Precipitation Chemistry Quality Assurance Project (PCQA)

Special Studies and Field Activities

Please note: Special Studies data, analysis, and interpretation are preliminary and subject to revision. These results have not been peer reviewed for publication, but they are provided herein to help NADP data users understand various characteristics and limitations of NADP data. The USGS External Quality Assurance Program for the NADP has determined that these studies are important, but not worthy of publication in peer reviewed journals or U.S. government reports. These results have been presented in NADP business meetings and technical symposia, and the presentations are documented in NADP meeting minutes.

For citation purposes, the following in-text reference is suggested:
Greg Wetherbee, U.S. Geological Survey, written communication, date, URL.

• AeroChem / N-CON Collector Comparison



• Arvada, Colorado-Urban Site Instrument Photographs



• Belfort / OTT Rain Gage Comparison for Snow Measurement



• Isopleth Maps Generated Using PRISM Precipitation Estimates



• Sample Evaporation Study



• Weather Does Not Affect Measurement Error



• Historical / Discontinued QA Programs



• NTN 2006 Blind Audit of CAL Detection Limits



• Urbanization of NADP/NTN Sites