Fig. 4: Uncertainties with sub-sampling for nitrate-nitrogen.
From: High flows contributed a large part of annual contaminant yields in New Zealand’s rivers
Absolute percentage difference between nitrate-nitrogen (NO3-N) yields estimated by different sampling frequencies (2-hourly, 6-hourly, 12-hourly, daily, weekly, and monthly) and the ‘true’ yields (calculated from high-frequency data), for high flow yields (top graph) and total (All flows) yields (bottom graph) The different number of samples reflect variation in flow at each site.
