Solar occultation satellite data and derived meteorological products: Sampling issues and comparisons with Aura microwave limb sounder

Derived Meteorological Products (DMPs, including potential temperature, potential Vorticity (PV), equivalent latitude (EqL), horizontal winds and tropopause locations) from several meteorological analyses have been produced for the locations and times of measurements taken by several solar occultation instruments and the Aura Microwave Limb Sounder (MLS). MLS and solar occultation data are analyzed using DMps to illustrate sampling issues that may affect interpretation and comparison of data sets with diverse sampling patterns and to provide guidance regarding the kinds of studies that benefit most from analyzing satellite data in relation to meteorological conditions using the DMPs. Using EqL or PV as a vortex-centered coordinate does not alleviate all sampling problems, including those in studies using "vortex averages" of solar occultation data and in analyses of localized features (such as polar stratospheric clouds) and other fields that do not correlate well with PV. Using DMPs to view measurements with respect to their air mass characteristics is particularly valuable in studies of transport of long-lived trace gases, polar processing in the winter lower stratosphere, and distributions and transport Of O₃ and other trace gases from the upper troposphere through the lower stratosphere. The comparisons shown here demonstrate good agreement between MLS and solar occultation data for O₃, N₂O, H₂O, HNO₃, and HCl; small biases are attributable to sampling effects or are consistent with detailed validation results presented elsewhere in this special section. The DMPs are valuable many scientific studies and to facilitate validation of noncoincident measurements.