Open-File Report 2011–1170
Selected aspects of National Atmospheric Deposition Program / National Trends Network (NADP/NTN) protocols are evaluated in four studies. Meteorological conditions have minor impacts on the error in NADP/NTN sampling. Efficiency of frozen precipitation sample collection is lower than for liquid precipitation samples. Variability of NTN measurements is higher for relatively low-intensity deposition of frozen precipitation than for higher-intensity deposition of liquid precipitation. Urbanization of the landscape surrounding NADP/NTN sites is not affecting trends in wet-deposition chemistry data to a measureable degree. Five NADP siting criteria intended to preserve wet-deposition sample integrity have varying degrees of effectiveness. NADP siting criteria for objects within the 90° cones and trees within the 120° cones projected from the collector bucket to sky are important for protecting sample integrity. Tall vegetation, fences, and other objects located within 5 meters of the collectors are related to the frequency of visible sample contamination, indicating the importance of these factors in NADP siting criteria.
First posted September 19, 2011
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Wetherbee, G.A., Latysh, N.E., Lehmann, C.M.B., and Rhodes, M.F., 2011, Four studies on effects of environmental factors on the quality of National Atmospheric Deposition Program measurements: U.S. Geological Survey Open-File Report 2011–1170, 36 p.
Meteorological Effects on Measurement Error
Precipitation Intensity Effects on NTN Samples
Site Urbanization Effects on NTN Trends
Relations of Site Characteristics to Sample Integrity