We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Global joint assimilation of GRACE and SMOS for improved estimation of root-zone soil moisture and vegetation response.
- Authors
Siyuan Tian; Renzullo, Luigi J.; Van Dijk, Albert I. J. M.; Tregoning, Paul; Walker, Jeffrey P.
- Abstract
The lack of direct measurement of root-zone soil moisture poses a challenge to the large-scale prediction of ecosystem response to variation in soil water. Microwave remote sensing capability is limited to measuring moisture content in the uppermost few centimetres of soil. In contrast, GRACE (Gravity Recovery and Climate Experiment) mission detected the variability in storage within the total water column, which is often dominated by groundwater variation. However, not all vegetation communities can access groundwater. In this study, satellite-derived water content from GRACE and SMOS were jointly assimilated into an ecohydrological model to better predict the impact of changes in root-zone soil moisture on vegetation vigour. Overall, the accuracy of root-zone soil moisture prediction though the joint assimilation of surface soil moisture and total water storage retrievals showed improved consistency with ground-based soil moisture measurements and satellite-observed greenness when compared to open-loop estimates (i.e. without assimilation). For example, the correlation between modelled and in-situ measurements of root-zone moisture increased by 0.1 on average over grasslands and croplands. Improved correlations were found between vegetation greenness and soil water storage derived from the joint assimilation with an increase up to 0.47 over grassland compared to open-loop estimates. Joint assimilation results show a more severe deficit in soil water in eastern Australia, western North America and eastern Brazil over the period of 2010 to 2015 than the open-loop, consistent with the satellite-observed vegetation greenness. The assimilation of satellite-observed water content contributes to more accurate knowledge of soil water availability, providing new insights for monitoring hidden water stress and vegetation response.
- Subjects
SOIL moisture measurement; VEGETATION monitoring; REMOTE sensing
- Publication
Hydrology & Earth System Sciences Discussions, 2018, p1
- ISSN
1812-2108
- Publication type
Abstract
- DOI
10.5194/hess-2018-442