Research finds discrepancies between satellite, global model estimates of land water storage

Research led by The University of Texas at Austin has found that calculations of water storage in many river basins from commonly used global computer models differ markedly from independent storage estimates from GRACE satellites.

The findings, published in the Proceedings of the National Academy of Sciences on Jan. 22, raise questions about global models that have been used in recent years to help assess water resources and potentially influence management decisions.

The study used measurements from GRACE satellites from 2002 to 2014 to determine water storage changes in 186 river basins around the world and compared the results with simulations made by seven commonly used models.

The GRACE satellites, operated by NASA and the German Aerospace Center, measure changes in the force of gravity across the Earth, a value influenced by changes in water storage in an area. The computer models used by government agencies and universities were developed to assess historical and/or scenario-based fluxes in the hydrological cycle, such as stream flow, evapotranspiration and storage changes, including soil moisture and groundwater.