WXGN is the model used in EPIC (Erosion/Productivity Impact Calculator) and APEX (Agricultural Policy/Environmental eXtender Model) (Sharpley & Williams 1990a,b) for generating daily weather variables. It is based on the weather data generator developed by Richardson (1981) and Richardson & Wright (1984). WXGN uses standard deviation instead of skew coefficient for temperature generation; this eliminates erroneous values generated in areas where the mean monthly temperature is at or near zero. WXGN does use precipitation skew coefficient. Skew coefficient is precipitation’s third standardized moment calculated from the third central moment divided by the cube of the standard deviation. The release of WXGN is restricted to those researchers and individuals working with the modeling team to enhance scientific understanding or application of the model. We encourage those with interest or modification of the model to contact us email@example.com.
WXGN License Agreement