A review of the Match technique as applied to AASE-2/EASOE and SOLVE/THESEO 2000

[摘要] We apply the NASA Goddard Trajectory Model to data from a series ofozonesondes to derive ozone loss rates in the lower stratosphere for theAASE-2/EASOE mission (January-March 1992) and for the SOLVE/THESEO 2000mission (January-March 2000) in an approach similar to Match. Ozone lossrates are computed by comparing the ozone concentrations provided byozonesondes launched at the beginning and end of the trajectories connectingthe launches. We investigate the sensitivity of the Match results to thevarious parameters used to reject potential matches in the original Matchtechnique. While these filters effectively eliminate from consideration80% of the matched sonde pairs and >99% of matched observations inour study, we conclude that only a filter based on potential vorticitychanges along the calculated back trajectories seems warranted. Our studyalso demonstrates that the ozone loss rates estimated in Match can vary byup to a factor of two depending upon the precise trajectory paths calculatedfor each trajectory. As a result, the statistical uncertainties publishedwith previous Match results might need to be augmented by an additionalsystematic error. The sensitivity to the trajectory path is particularlypronounced in the month of January, for which the largest ozone loss ratediscrepancies between photochemical models and Match are found. For most ofthe two study periods, our ozone loss rates agree with those previouslypublished. Notable exceptions are found for January 1992 at 475K and lateFebruary/early March 2000 at 450K, both periods during which we generallyfind smaller loss rates than the previous Match studies. Integrated ozoneloss rates estimated by Match in both of those years compare well with thosefound in numerous other studies and in a potential vorticity/potentialtemperature approach shown previously and in this paper. Finally, we suggestan alternate approach to Match using trajectory mapping. This approach usesinformation from all matched observations without filtering and uses atwo-parameter fit to the data to produce robust ozone loss rate estimates.As compared to loss rates from our version of Match, the trajectory mappingapproach produces generally smaller loss rates, frequently not statisticallysignificantly different from zero, calling into question the efficacy of theMatch approach.

[学科分类] 大气科学