A global dataset of average specific yield for soils

Abstract

Specific yield (Sy) stands as a critical parameter and a significant source of error in groundwater simulations. However, there is still a lack of reliable global Sy datasets. Based on the trilinear graph of Sy and soil textures, we develop a comprehensive global dataset of gridded average specific yield (GASY) aimed for various soil textures, which are obtained from the Global Soil Dataset for Earth System Models, the SoilGrids product, and the Harmonized World Soil Database. Validations with existing Sy values estimated by laboratory and field methods across different Sy concepts, at the aquifer-scale to global-scale, compellingly revealed that the GASY effectively represents reliable average Sy for each soil texture. The depth limitation (~2 m) of GASY is attributed to the depth limitations of soil texture data, and readers can expand the GASY into deeper soils by reasonably assuming a vertical variation of soil texture with depth. The GASY holds great benefits for future modeling of groundwater dynamics and understanding the groundwater resources distribution and mitigation of climate change impacts.