Submitted to: Water
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/14/2017
Publication Date: N/A
Citation: N/A Interpretive Summary: The Soil and Water Assessment Tool (SWAT) and Agricultural Policy EXtender (APEX) are widely used water quality models in the U.S. The climate data required by these models are very important but difficult and time-consuming for users to process. In this paper we describe the development of a U.S. climate database that can be used directly. These data are freely available on the web to support modeling studies in the U.S.
Technical Abstract: Water quality simulation models such as the Soil and Water Assessment Tool (SWAT) and Agricultural Policy EXtender (APEX) are widely used in the U.S. These models require large amounts of spatial and tabular data to simulate the natural world. Accurate and seamless daily climatic data are critical for accurate depiction of the hydrologic cycle, yet these data are among the most difficult to obtain and process. In this paper we describe the development of a national (U.S.) database of preprocessed climate data applicable to USGS 12-digit watersheds. Various sources and processing methods are explored and discussed. We find that surface station observations are preferred over spatially aggregated gridded climate sources. A relatively simple method was employed to choose representative stations for each of 83,000 12-digit watersheds in the continental U.S. These data are freely available online to facilitate other SWAT and APEX modeling efforts in the U.S.