Fig. 4: Comparisons of NO2 spectral retrieval results from orbit 03241 on 17 December 2018.

a The current EMI NO2 retrieval in Table 1. b same as in a but using solar reference. c same as in a, but without spectral precalibration. The resulting NO2 SCD, relative uncertainty, and RMS of the fitting residual are shown in the upper, middle, and bottom panels, respectively. The fitted NO2 SCD and its uncertainty are masked in the white color when RMS > 0.004