HR: 11:50h
AN: A22A-06    [Abstracts]
TI: Indicators of Antarctic ozone depletion: past and future
AU: * Bodeker, G E
EM: g.bodeker@niwa.co.nz
AF: National Institute of Water and Atmospheric Research, Private Bag 50061, Omakau, CO 9182 New Zealand
AU: Struthers, H
EM: h.struthers@niwa.co.nz
AF: National Institute of Water and Atmospheric Research, Private Bag 50061, Omakau, CO 9182 New Zealand
AU: Eyring, V
EM: Veronika.Eyring@dlr.de
AF: DLR-Institut für Physik der Atmosphäre, Oberpfaffenhofen D-82234 Wessling, Oberpfaffenhofen, D-82234 Germany
AU: Butchart, N
EM: neal.butchart@metoffice.com
AF: UK Met Office, FitzRoy Road Exeter, Devon, Exeter, EX1 3PB United Kingdom
AU: Shiona, H
EM: h.shiona@niwa.co.nz
AF: National Institute of Water and Atmospheric Research, Private Bag 50061, Omakau, CO 9182 New Zealand
AU: Smale, D
EM: d.smale@niwa.co.nz
AF: National Institute of Water and Atmospheric Research, Private Bag 50061, Omakau, CO 9182 New Zealand
AU: Austin, J
EM: John.Austin@noaa.gov
AF: NOAA Geophysical Fluid Dynamics Laboratory, Princeton Forrestal Campus Rte.1, 201 Forrestal Rd., Princeton, NJ NJ 08542-0 United States
AU: Dameris, M
EM: martin.dameris@dlr.de
AF: DLR-Institut für Physik der Atmosphäre, Oberpfaffenhofen D-82234 Wessling, Oberpfaffenhofen, D-82234 Germany
AB: A set of indicators describing the salient features of the Antarctic ozone hole has been developed, including:
1) daily measures of the area over Antarctica where ozone levels are below 150 DU, below 220 DU, more than 30% below 1979 to 1981 norms, and more than 50% below 1979 to 1981 norms,
2) the date of disappearance of 150 DU ozone values, 220 DU ozone values, values 30% below 1979 to 1981 norms, and values 50% below 1979 to 1981 norms, for each year,
3) daily minimum total column ozone values over Antarctica, and
4) daily values of the ozone mass deficit based on a O_3<220 DU threshold. To describe changes in the behavior of the Antarctic ozone hole over the period 1979 to 2005, these indicators have been calculated from an assimilated data base of total column ozone measurements made by 4 Total Ozone Mapping Spectrometer (TOMS) instruments, 3 different ozone retrievals from the Global Ozone Monitoring Experiment (GOME), 4 Solar Backscatter Ultraviolet (SBUV) instruments, and the Ozone Monitoring Instrument (OMI) flown onboard AURA. Intercomparisons between these satellite based measurements and the global network of Dobson spectrophotometers and Brewer instruments are used to remove offsets and drifts in the satellite data to create a single homogeneous data base. Projections of these indices for the coming decades have been calculated from global ozone fields from a number of chemistry-climate models (CCMs) participating in the SPARC (Stratospheric Processes And their Role in Climate) sponsored CCMVal activity. These projections can be used to identify which of the indices may be best suited as indicators of Antarctic ozone hole recovery. In a preliminary analysis based on ozone profiles from a 1975-2019 run of the UMETRAC (Unified Model with Eulerian Transport And Chemistry) CCM, monthly, seasonal and annual averages of partial ozone columns over 4 altitude ranges 100-200 hPa, 50-100 hPa, 10-50 hPa and 50-150 hPa), and over 4 latitude ranges (60°-70°S, 70°-80°S, 80°-90°S and 60°-90°S) have been calculated and examined for which most clearly signals a change in trend. It was found that the region showing the largest change in trend was November mean partial columns from 50-150 hPa between 60°S and 70°S. We will extend this analysis to additional CCM run results available through CCMVal, and subject the model output to more robust statistical analyses of the change in trends (Reinsel et al., 2002), to see if this result is consistent across all of the models. Finally we will examine 50-150 hPa November mean partial ozone columns from Syowa (69.0°S, 39.58°E) to see if indeed a statistically significant change in trends is observable.
DE: 0340 Middle atmosphere: composition and chemistry
DE: 3334 Middle atmosphere dynamics (0341, 0342)
DE: 3337 Global climate models (1626, 4928)
DE: 3349 Polar meteorology
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005