Dynamical control of ozone transport and chemistry from satellite observations and coupled chemistry climate models Mark Weber 1, Sandip Dhomse 1, Ingo Wohltmann 2, Veronika Eyring 3, Markus Rex 2 and Martin Dameris 3 (1)Institute of Environmental Physics, University Bremen, Bremen (2)Alfred-Wegner Institute for Polar and Marine Research, Potsdam (3)Institute of Atmospheric Physics, DLR Oberpfaffenhofen SPARC General Assembly 2004 Victoria, BC, Canada, 1-6 August 2004

Overview Diagnostics: Planetary wave driving and total ozone (OClO) Data sources: GOME (O3 and OClO), TOMS, TOMS-SBUV merged dataset Met Analyses: ERA40, NCEP, UKMO Topics:  Planetary wave driving and ozone/temperature (introduction)  Tropospheric forcing and winter ozone gain  Dynamical control of summer ozone  Chlorine activation/chemical ozone loss (polar vortex)

Annual cycle in total ozone

Interannual variability Winter/spring ozone Photochem. summer decay

GOME r= Ozone tendency in tropics and high latitudes after Fusco & Salby, 1999, Randel et al. 2002

K Temperature and zonal winds Cold tropical lowermost stratosphere/tropopause cold polar vortex Strong polar jet Link between T variability in tropics to planetary wave driving (Yulaeva et al. 1994) Link between planetary wave driving and Arctic T variability (Newmann et al. 2001)

EP (Heat) Flux and Residual Circulation

ozone production cold/warm winters heterogenous/gasphase chemistry Meridional circulation ~2-4 y EP (heat) flux Planetary scale wave activity Extratropical Pump Brewer-Dobson circulation Residual circulation Ozone & T variability chemistry/transport EP (Heat) Flux and Residual Circulation

Annual cycle of GOME and E39/C TOZ NH SH

Tropospheric forcing and spring/fall ozone ratio  GOME ozone ratio  50°-90°  Sep over Mar (SH) Mar over Sep (NH)  Winter heat flux  40°-70°  100 mbar  Sep-Mar (Mar-Sep) integrated and averaged SH anomaly 2002 cold Arctic winter/spring seasons Update from Weber et al warm Arctic winter/spring seasons Antarctic winter/spring

„Downward control“ in ozone observations SBUV V8 GOME NNORSY

Ozone winter gain and summer transition  ERA40 vs UKMO  Interannual variability of winter heat flux correlates well with winter ozone gain  Winter heat flux higher in ERA40 (too much transport)  E39/C vs GOME  lower interannual variability in winter (NH)  weaker wave driving in SH (cold bias?)  Photochemical decay about 3m (>50°N) and 2.5 m (>62°N)  Good agreement between GOME and E39/C

Early 80s vs. late nineties  Correlation with ERA40 in early 80s and SH very poor ERA40

EP-Flux and polar ozone  TOMS/SBUV O3:  March 65°-70°N  NCEP EP-Flux:  15 Nov -28 Mar  100hPa  45°-75°N r=0.74  Lower correlation (0.69) in 80s  less O3 change for a given EP flux anomaly  Higher correlation (0.84) in 90s  more ozone transport for a given EP flux anomaly r=0.74

Long term trend in high latitude total ozone

Long term trend in high latitude total ozone winter gain  Linear or EESC trend model fits equally well (r=0.90 vs r=0.91)  Minimum in mid nineties has strong dynamical component (change in atmospheric dynamics related to Pinatubo? Opossite phasing during El Chichon) SBUV8

Long term trend in winter planetary wave activity? NH Sep-Mar SH Mar-Sep 40°-70°

Long term trend in winter planetary wave activity? 22

Tropospheric forcing and chlorine activation  OClO  BrO+ClO –> OClO + O  Measured in twilight inside the polar vortex  Maximum vertical column at 90° solar zenith angle integrated over the winter  Below 92°SZA OClO is a measure of chlorine activation ECMWF Update from Weber et al High chlorine activation persisted during SH anomaly 2002 LAD LSQ

Summary & Conclusion  Compact relationship between winter ozone gain and seasonal heat flux for both hemispheres (late nineties/early 2000)  Connection between chlorine activation/chemical loss to planetary wave driving can be explored  Summer ozone levels are tied to wave activity of the previous winter (see Fioletov and Shepherd 2003)  Met. Analyses  good measure of interannual variability  differences in strength of high latitude ozone transport varies (ERA40 higher than NCEP/UKMO)  Correlations between wave driving & ozone particularly well in 90s  E39/C (and possibly other CCMs)  less interannual variability in winter  Summer bias of 20% to observations at mid- to high latitude  No summer minimum in SH  Data still to be explored: GOME NO 2 and ENVISAT

Tropospheric forcing, ozone transport, and chlorine activation  GOME ozone ratio  50°-90°  Sep over Mar ratio (SH) Mar over Sep ratio(NH)  GOME OClO  Maximum vertical column 90°SZA  Integrated over winter and divided by 365 days Update from Weber et al LAD LSQ  Winter heat flux (planetary wave activity)  40°-70° mean at 100 hPa  integrated from Sep to Mar and averaged Potential longterm changes in planetary wave forcing (residual circulation) modifies ozone transport and chemistry

Record high absolute lower stratospheric heat flux on 20th/21st September (ERA ) Splitting of the polar vortex on 26th September 2002 First major stratospheric warming in SH

ERA15/ERA40

PSC Volume in SH

+5 m+6 m +8 m +7 m

spring/fall ratio for different months +10 m +11 m +9 m + 1 y