![Sample our Environment & Sustainability journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5935/TOC-Subject-Sample-2021-Environment-Sustainability.jpg"})
The Erosion/Productivity Impact Calculator (EPIC) is a widely used agricultural model for assessing potential soil erosion and the impact of soil loss on crops. An essential input to the model is a daily record of weather variables, and this is obtained by simulation in a stochastic “weather generator” (WXGEN). This study ascertains if the weather generated by WXGEN is realistic, and puts test results into the context of input requirements of other component models of EPIC.
Five strategically located Texas first‐order stations were chosen for comprehensive testing, and ten 30‐year sequences of weather were generated for each site using data incorporated into the model as parameters. A range of statistics were extracted from these, and were compared with similar statistics obtained from observed 1958–87 records.
More than 20,000 statistical tests were carried out, each with a null hypothesis of similarity. For almost every series of tests at the 0.05 level of significance, over 15% fell into the rejection region, indicating that sequences of weather generated by WXGEN are often unrealistic. This undoubtedly affects the accuracy of soil erosion and crop productivity predictions made by EPIC.