Fig. 4
From: Year-round trace gas measurements in the central Arctic during the MOSAiC expedition
Cross-evaluation of redundant measurements. Comparison of minute-averaged (a) CO2, (b) CH4, (c) CO and (d) N2O mole fractions measured in the University of Colorado (CU), Swiss, and Atmosphere Radiation Measurement (ARM) Program containers against atmospheric abundances inferred from discrete whole air sampling for post-cruise analysis at NOAA Global Monitoring Laboratory (used as calibration reference). (e) Comparison of minute-averaged O3 mole fractions measured in the CU and Swiss containers against mole fractions measured in the ARM container (used as calibration reference). Shaded and solid contours show initial and adjusted (after cross-evaluation) values, respectively. The shape of the density distributions may change due to the use of time-dependent correction factors. Vertical dashed and solid lines show the median relative difference to the reference for initial and adjusted values, respectively. Note that the ARM N2O time series was not adjusted for calibration bias as we did not generate a merged N2O dataset. The kernel density estimates (smoothed version of a histogram) were computed using R package ggplot2 (version 3.3.3).
