1. The dynamical signal in stratospheric temperatures from satellites
Changes and interannual variability ( )
Paul J Young1,2, S Solomon1, D W J Thompson3, K H Rosenlof1,
J-F Lamarque1,2,4, S C Sherwood5, Q Fu6
Note, additional co-authors
Based on novel method that Susan, Qiang and Pu Lin started with MSU data
(1) NOAA-ESRL, (2) CIRES-CU, (3) CSU Fort Collins, (4) NCAR, (5) U. NSW, Aus. (6) U. Washington
Thanks to Craig Long and Roger Lin (NOAA - data); Bill Randel & Fei Wu (NCAR - data); Eric Ray, Bob Portmann, Sean Davis (NOAA - discussions)

2. Outline Dynamical (Brewer-Dobson) temperature signal
The MSU/SSU temperature data
Horizontal patterns and interannual variability from Brewer-Dobson circulation
Long-term changes and the B-D circulation
Summary
Two results sections:
Interannual variability
L-T changes

3. How do we get a dynamical temperature signal?
COOLS
HEATS
Opposite-sense anomalies from stronger/weaker than average
Expansion -> cooling
Compression -> warming
Holton et al. 1995

4. Annual temperature cycle - Asymmetric wave driving
= maximum wave driving (NH winter)
(> 30°S/N)
Ann cycle in extratropics (50%)…
…balanced in tropics (50%)
(30°S – 30°N)
MSU T4 analysis from Yulaeva et al. 1994

5. Temperature data: MSU and SSU
Microwave/Stratospheric sounding units
Monthly/zonal mean anomalies,
Tropical
tropopause
Polar
tropopause
Randel et al. 2009

6. Horizontal patterns and interannual variability
(De-trended data)
Highlight de-trended data

7. Winter correlations: Spider on the mirror
High lats (>50N) and tropics
High lats (>50S) and tropics
NH, DJF
SH, JJA
SSU 27
SSU 26
SSU 25
Pairs of lines (tropics and high latitudes) for each satellite channel, for NH winter (DJF) and SH winter (JJA).
Data are normalized to mean = 0 and std dev = 1.
Dotted lines show timing of El Chichon and Mt Pinatubo.
Line pairs are significantly anti-correlated.
Anomalies persist in vertical
MSU T4
1979
2005
1979
2005
Individual signals of SH 2002 winter, ENSO, others….?
Young et al. in prep

8. Tropics-S/N Pole correlations by month
Local correlation with…
> 60° N
> 60° S
SSU 27
Out-of-phase in hemispheric winter (B-DC signal)
SSU 26
In-phase in NH summer (weak in SH summer)
Altitude
SSU 25
Local monthly time series correlation with NH/SH high latitudes
Shading where |r| > ~ 0.4 (t-test signif at 95% level)
Still looking at in-phase NH summer - “seasonal memory” / NOy perhaps…?
MSU T4
Young et al. in prep

9. Brewer-Dobson circulation signals 1979-2005
See also Fu et al. (in review) for MSU discussion

10. Tropical/extratropical linear trends, 1979-2005
SSU 27 ?
Changes in Tropics and extratropics balance
 adiabatic process ?
SSU 26
Altitude
= B-DC strengthening?
SSU 25
Black line = global mean; extratropics is avg poleward of 30°N/S
Where tropical and extratropical trends deviate from global mean
Note April-May plot
Distorted SH pattern due to ozone hole cooling
= B-DC weakening?
MSU T4
April  May
Young et al. in prep

11. B-DC seasonality change / weakening
SSU 27
SSU 26
B-DC seasonality change / weakening
B-DC strengthening
Altitude
SSU 25
Trend and trend-mean trend - highlight latitudinal structure
Persistence in vertical
Long-term strengthening tendency robust to (e.g.) 2002 and volcanoes
MSU T4
Ozone-related cooling
Young et al. in prep

12. Consistency with radiosonde trend
Satellites on the left; radiosondes on the right
MSU T4 pattern not reproduced in IPCC AR4 models (see Fu et al.)
Young et al. in prep

13. Summary Wintertime B-D signal clear through the vertical
“Seasonal memory” in NH summer? (model?)
Satellites/radiosondes & adiabatic arguments  change in strength/seasonality of B-DC over last ~30 years
Evidence for long term tendency? Still looking at decadal patterns, but appears winter strengthening is robust

14. Extras – “seasonal memory”

15. Summer correlations: “seasonal memory”?
Temperature data
Ozone data
Subtract F10.7cm regression

16. Summer correlations: “seasonal memory”?
Temperature data
Ozone data
High lat-tropical T correlation from ozone?
O3 anomalies persist through, e.g., NOy transport (Tegtmeier et al. 2008)
Subtract F10.7cm regression