Intercomparison of satellite and aircraft observations of ozone, CFC-11, and NO_y using trajectory mapping

The Cryogenic Infrared Spectrometers and Telescopes for the Atmosphere (CRISTA) satellite measured global distributions of over 15 trace constituents at high horizontal resolution (<500 km). The CRISTA mission began shortly before the end of the Airborne Southern Hemisphere Ozone Experiment and Measurements to Assess the Effects of Stratospheric Aircraft (ASHOE/MAESA) airborne measurement campaign. CRISTA measurements of ozone, CFC-11, and HNO₃ are available below 20 km, in the altitude range sampled by the ER-2 aircraft during ASHOE/MAESA. However, the time separation between the two missions makes a direct comparison of the data impossible. In this study, trajectory techniques are used to compare CRISTA measurements of ozone, CFC-11, and HNO₃ with ER-2 measurements taken during the last two flights of ASHOE/ MAESA on November 2 and 4, 1994. Visual comparison of CRISTA and ER-2 data from the November 4 flight is generally good. Mean tracer gradients across scales of ∼1000 km, as well as absolute mixing ratios agree well with those measured from the ER-2. Correlation coefficients for coincident pairs of ER-2 and CRISTA measurements are between 0.68 and 0.80. The comparison for the November 2 flight is poor. We argue that the poor agreement for this flight maybe due to both smaller CRISTA measurement density as well as rapid stretching in the air mass sampled by the ER-2 on November 2.