Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 8/11/2020
Publication Date: 9/3/2020
Citation: Van Donk, S., Tatarko, J., Skidmore, E.L., Wagner, L.E., Fox, F.A. 2020. Weather generators of WEPS. In: Tatarko, J. (ed). Wind Erosion Prediction System (WEPS): Technical Documentation. Book Chapter. Agricultural Handbook 727.
Technical Abstract: The Wind Erosion Prediction System (WEPS) requires specific weather data in order to simulate the processes governing soil erosion by wind. The WEPS weather generators simulate the needed weather data through two separate computer weather models. CLIGEN is a stochastic generator of climate (weather) data, simulating daily estimates of precipitation (amount, duration, peak intensity), temperature (maximum, minimum, dewpoint), wind (direction and speed), and solar radiation. It generates these for a single geographic point, using monthly statistical parameters (means, standard deviations, skewness, etc.) derived from historic measurements. Wind is the principal driver of WEPS simulation of wind-blown sediment loss from a field. The wind parameters in CLIGEN are not adequate for WEPS and so the WINDGEN model was created to provide wind parameters needed by the WEPs model. Similar to CLIGEN, WINDGEN is a stochastic wind generator for WEPS that uses monthly parameters derived from historic measurements to generate wind, providing the unique requirements of hourly wind speeds and daily wind direction for each day of simulation. Since WINDGEN bases its generations on historical statistics of wind, it reflects the past wind histories at a given location. Station parameter files (summary statistics) to run both generators are available for several thousand U.S. locations. Details of the methods by which the weather generators simulate the required weather parameters are described in this document.