1. 1 Can variations in the tropical convection and circulation play a role in the variability of the Antarctic ozone? Leila M. V. Carvalho 1,2 and Charles Jones 1 1 ICESS, University of California, Santa Barbara 2 Dept. Atmospheric Science, Universidade de São Paulo

2. 2 Interannual variability of the Antarctic springtime TOMS Ozone (60.5S - 89.5S)

3. 3 QUESTION: Is the change in rate of depletion of the total Antarctic ozone after 1990 a result of the human control of CFC emission or does natural variability of circulation play a role in modulating the total ozone during the Spring (SEPT-OCT)? Is the change in rate of depletion of the total Antarctic ozone after 1990 a result of the human control of CFC emission or does natural variability of circulation play a role in modulating the total ozone during the Spring (SEPT-OCT)?

4. 4 Rational Variations in the zonal structure of the Polar Jet are important for the total Antarctic Ozone Variations in the zonal structure of the Polar Jet are important for the total Antarctic Ozone The Antarctic Oscillation (AAO), the Polar Vortex and the total Ozone over the Antarctic are related The Antarctic Oscillation (AAO), the Polar Vortex and the total Ozone over the Antarctic are related Carvalho et al. (2004) showed a link between the AAO phases and convection in the tropics (ENSO and Madden-Julian Oscillation) during DJF Carvalho et al. (2004) showed a link between the AAO phases and convection in the tropics (ENSO and Madden-Julian Oscillation) during DJF Thompson and Solomon (2002) have suggested a trend toward the high index polarity (positive phase) of the AAO linked to the negative trend of the total SH ozone (or increase in the ozone hole) Thompson and Solomon (2002) have suggested a trend toward the high index polarity (positive phase) of the AAO linked to the negative trend of the total SH ozone (or increase in the ozone hole)

5. 5 WHAT IS THE ANTARCTIC OSCILLATION? The Antarctic Oscillation (AAO) is known as the leading mode of variability of extratropical circulation in the Southern Hemisphere This mode of variability is characterized by deep and zonally symmetric or “annular” structures (Thompson and Wallace 2000) with opposite geopotential height perturbations over the pole and approximately in a zonal ring with center around 45 o S. The annular and zonally symmetric structure involves exchanges of mass between mid and high latitudes.

6. 6 The Daily AAO Index: 1979-2000 The daily AAO index is the leading mode of the EOF analysis of daily anomalies of the 700hPa geopotential height from Reanalysis (20-90 S). POSITIVE PHASE 700hPa ColdWarm Negative Phase

7. 7 Example of Filtering time-series

8. 8 Composites of SST and 200 hPa zonal wind (U200 LF ): Low-Frequency ( Retained Periods: above 365 days) Negative AAO PhasePositive AAO Phase U200 LF SST LF

9. 9 The Ozone Hole : observations and theory Discovery Discovery mid -1980’s: Large losses springtime (Sept-Oct) of total ozone over Antartica between 1975 – 1984 (300-200 DU from the 1960’s) mid -1980’s: Large losses springtime (Sept-Oct) of total ozone over Antartica between 1975 – 1984 (300-200 DU from the 1960’s) Theories: Theories: 1 ) Dynamical Theory – atmosphere circulation over the Antartica changed such that air from the troposphere (with less ozone) was carried into the polar lower stratosphere – less accepted 1 ) Dynamical Theory – atmosphere circulation over the Antartica changed such that air from the troposphere (with less ozone) was carried into the polar lower stratosphere – less accepted 2) Heterogeneous Chemistry (more accepted): reactions occurring with the surface of tine cloud particles formed in extremely cold conditions (polar stratospheric clouds – PSC). Compounds formed by the reaction on these PSCs allow nonreactive compounds containing chlorine to become reactive compounds => These reactive chlorine compounds catalytically destroyed ozone at an extremely rapid rate. The chlorine compounds are mostly from CFCs (human production) 2) Heterogeneous Chemistry (more accepted): reactions occurring with the surface of tine cloud particles formed in extremely cold conditions (polar stratospheric clouds – PSC). Compounds formed by the reaction on these PSCs allow nonreactive compounds containing chlorine to become reactive compounds => These reactive chlorine compounds catalytically destroyed ozone at an extremely rapid rate. The chlorine compounds are mostly from CFCs (human production) 3) Any other unknown additional forcing?? 3) Any other unknown additional forcing??

