Department of Atmospheric Science, Chinese Culture University, Taipei, Taiwan

1. The abrupt increase of winter rainfalls in early 1980s in Northern Taiwan and the weakening of the East Asian winter monsoon Department of Atmospheric Science, Chinese Culture University, Taipei, Taiwan Advisor: Chih-wen Hung Student: Pei-ken Kao

2. ?

3. (shaded) (contour) mm

4. surface wind Gray line: DJF, V<0, interannual variation of wind speed Thickness line: 11 years running mean Black line: DJF, interannual variation of wind speed

5. winter rainfall interannual variation

6. Taipei DJF rain days >=30mm/day rain days Total rain days Black bars: decadal variation Gray bars: interannual variation

7. plain stations hill and coastal stations winter rainfall interannual variation

8. Red box: plain stations green box: hill or coast stations

9. 1997-2005 DJF northeasterly monsoonal wind rainfall pattern frontal rainfall pattern

10. E: El Nino L: La Nina plain stations early period latter period hill and coastal stations

11. latter minus early period mm

12. latter minus early period °C

13. latter minus early period kg/g

14. conceptual model

15. END

16. Data • 8 CWB conventional surface stations and 377 ARMTS daily data(洪，2007; Hung, 2008; Chen et al., 1999). • JMA surface weather map, 1997-2005. • ERA40 re-analysis data (Uppala et al., 2005), 2.5°×2.5°, 1958-2003, monthly data. • HadISST, 1.0°×1.0°, 1870-2007, monthly data(Rayner et al., 2003). • CRU rainfall data, 0.5°×0.5°, 1901-2002, monthly data(Mitchell and Jones, 2005).

23. Only front

24. V > 0 + front

25. V > 0 + no front

27. 彭佳嶼風場