Adviser: Huang-Hsiung Hsu Speaker:Ming-Ying Lee

1. Decadal Teleconnection in the Northern Hemisphere Adviser:Huang-Hsiung Hsu Speaker:Ming-Ying Lee 01Jul2008

2. How many Decadal to Mutidecadal fluctuations in the Northern Hemisphere ?

3. Pacific Decadal Oscillation (PDO) Typical wintertime Sea Surface Temperature (colors), Sea Level Pressure (contours) and surface windstress (arrows) anomaly patterns during warm and cool phases of PDO Warm phase Cool phase From: http://jisao.washington.edu/pdo/

4. Atlantic Multidecadal Oscillation (AMO) Upper panel: AMO index: the ten-year running mean of detrended Atlantic sea surface temperature anomaly (SSTA, °C) north of the equator. Lower panel: Correlation of the AMO index with gridded SSTA over the world ocean (all seasons). The thick contour is zero and thin contours denote the 95% significance level. Form:http://www.aoml.noaa.gov/phod/amo_fig.php

5. Arctic Oscillation (AO) From:http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.shtml

6. North Atlantic Oscillation(NAO) Positive NAO Negative NAO From : http://www.ldeo.columbia.edu/res/pi/NAO/

7. AOcor=-0.75 ENSOcor=0.51 A new Decadal to Mutidecadal fluctuation in the NH?? ??

9. COR=0.97 EOF analysis Northern Hemisphere

10. Cor=0.87 PC2 and Climate Index All index had performed 9-yrs running except the AMO uesd 25-yrs running

11. What are the impacts of the AMO? Red and blue colored dots represent positive and negative correlations of Northern Hemisphere summer rainfall with the AMO index. When the AMO is positive (warm Atlantic) there is less rainfall over most of the United States and northeastern South America, and more rainfall in southern Alaska, northern Europe, west Africa and Florida. Form:http://www.aoml.noaa.gov/phod/amo_fig.php

12. AMO & hurricanes During warm phases of the AMO, the numbers of tropical storms that mature into severe hurricanes is much greater than during cool phases, at least twice as many. Since the AMO switched to its warm phase around 1995, severe hurricanes have become much more frequent and this has led to a crisis in the insurance industry. Form:http://www.aoml.noaa.gov/phod/amo_fig.php

13. Analysis

14. Normalize of PC2 N(1970~85) P2(1990~2001) P1(1958~66) (16yrs) (9yrs) (12yrs) → Composite:P1&P2 minus N

15. Composite Verticla profile(40 ° ~60°N) Geopotential Temperature Annual mean of H200 and H500 Significant at the 5% level are shaded

16. Composite Seasonal H200(DJF) H200(MAM) H200(JJA) H200(SON) Significant at the 5% level are shaded

17. Note:BADC(Britich Atmospheric Data Centre)

18. PC2 AMO SH NH Detrend,running 25yrs running °C Data from: NCDC (ftp://ftp.ncdc.noaa.gov)

19. Summary A decadal to mutidecadal pattern in NH is identified. Major characteristics: • Coherent geopentential height (and temperature) perturbation in the upper troposphere, which almost encircles the middle to high latitude of the NH. • The pattern is most apparent over the high-latitude Eurasia continent and the north Pacific in annual mean. Similar signal also appears during the boreal autumn and winter season, but with weaker amplitude. • Decreasing trend in the late 1960s and increasing trend after the late 1980s. • Temporal fluctuation almost coincides with the fluctuation of the AMO and NH mean surface temperature.

20. Thanks!! 

21. EOF1 ≡Global Warming EOF2 ≡ PDO 10.2% 8.0% EOF3 ≡ AMO 55.7% Parker et al.(2007)

22. ERA40 Geopotential 200hPa 500hPa 850hPa

23. Composite Annual mean Kaplan SST ERA40 T2m Significant at the 5% level are shaded

24. Projection of annual H200 onto EOF2 Line:annual mean Bar:9 yrs running

25. Composite 200hPa Zonal wind MAM DJF Annual JJA SON

26. Correlation H200 .vs. PC1 H200 .vs. PC2

27. Is it a Global fluctuation?

28. Southern Hemisphere EOF analysis Tropics

29. 47.9% 300N~700N 30.4% 90.2% 700S~300S EOF analysis EOF 1 89.6% 300S~300N