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United States Department of Agriculture

Agricultural Research Service

Research Project: INTEGRATED ASSESSMENT AND ANALYSIS OF PHYSICAL LANDSCAPE PROCESSES THAT IMPACT THE QUALITY AND MANAGEMENT OF AGRICULTURAL WATERSHEDS Title: Comparisons of Historical versus Synthetic Weather Inputs to Watershed Models and their Effect on Pollutant Loads

Authors
item Theurer, F -
item Moore, D -
item Merkel, W -
item Quan, Q -
item Moody, H -
item Bingner, Ronald
item Bonta, James
item Flanagan, Dennis

Submitted to: Federal Interagency Sedimentation Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 24, 2010
Publication Date: June 27, 2010
Citation: Theurer, F.D., Moore, D.S., Merkel, W.H., Quan, Q.D., Moody, H.F., Bingner, R.L., Bonta, J.V., Flanagan, D.C. 2010. Comparisons of Historical versus Synthetic Weather Inputs to Watershed Models and their Effect on Pollutant Loads. In: Proceedings of the Federal Interagency Sedimentation Conference, June 27-July 1, 2010, Las Vegas, Nevada. 2010 CDROM.

Interpretive Summary: Synthetic weather generators are important for continuous-simulation of agricultural watersheds for risk analyses of downstream water quality. Many watersheds are sparsely or totally ungauged and daily weather must either be transposed or augmented. Since water quality models must recognize runoff, erosion, sediment transport, and pollutant loads, augmented precipitation statistics must reflect the precipitation patterns as well as the average annual precipitation of the indigenous parent’s historical climate. This paper addresses how well synthetic weather generators reproduce their original historical weather’s precipitation amounts and patterns that are to be used for subsequent simulation of watershed runoff, erosion, streamflow and pollutant loads. Synthetically generated climate can create time series of daily weather that are long enough to conduct risk analyses; i.e., frequency and probability analyses of the resulting streamflow and pollutant loads. Historical records frequently are serially incomplete and generally too short, or simply may not be available, for such purposes. Improvement in climate generation technology is needed to address the interaction of weather patterns over large watershed areas for effective evaluation of conservation practices.

Technical Abstract: Synthetic weather generators are important for continuous-simulation of agricultural watersheds for risk analyses of downstream water quality. Many watersheds are sparsely or totally ungauged and daily weather must either be transposed or augmented. Since water quality models must recognize runoff, erosion, sediment transport, and pollutant loads, augmented precipitation statistics must reflect the precipitation patterns as well as the average annual precipitation of the indigenous parent’s historical climate. This paper addresses how well synthetic weather generators reproduce their parent’s historical weather’s precipitation amounts and patterns which are to be used for subsequent simulation of watershed runoff, erosion, streamflow and pollutant loads. Synthetically generated climate can create time series of daily weather that are long enough to conduct risk analyses; i.e., frequency and probability analyses of the resulting streamflow and pollutant loads. Historical records frequently are serially incomplete and generally too short, or simply may not be available, for such purposes.

Last Modified: 12/18/2014
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