The use of model-derived and observed precipitation in long-term sulfur concentration and deposition modeling

Using NGM precipitation does not significantly affect the results for the 1989 study period. Although the NGM does overpredict the precipitation during the summer months along the Gulf states, thereby increasing slightly the SO42− wet deposition and further underpredicting the modeled SO42− air concentration, the differences are small enough to suggest that the use of model-forecast precipitation can be an adequate substitute for precipitation observations over a seasonal or longer period.