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ARS Home » Pacific West Area » Boise, Idaho » Northwest Watershed Research Center » Research » Publications at this Location » Publication #150154
Title: THE DUAL-GAUGE SYSTEM FOR MEASURING PRECIPITATION: HISTORICAL DEVELOPMENT AND USE

Author
item HANSON, CLAYTON - RETIRED ARS
item Pierson Jr, Frederick
item JOHNSON, GREGORY - USDA-NCRS

Submitted to: Journal Hydrologic Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/11/2004
Publication Date: 9/20/2004
Citation: Hanson, Clayton L, M.ASCE, Pierson, Frederick B., and Johnson, Gregory L., Journal of Hydrologic Engineering; Dual-gauge system for measuring precipitation: historical development and use, abstract, vol. 9, no. 5, 2004.

Interpretive Summary: Because precipitation is the primary component of the hydrologic cycle, it is imperative that the most accurate precipitation data are available for hydrologic and natural resource investigations. Undercatch of precipitation, due primarily to wind, is especially pronounced when measuring snowfall by gauges that are not naturally protected. The dual-gauge system that was developed at the Northwest Watershed Research Center can be used to measure all types of precipitation, but was designed specifically to improve the measurement of snowfall under windy conditions. The dual-gauge system uses sets of unshielded and shielded gauge data and an appropriate value of a calibration coefficient in an equation to calculate wind-adjusted precipitation. Data from field studies at the Reynolds Creek Experimental Watershed in SW Idaho and other sites in the United States, Canada, and Russia show that 1.8 is the most reasonable value to use for the calibration coefficient and that the dual-gauge system also significantly improves the measurement of other forms of precipitation. These studies also have led to the development of procedures for estimating wind-adjusted precipitation when only single unshielded or shielded gauge data are available.

Technical Abstract: Undercatch of precipitation, due primarily to wind, is especially pronounced when measuring snowfall by gauges that are not naturally protected, such as in brush or forest clearings. The dual-gauge system can be used to measure all types of precipitation, but was designed specifically to improve the measurement of snowfall under windy conditions. The dual-gauge system uses sets of unshielded and shielded gauge data and an appropriate value of a calibration coefficient in an equation to calculate wind-adjusted precipitation. After three winter seasons of field studies in Idaho, it was determined that 1.8 was the most appropriate value for the calibration coefficient. Analyses of data from other sites in the United States, Canada, and Russia also show that 1.8 is the most reasonable value to use for the calibration coefficient when calculating wind-adjusted snowfall amounts, and that the dual-gauge system also significantly improves the measurement of other forms of precipitation. These studies also have led to the development of procedures for estimating wind-adjusted precipitation when only single unshielded or shielded gauge data are available.