1. The Modulation of Tropopause- level Wave Breaking by the Madden Julian Oscillation Richard Moore 1, Olivia Martius 2, Thomas Spengler 2 & Huw Davies 2

2. Motivation Average MJO Phase Shading: anomaly from DJF average 250 hPa Wind Velocity500 hPa Height Quantitatively assess the behavior of wave breaking that accompanies the observed flow anomalies

3. Roadmap Ingredients of analysis Briefly outline the climatological response of WB to MJO forcing Combine climatological and case study viewpoints to gain further insight Simplify and summarize via a ‘Cartoon’ interpretation of observed evolution

4. Data & Methodology ERA-40 Re-Analysis Data for NH Winter from 1979-2002: Wave breaking (Wernli & Sprenger 2007; Martius et al. 2007) Surface cyclone frequency (Wernli et al. 2006) Atmospheric blocking frequency (Croci-Maspoli et al. 2007) 10 MJO Indices (Climate Prediction Center)  Combine a climatological and case-study analysis of the response to MJO forcing

5. “The basic criterion for saying whether a wave of any kind is breaking is whether material contours and surfaces are being irreversibly deformed rather than simply undulating back and forth as is assumed in linear wave theory” McIntyre and Palmer 83 Extratropical Wave Breaking

6. PV on 325K January 2007 troposphere, low PV stratosphere, high PV Synoptic Scale Rossby Wave Breaking

7. ‘Lifecycle’ Separation of Wave Breaking (WB) Events cyclonic life-cycle in cyclonic shear anticyclonic life-cycle in anti- cyclonic shear Thorncroft et al. 93 jet Dynamical Tropopause LC1, AC LC2, C LC1/LC2 wave breaking in ERA-40: Martius et al. 2007

8. Wave Breaking Frequency: 1979- 2002 DJF Cyclonic (LC2) on 310 KAnticyclonic (LC1) on 330 K

9. PV on 320K SLP strong convective activity along eastern flank formation of low pressure systems L Floods in Algeria November 2001 cyclonic windfield which can reach the surface wind on 850hPa precipitation IR meteosat Links to Severe Weather

10. Massacand et al. 98, 01 Alps PV-streamer wind field sea tropopause Links to Severe Weather Gondo October 2000

11. A disruption in the midlatitude westerlies due to the presence of a quasi-stationary high pressure system TP Z Atmospheric Blocking - PV Anomaly

12. Cyclonic WB Anomalies Average for MJO Phase Shading: anomaly from DJF average MJO INDEX 3 (120E)MJO INDEX 7 (40W) Cyclonic WB on 310 K

13. WB Anomalies: Overview Statistically significant anomalies are prevalent Dynamical distinction between baroclinic lifecycles is instructive Strong anti-correlation, fairly rapid transition between anomalies of opposite sign Cyclonic WB on 310 K Anticyclonic WB on 340 K

14. Outstanding Questions What is the relationship between the tropical convection and the observed jet – wave breaking anomalies? Might wave breaking be integral to the observed evolution?

15. Direct Impact of MJO Convection Shading: Daily Mean OLR Streamfunction Anomaly POSNEG January 16, 1993 upper-level anticyclone: shifts jet to the north; local jet intensification

16. Jet / WB Structure Predisposition to anticyclonic lifecycle Weak waveguide in central Pacific coincides with anticyclonic WB WB locally shifts jet north + - + - + 250 hPa Velocity Anticyclonic WB 12Z January 16, 19932 PVU on 310 K 2 PVU on 330 K 2 PVU on 350 K Shading: instantaneous 250 hPa velocity

17. Jet / WB Structure Cyclonic WB in west- central Pacific on northside of locally- enhanced jet baroclinic instability? 250 hPa Velocity Cyclonic WB + - 12Z January 28, 1993

18. Jet / WB Structure: Index 7 (40W) Eastward extended, zonal jet – strong waveguide Southward shift over Asia – cyclonic lifecyle WB shifts jet southward + - 12Z February 5, 1993 - + -

19. 3 (120E)4 (140E)5 (160E)6 (120W) WB and PNA-like signal Average MJO Phase Shading: anomaly from DJF average 500 hPa HeightCyclonic WB on 310 K MJO Index:7 (40W)

20. Anticyclonic WB Anomalies Average for MJO Phase Shading: anomaly from DJF average MJO INDEX 3 (120E)MJO INDEX 7 (40W)

21. modulation of sub & extratropics Northward shifted jet over Asia Anticyclonic WB in central Pacific Double jet structure Enhanced blocking frequency in central Pacific

22. modulation of sub & extratropics Pattern shifts east Cyclonic WB ensues on northside of zonally, locally- strong jet Surface cyclone often co-located in time and space with cyclonic wave breaking event LC2 wave breaking leads to quick transition of PNA

23. modulation of sub & extratropics Single jet extended to the east, southward shift over Asia Cyclonic WB (surface cyclones) eastern Pacific in jet exit region Subsequent to this time, in absence of MJO convection the jet breaks down and retreats westward

24. Questions? http://www.met.reading.ac.uk/~pete/

25. MJO Indices http://www.cpc.noaa.gov/products/precip/CWlink/daily_mjo_index/mjo_index.html based on 200 hPa velocity potential

26. Anticyclonic WB Anomalies Average for MJO Phase Shading: anomaly from DJF average MJO INDEX 3 (120E)MJO INDEX 7 (40W)

27. LC1, AC instantaneous field Shading: anomaly from DJF average

28. LC2, C instantaneous field Shading: anomaly from DJF average

29. Jet Structure MJO forcing changes jet strength, meridional & longitudinal location + anomaly - anomaly 250 hPa Jet:

30. Surface Cyclone Frequency MJO Index 3MJO Index 7 @ @ - anomaly + anomaly

31. What is the MJO? Dominant source of tropical intraseasonal variability Large-scale coupled patterns in deep convection & atmospheric circulation Characteristics: –Zonal scale ~ 12-20K km –Eastward propagation ~ 5 m/s –Lifecycle ~ 48 days http://www.met.reading.ac.uk/~pete/

32. Wave Breaking Frequency: 1979- 2002 DJF Cyclonic (LC2) on 310 KAnticyclonic (LC1) on 330 K