10. 10 The cold stratosphere and the polar vortex Sunshine (UV) heats the stratosphere Sunshine (UV) heats the stratosphere Polar Night => cools off by emitting IR radiation to space Polar Night => cools off by emitting IR radiation to space Weather systems in the stratosphere warm the polar regions. During the winter they are very weak Weather systems in the stratosphere warm the polar regions. During the winter they are very weak The Polar Jet (or vortex) results from the very cold polar region, weak weather systems and infrared cooling The Polar Jet (or vortex) results from the very cold polar region, weak weather systems and infrared cooling Reactions required for ozone loss also involve sunlight Reactions required for ozone loss also involve sunlight The basic ingredients for ozone loss are: cold temperatures with PSCs and sunlight => conditions observed in September and October – when the minimum of the ozone is observed. The basic ingredients for ozone loss are: cold temperatures with PSCs and sunlight => conditions observed in September and October – when the minimum of the ozone is observed.

11. 11 Seasonal evolution of the Polar Jet : u50hPa (m/s) AugustSeptember OctoberNovember

12. 12 Coupling Tropics with Extratropics, AAO, the Polar Jet and the Lower stratosphere Temperature during the Spring (September-October) Data: Data: 1. 25 years of reanalysis (1979-2003): zonal wind U 50hPa; 700hPa geopotential Height; temperature 50hPa; Outgoing Longwave Radiation (OLR) 2. Spatial Domain: 90S to 20 S (2.5x2.5 resolution. Time resolution: pentads 3. Only low Frequency (periods retained > 380 days) 4. Ozone data: TOMS (23 years)- pentads

13. 13 Combined EOF (September and October): H700, U50, T50, OLR – Low Frequency (EOF1: 29% of the total variance) OLR H700 T50 U50 EOF1 >0 : AAO negative phase EOF1 >0 : Convec. Tropic Subtrop. EOF1 >0 : Warm Stratosph. EOF1 >0 : Weak Polar Jet.

14. 14 Combined EOF Patterns: The combination of the annular pattern (H700) observed along with the lower stratosphere features (T50 and U50 and convective activity in the tropics and subtropics (OLR) The combination of the annular pattern (H700) observed along with the lower stratosphere features (T50 and U50 and convective activity in the tropics and subtropics (OLR) Tropics-Extratropics Interaction Pattern (TEIP). Tropics-Extratropics Interaction Pattern (TEIP). TEIP relates the Southern Hemisphere annular mode (Thompson and Wallace, 2000) to a tropical zonal wavenumber 3 structure TEIP relates the Southern Hemisphere annular mode (Thompson and Wallace, 2000) to a tropical zonal wavenumber 3 structure

15. 15 TEIP TIME-COEFFICIENTS Bimodal distribution IndexesAAO Niño 3.4 QBO PNA PNANAOPDO Correlation-0.740.290.0760.12-0.35 0.17 0.17 Correlation TEIP and other Atmospheric Indexes

16. 16 TEIP interannual variability

17. 17 OZONE COMPOSITES FROM TOMS Separating Pentads in October with EOF-1 > 75th Percentile and EOF-1 75th Percentile and EOF-1 < 25th Percentile Negative TEIPPositive TEIP Years: 1980,1982,1991,2000,2002, 2003 Years: 1983,1985,1993,1998,1999, 2001

18. 18 Ozone ratio: Positive/Negative TEIP

19. 19 TEIP and the Stratospheric Ozone Warming of the lower stratosphere and mid troposphere are consistent with the negative phase of the AAO and the weakening of the Polar Jet Warming of the lower stratosphere and mid troposphere are consistent with the negative phase of the AAO and the weakening of the Polar Jet The weakening of the Polar Jet can explain the enhancement of the Ozone in October The weakening of the Polar Jet can explain the enhancement of the Ozone in October How to explain the relationship with convective activity in the tropics that is not totally explained by ENSO? How to explain the relationship with convective activity in the tropics that is not totally explained by ENSO?

