GEWEX SoilWat Initiative

The GEWEX-ISMC* SoilWat Initiative brings together two research communities to improve the representation of soil and subsurface processes in climate models. The soil and groundwater community and the climate modeling community (the latter represented by GEWEX) are working together to identify the most pressing challenges and topics related to this effort.

Participants identified three main initiatives at the 1st GEWEX SoilWat Initiative Planning Workshop held in June 2016. A report on the workshop detailing discussions and outcomes is available here.
The first initiative is a joint GEWEX and International Soil Modeling Consortium (ISMC) project to conduct an in-depth survey on how key soil physical processes (related to water and heat flow) are represented in Land Surface Models (LSMs). The second initiative is a systematic assessment of the utility of resolved soil maps and sensitivity of climate models in improving the quality and resolution of soil maps. The third initiative involves conducting a survey of how groundwater is implemented in climate models and define strategies for better incorporation of groundwater in climate models. These initiatives are intended to lead to the creation of a global database of historical and current groundwater levels.
Ongoing and completed activities related to the three initiatives include:

  • An overview of pedotransfer functions (PTFs) that are used in LSMs (and other) models; model sensitivity analyses related to the choice of PFTs.
  • Surveys of existing process equations in LSMs (such as infiltration and soil evaporation).
  • Preparation of global soil physical (hydraulic and thermal) parameter sets.
  • Preparation of global LSM soil-related verification data sets (e.g., on infiltration).
  • Carrying out Model Intercomparison Studies that look at the separate effects of texture information, PFT and soil hydraulic parameter choice.
  • A white paper on “global groundwater modeling and monitoring: Opportunities and challenges”.

The GEWEX SoilWat Initiative welcomes collaboration. If you are interested in any of these efforts, please contact the International GEWEX Project Office at or one of the organizers Yijian Zeng (GLASS panel representative), Anne Verhoef (thermal properties), Dani Or (soil evaporation/hydraulic properties), Matthias Cuntz (SPMIP), Lukas Gudmundsson (SPMIP), Lutz Weihermueller (PTFs/hydraulic properties), Stefan Kollet (groundwater) and Harry Vereecken (PTFs/hydraulic properties, infiltration) directly.

*International Soil Modelling Consortium