The availability of soil water retention data is essential for quantifying mass and energy exchange processes at the interface between land surface and atmosphere. In large-scale applications, soil water retention characteristics usually are estimated with empirical models that, unfortunately, use non-uniform predictors and were developed on subsets of the global distribution of soils. Their reliability for global estimates is often unknown. Using a global database, we developed an ensemble of up to thirteen previously published models allowing estimates of soil water retention data under data-poor to data-rich conditions. High-resolution global maps of key points in soil water retention characteristics (and their uncertainties) were produced. These maps suggest that middle and high latitudes in the Northern Hemisphere have larger variability of the estimates. The new model provides more accurate estimates than models currently being used in earth system models.
Recently, this work has been published by our faculty member Dr. Yonggen Zhang in Geophysical Research Letters. This work was supported by the National Natural Science Foundation of China (grant number: 41807181) and USDA-NIFA project W-3188. The code and global maps (in GeoTIFF format) of mean values and coefficients of variation of saturated moisture content, field capacity, and permanent wilting point estimated from overall 13-PTF ensemble model can be downloaded from https://doi.org/10.7910/DVN/VPIN2B.
Article information
Yonggen Zhang, Marcel G Schaap, Zhongwang Wei. Development of Hierarchical Ensemble Model and Estimates of Soil Water Retention with Global Coverage. Geophysical Research Letters. 2020, 47(15).
Website: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020GL088819
Figure. Global maps of mean values and coefficients of variation (CV) of saturated moisture content (a and b), moisture content at -0.33 bar (c and d), and -15 bar (e and f) in 10 km resolution from overall 13-PTF ensemble model for the surface layer. Calculations are based on the surface soil of the OpenLandMap 250 m resolution data but the maps are plotted in the center of the 10 km pixel.
