved significantly by using a data assimilation method when there is precipitation, but no improvement is achieved when there is no precipitation; in deep layers, the soil moisture does not vary significantly with time and therefore the effect of assimilation is limited.