Figure 1.
Probability of detection (POD) versus emission rate (kg CH4/h) for point sensor network solutions (A,D,F) and a scanning/imagine solution (B) fitted using power functions. The x-axis is divided into equal-sized bins, with each marker (pod) as the fraction of controlled releases in a bin classified as true positives. Data points from the study by Bell et al. (2022) are overlaid on the current results for comparison. Emission rate at which the POD reaches 90% is indicated as the method detection limit (DL90) for each solution. Each pod data point is bootstrapped to produce a cloud of curves illustrating the associated uncertainty. When the bootstrapping could not evaluate the lower and upper empirical confidence limit (CL) on a solution’s DL90 best estimate, they are given as 0 and NA, respectively. Curve fits (dotted colored lines) obtained using other quantile-based discretizations are shown for comparison. DL90s of 3 of the 4 solutions (B,D,F) in the current study were within the tested emission rate range. Mean count of points per bin, along with the min and max counts across all bins, is also shown in the figure.