Here is a plot of the vertical column densities of NO2 and O3 from an ultraviolet-visible spectrometer in Fairbanks, Alaska. It is interesting to see that when NO2 dips, O3 rises, and vice versa. Also, because the scale of both the graphs is so different, I cannot plot them together, which makes it difficult to see if the dips in both the plots is occurring simultaneously. This is important to verify the fact that is the instrument compromised by any kind of artefact or not. I was thinking of doing a dy/dx (where y=NO2 and x=O3) to see if the sign is the same, meaning that both the measurements are following the same pattern. Otherwise, the general trend of both the measurements is supposed to be opposite. Is this a good way to check my hypothesis?