HR: 17:15h
 AN: A54B-06    [Abstracts]
 TI: Using the Longitudinal Structure in Ozone Trends to Differentiate Between Chemical and Dynamical Forcing of Ozone
 AU: * Hassler, B
 AF: Meteorological Institute, University of Munich, Munich, 80799, Germany
AU: Bodeker, G E
 AF: National Institute of Water and Atmospheric Research, SH 85, Lauder, 9352, New Zealand
AU: Dameris, M
 AF: DLR, Institute for Physics of the Atmosphere, Oberpfaffenhofen, 82234, Germany
AU: Steinbrecht, W
 AF: Meteorological Observatory, German Weather Service, Hohenpeissenberg, 82383, Germany
AB: A new collection of high vertical resolution trace gas profiles, with global coverage, has been assembled. The collection includes measurements from different satellite (HALOE, POAM II and III, SAGE I and II) and ground- based measurement systems (ozonesondes, lidar). In addition to the primary products of temperature and ozone, secondary measurements of aerosol extinction, NO2 and H2O are included. All data products are subjected to very strict quality standards and for every measurement an error estimate is stored. To facilitate analyses, three different databases within the collection have been constructed, viz., measurements indexed by:

  1. geographic latitude, longitude, altitude (in 1 km steps) and time,
  2. geographic latitude, longitude, pressure (at levels ~1 km apart) and time,
  3. equivalent latitude, isentropic levels (8 levels from 300K to 650K) and time.
Global trends in the vertical distribution of ozone are traditionally calculated as a function of latitude and altitude. The improved spatial coverage achieved by combining measurements from a number of sources, as has been done here, permits the calculation of trends also within different longitude sections. Since chemical forcing of ozone trends is expected to be longitudinally independent, structure in trends by longitude are indicative of dynamical contributions to ozone changes. To calculate the required trends in ozone, a linear least-square regression model has been applied to time series of ozone, extracted from the 1st and 2nd databases described above, as a function of latitude, longitude and altitude. Trends in the regression model are calculated from a basis function based on equivalent effective stratospheric chlorine (EESC). Additional basis functions cover most known sources of stratospheric ozone variability, such as the QBO, solar cycle, volcanoes, and an annual cycle. The inclusion of other proxies (e.g. vortex strength, tropopause height) has also been investigated. In addition to the calculation of trends in ozone, this data base is expected to be suitable for a range of other applications such as assessment of chemistry-climate models and the calculation changes in radiative forcing from changes in ozone. Acknowledgements: We want to thank all institutions and colleagues who provided us with data for the database: NASA, NRL, WOUDC, NOAA, NDACC, H. Claude, Larry W. Thomason and all the people involved in the measurements and processing of the data. B. Hassler's work was funded by a DAAD studentship.
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
 DE: 3399 General or miscellaneous
 DE: 4215 Climate and interannual variability (1616, 1635, 3305, 3309, 4513)
 SC: Atmospheric Sciences [A]
 MN: 2007 Fall Meeting