HR: 0830h
AN: A51A-02    [Abstracts]
TI: Solar Cycle Response and Trends in Upper Stratospheric and Lower Mesospheric Ozone From HALOE
AU: * Remsberg, E E
EM: Ellis.E.Remsberg@nasa.gov
AF: NASA Langley Res. Ctr., Atmospheric Sciences Research, MS 401B, Hampton, VA 23681 United States
AB: Time series of HALOE ozone for the period 1991-2004 were analyzed for their seasonal, interannual, solar cycle (SC), and trend terms. To do this, the HALOE Level 2 ozone profiles were integrated vertically into half-Umkehr pressure layers (about 2.5 km thick) and then averaged zonally for each period when the HALOE sunrise (SR) or sunset (SS) tangent-point measurements cycled through a given 10-degree latitude bin. By conducting analyses within pressure layers, one can separate out the effects of local chemistry and net transport on the ozone from the effects of a cooling or heating of the underlying atmospheric column that contributes to the periodic variations in a time series of ozone on an altitude surface. Analyses were conducted for 9 latitude zones Equatorward of 45S and 45N and 10 pressure layers from about 9.6 mb to 0.35 mb, the upper stratosphere and lower mesosphere. Model terms for each time series were added as they were found to be significant. The 11-yr SC response in ozone is prevalent and generally in-phase throughout this domain. Maximum response occurs in the subtropics at about 1.7 mb in the northern hemisphere (25N), but at about 3.5 mb in the southern hemisphere (15S). Peak amplitude for the SC response is near 1.5% for the NH, but about half that for the SH. Minimum (and nearly non-significant) response amplitudes of about 0.2% were found near the tropical stratopause; they were also out-of-phase with the SC total flux. Tropical SC responses increase to about 0.65% at 0.5 mb and at 4 mb, and they also come back in-phase. It is strongly suggested that this overall pattern of the decadal-scale ozone response across the zonal-mean cross section is not entirely due to photochemistry, but that some kind of dynamical forcing is also affecting the ozone and by a different amount for the two hemispheres. After accounting for the seasonal, interannual, and SC terms, there is no clearly significant loss or recovery for ozone in the upper stratosphere for this recent 13-year period, at least for the low and middle latitudes.
DE: 0340 Middle atmosphere--composition and chemistry
DE: 0341 Middle atmosphere--constituent transport and chemistry (3334)
DE: 1600 GLOBAL CHANGE (New category)
SC: Atmospheric Sciences [A]
MN: 2005 Joint Assembly