Global Changes in Stratospheric Composition: Aura MLS and Past Measurements versus Models

Wednesday, 17 December 2014: 11:20 AM
Lucien Froidevaux1, Douglas Edward Kinnison2, Ryan A Fuller1, John Anderson3, Hsiang-Jui Wang4, Hugh C Pumphrey5, Peter F Bernath6 and Nathaniel J Livesey1, (1)Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, United States, (2)National Center for Atmospheric Research, Boulder, CO, United States, (3)Hampton University, Hampton, VA, United States, (4)Georgia Tech, Atlanta, GA, United States, (5)University of Edinburgh, Edinburgh, United Kingdom, (6)Old Dominion University, Norfolk, VA, United States
Aura MLS atmospheric measurements have now been obtained near-globally and continuously on a daily basis for 10 years. We place some of the stratospheric composition measurements in perspective, by using merged datasets that include the Aura MLS data. Global monthly zonal mean stratospheric data records from satellite-based remote measurements were created by NASA's Global Ozone Chemistry and Related Trace gas Data Records for the Stratosphere (GOZCARDS) project. These data records were drawn from high quality satellite-based measurements of stratospheric composition starting in 1979 for ozone and in the early 1990s for other data records. Merged data records were obtained by combining the instrument-specific (source) data records, taking into account the mean biases between them during time periods of overlap. We briefly review the construction of GOZCARDS merged data records and provide observational results for various species (HCl, H2O, O3, N2O, HNO3). We use two model versions of the Whole Atmosphere Community Climate Model (WACCM), a free-running (FR-WACCM) and a "specified dynamics" (SD-WACCM) version, to highlight differences in the level of agreement between the models and the observations.