Overview of the validation of POAM III version 4 retrievals

A statistical analyses of comparisons between POAM III version 4.0 retrievals and measurements from HALOE (version 19) and SAGE II (version 6.2) and ozonesondes have been performed. In addition, when available, limited numbers of comparisons with aircraft-based instruments have been performed. For statistical analyses with correlative satellite data, coincidence criteria were 500 km and 2 hours unless too few coincidences were found, in which case the time criterion was relaxed to 12 hours. Comparisons for NO2, however, included only measurements that occurred within 2 hours to avoid artifacts due to diurnal variations. Coincident measurements for satellite statistical analyses were also required to occur within 3 degrees in equivalent latitude.