Comparison of Wet-Deposition Data for Co-located Canadian Air and Precipitation Monitoring Network and National Atmospheric Deposition Program / National Trends Network Sites, 2005-2011

Daily Canadian Air and Precipitation Monitoring Network and weekly National Atmospheric Deposition Program / National Trends Network wet-deposition data collected continuously during 2005-2011 at two co-located sites located in Quebec, Canada and Pennsylvania, USA were compared statistically. Data analysis procedures used by Sirois et al. (2000) and Wetherbee et al. (2010) were used to estimate bias and variability between the two networks. Results indicate that the two network data sets continue to be compatible for continental scale studies. In general, CAPMoN values are higher than NADP values. It is speculated that these differences are due to differences in measurement protocols between the two networks. During 2005-2011, variability in co-located CAPMoN-minus-NADP concentration differences remained consistent for calcium, magnesium, sodium, potassium, ammonium, hydrogen-ion, sample depth, and precipitation depth. Variability decreased for chloride, nitrate, and sulfate after 2008.