1. A SEARCH FOR FREE ROSSBY WAVES AND FOR VAN LOON’S TEMPERATURE VARIATIONS IN THE SOUTHERN HEMISPHERE STRATOSPHERE Roland Madden, NCAR, USA

2. Published Northern Hemisphere Results A) out-of-phase temperature variations B) importance of eddy heat transports, v*T* C) free and forced Rossby wave hypothesis to explain the time variations in v*T*

3. Published Northern Hemisphere Results A) out-of-phase temperature variations B) importance of eddy heat transports, v*T* C) free and forced Rossby wave hypothesis Southern Hemisphere Search for: A) out-of-phase temperature variations in Microwave Sounding Unit (MSU) data B) role of eddy heat transports, v*T*, in ERA40 data C) evidence to support the free and forced Rossby wave hypothesis

4. van Loon et al., 1975: MWR 30hPa Zonal Mean Temperatures

5. free an forced Rossby wave hypothesis v*T* = v fr T fr + v fo T fo + v fr T fo + v fo T fr superscript ‘fo’ means forced wave which is approximated by the time average superscript ‘fr’ means free wave whose amplitude and propagation is estimated from the data

6. Madden and Labitzke, 1981:JGR o o o o o o o o Observed Wave-1 v*T* Hypothesized free and forced Rossby wave January 1979 Wave-1 Horizontal Eddy Heat Transport Across 60N at Indicated Pressure Levels 100hPa 10hPa v fo T fo + v fr T fo + v fo T fr

7. Search for out-of-phase temperature variations across 60S in Microwave Sounding Unit data, 1992 - 2004

8. Microwave Sounding Unit

9. Channel 4 MSU Data 1Jul – 31 Oct 1996

10. Channel 4 MSU Data 1992 – 2004 Zonally Averaged T 50S vs 70S Coh 2 Phase

11. Role of horizontal heat transports in ERA40 data, April 1996 – March 1997

12. Zonally Averaged v*T* at 60S and 100hPa Total - red; Wave-1 only - dotted; Wave-2 only - solid ERA40 Data

14. v*T* Across 60S at 100hPa vs Zonally Averaged T at 50S Minus that at 70S

15. v*T* Across 60S at 100hPa vs Zonally Averaged T at 50S Minus that at 70S

16. Role of large-scale waves in ERA40 data

18. free an forced Rossby wave hypothesis v*T* = v fr T fr + v fo T fo + v fr T fo + v fo T fr v fr T fr =0 free Rossby waves transport no heat v fo T fo don’t contribute to time variations Time Varying v*T* ~ v fr T fo + v fo T fr

19. Wave-1 v*T* red v fr T fo + v fo T fr black forced wave approximated by time average free wave by time deviations

20. SUMMARY Out-of-phase temperature variations between mid- and high latitudes are also present in the Southern Hemisphere stratosphere

21. SUMMARY Out-of-phase temperature variations between mid- and high latitudes are also present in the Southern Hemisphere stratosphere Time variations of horizontal eddy heat transports across 60S are an important driving force

22. SUMMARY Out-of-phase temperature variations between mid- and high latitudes are also present in the Southern Hemisphere stratosphere Time variations of horizontal eddy heat transports across 60S are an important driving force Although one case in 1996 was consistent with the wave interference hypothesis, more evidence is needed to show that the time variations were, indeed, due to a free Rossby wave

23. obrigado

24. April 1996 – March 1997 Comparing MSU and ERA40 Zonally Averaged Temperatures