Comparison between DC‐8 and ER‐2 species measurements in the tropical middle troposphere: NO, NOy, O3, CO2, CH4, and N2O

We compare measurements of six species taken aboard NASA DC‐8 and ER‐2 aircraft during two flight legs in the tropical middle troposphere near Hawaii. NO, NOy, O3, CH4, and N2O measurements agree to within the limits set by the known systematic errors. For CO2, which can be measured with better relative precision than the other five species, differences in measured values from the two platforms are slightly larger than expected if the air masses sampled by the two aircraft were indeed similar in CO2 composition to better than 0.08%.