From Coarse Resolution to Realistic Resolution: GRACE as a Science Communication and Policymaking Tool for Sustainable Groundwater Management
Authors: Xu Li , Famiglietti James S. , Ferris David , Huggins Xander , Mohan Chinchu , Sadri Sara , Sanyal Palash , Wong Jefferson S. 
Published: March 2022

&lt;p&gt;Managing groundwater resources is challenging because they are difficult to monitor. The application of remote sensing methods has improved our capacity to monitor variability in groundwater storage, as is the case for the Gravity Recovery and Climate Experiment (GRACE) and the GRACE Follow-On (GRACE-FO) missions. While GRACE-based groundwater studies to date have covered many places across the globe, perspectives that link scientific studies to policymaking and practices are still limited. Challenges to applying GRACE data into practice result from their coarse resolution, which limits their utility at the smaller scales at which water management decisions are made. Another reason is that the data and related studies can be difficult to use and understand by policymakers and end-users. However, these challenges offer the GRACE scientific community opportunities to communicate with stakeholders, policymakers, and the public in raising awareness around groundwater sustainability issues. This paper addresses three questions: which GRACE data and GRACE-derived products can be useful for groundwater practices and management; how GRACE-derived groundwater messages can be better communicated with practitioners; and how to better operationalize GRACE-derived products for groundwater practice and management. This paper also aims to provide an agenda for the continued use of GRACE and GRACE-FO for the purpose of sustainable groundwater management. To gain insight into these questions, a policy Delphi survey was conducted to collect opinions of both the scientific and non-scientific communities. We made use of target search and snowballing techniques to identify suitable participants who are experienced groundwater researchers or practitioners, and who are familiar with GRACE. A total of 25 participants from around the world were surveyed (14 scientific and 11 non-scientific), and they provided thoughtful responses. We found that both communities acknowledged the potential of GRACE data and GRACE-derived products for groundwater management, and would be willing to collaborate to develop projects for practical applications. Better communication between researchers and practitioners was recommended as a key for the application of GRACE-derived products into practice. Practitioners noted their high demand for reliable data for their management responsibilities, but are more favorable towards locally observed data. The reliability of GRACE at small scales was an issue, even though some robust downscaling methods have been demonstrated down to local scales. The survey showed a desire for more comparison of GRACE-derived products to local measurements to determine whether GRACE products, e.g. downscaled data, can be useful for informing local decisions. Based on the survey, we proposed an agenda that helps to improve the usefulness of GRACE-derived products for practices. This agenda includes scientific recommendations that help to resolve the resolution and technical barriers for local applications, and professional perspectives that bridge the connection between science and policy, and facilitate communication for groundwater management.&lt;/p&gt;