Non-coincident inter-instrument comparisons of ozone measurements using quasi-conservative coordinates

Ozone measurements from ozonesondes, ARO- TAL, DIAL, and POAM III instruments during the SOLVE- 2/VINTERSOL period are composited in a time-varying, flow-following quasi-conservative (PV- ) coordinate space; the resulting composites from each instrument are mapped onto the other instruments' locations and times. The mapped data are then used to intercompare data from the different in- struments. Overall, the four ozone data sets are found to be in good agreement. AROTAL shows somewhat lower values below 16 km, and DIAL has a positive bias at the upper limits of its altitude range. These intercomparisons are consistent with those obtained from more conventional near-coincident profiles, where available. Although the PV- mapping tech- nique entails larger uncertainties of individual profile differ- ences compared to direct near-coincident comparisons, the ability to include much larger numbers of comparisons can make this technique advantageous.