20. 20 Intraseasonal activity It has been reported in many studies the importance of the propagation of wave trains in intraseasonal time- scales (20-90 days) from tropics to mid-latitudes. It has been reported in many studies the importance of the propagation of wave trains in intraseasonal time- scales (20-90 days) from tropics to mid-latitudes. These wave trains affect circulation and convection in the tropics and subtropics These wave trains affect circulation and convection in the tropics and subtropics CAN INTERANNUAL VARIABILITY OF THESE INTRASEASONAL DISTURBANCES BE LINKED TO THE PATTERN OF CONVECTION OBSERVED IN THE COMBINED EOF? CAN INTERANNUAL VARIABILITY OF THESE INTRASEASONAL DISTURBANCES BE LINKED TO THE PATTERN OF CONVECTION OBSERVED IN THE COMBINED EOF? If so, ARE THESE VARIATIONS ALSO OBSERVED IN THE LOWER STRATOSPHERE SUCH THAT THE WEATHER IN THIS REGION DURING THE SPRING AFFECTS THE STRENGTH OF THE POLAR JET? If so, ARE THESE VARIATIONS ALSO OBSERVED IN THE LOWER STRATOSPHERE SUCH THAT THE WEATHER IN THIS REGION DURING THE SPRING AFFECTS THE STRENGTH OF THE POLAR JET?

21. 21 The investigation of the interannual variability of the global intraseasonal activity Data: 200hPa and 50hPa daily zonal wind Data: 200hPa and 50hPa daily zonal wind Method to obtain intraseasonal activity index (ISI): 1. Daily U was filtered (20-90 days) 2. Intraseasonal anomalies were squared (ISI) Method to obtain low frequency variations: 1. A low-pass filter was applied to ISI (ISI-LF)

22. 22 Sep-Oct Climatology of the ISI- U200hPa Sep-Oct Climatology of the ISI- U50hPa

23. 23 Zonal Mean of ISI-LF anomalies (200hPa) Sep-Oct Active ISI in the SH: Positive TEIP Composites are for the 75 th and 25 th EOF-1 Percentiles Pos TEIP Neg TEIP

24. 24 Zonal Mean of ISI-LF anomalies (50hPa) Sep-Oct Active ISI in the SH for TEIP+ Pos TEIP Neg TEIP

25. 25 ISI anomalies (low frequency) zonal averages: U50 (70S – 50S ) and U200 (40S – 2.5 S)

26. 26 Interannual variations of intraseasonal activity (20-70 days) over the Equator (eastern of the date line – western SA) Increase of Tropical Intraseasonal Activity after 1990

27. 27 Case study: Active ISI 50hPa – TEIP>0 10/03/200210/13/200210/23/200210/28/2002 Composites of U 50hPa anomalies (20-90 days) Composites of Total Ozone (TOMS)

28. 28 10/03/199310/13/199310/23/199310/28/1993 Case study: Quiescent ISI 50hPa – TEIP <0 Composites of U 50hPa anomalies (20-90 days) Composites of Total Ozone (TOMS)

29. 29 CONCLUSIONS The dynamical theory linking the troposphere activity to the stratosphere needs to be properly reconsidered. The dynamical theory linking the troposphere activity to the stratosphere needs to be properly reconsidered. In this regard, the coupling between tropics and extratropics dynamics is essential. In this regard, the coupling between tropics and extratropics dynamics is essential. During DJF, ENSO (in interannual time-scales) and MJO (in intraseasonal time-scales) seem to be two important forcings for the AAO polarity. During DJF, ENSO (in interannual time-scales) and MJO (in intraseasonal time-scales) seem to be two important forcings for the AAO polarity. During the SH spring, the activity of intraseasonal disturbances in the tropical/subtropical troposphere may also disturb the stratosphere. During the SH spring, the activity of intraseasonal disturbances in the tropical/subtropical troposphere may also disturb the stratosphere. Variations in the stratospheric circulation imply in changes in the pattern and strength of the polar jet. Variations in the stratospheric circulation imply in changes in the pattern and strength of the polar jet. The increase in these activities have a positive feedback for the total ozone and the ozone hole. The increase in these activities have a positive feedback for the total ozone and the ozone hole. Therefore: The Heterogeneous Chemistry Theory should be considered along with the Dynamical Theory to account for the variability, long-term trend and human impacts on the total ozone and the ozone hole, as well as to predict realistic scenarios for climate change. Therefore: The Heterogeneous Chemistry Theory should be considered along with the Dynamical Theory to account for the variability, long-term trend and human impacts on the total ozone and the ozone hole, as well as to predict realistic scenarios for climate change.