1. Page 1 AD hoc Workshop, TC working Group, 12. June 2007, Taipei Progress Report from the GKSS group Hans von Storch and Frauke Feser Institute for Coastal Research GKSS Research Center Geesthacht, Germany

2. Page 2 AD hoc Workshop, TC working Group, 12. June 2007, Taipei three seasonal runs, MAM, JJA and SON 1994, 1998 and 2004, - spectrally nudged to wind components given by NCEP 2 at 850 hPa and above for scales larger than about 700 km (about 20 days damping time at 850Hpa; 2 hours at 100 hPa) - emerging analysis with own tracking program to test sensitivities and detection strategies based on band-pass filtered SLP - using Kevin Hodge’s (conventional) program for systematic analysis Status per June 2007

3. Page 3 AD hoc Workshop, TC working Group, 12. June 2007, Taipei Spatial scale separation Feser, F., and H. von Storch, 2005: Spatial two-dimensional discrete filters for limited area model evaluation purposes. Mon. Wea Rev 133, 1774-1786 Design of digital filters for discriminating different spatial scales. Expected added value in medium scales, if large scale sufficiently well described.

4. Page 4 AD hoc Workshop, TC working Group, 12. June 2007, Taipei Band-pass filtering SLP fields Spatially filtered air pressure fields on 17 August 1997. Top: large scales retained (diameter > 600 km) Bottom: medium scales retained (diameter 180-360 km)

5. Page 5 AD hoc Workshop, TC working Group, 12. June 2007, Taipei Colour: meso-scale downscaling simulation by CLM; contours. NCEP SLP Courtesy. Michael Böttinger (DKRZ) and Frauke Feser (GKSS)

6. Page 6 AD hoc Workshop, TC working Group, 12. June 2007, Taipei Detection criterion all points along track: band pass filtered mslp  -0.5 hPa at least one point in marine area at last one point: - band pass filtered mslp  -0.5 hPa, and - v max  20 m/s in a circle with radius of 3 grid points, - mslp  990 hPa distance between last and first point at least 6 grid points

7. Page 7 AD hoc Workshop, TC working Group, 12. June 2007, Taipei Case: JJA 1994. Tracks in band- pass filtered pmsl  -1 hPA Deepest low in band-pass filtered pmsl  -5 hPa

8. Page 8 AD hoc Workshop, TC working Group, 12. June 2007, Taipei track identified - nr. 6 length 29; begin: 101, 64.00 end: 77,85 time: 1466 - 1762 min press -19.3293 963.613 hPa; max wind 58.6469 m/sec

9. Page 9 AD hoc Workshop, TC working Group, 12. June 2007, Taipei track identified - nr. 6 length 29; begin: 101, 64.00 end: 77,85 time: 1466 - 1762 min press -19.3293 963.613 hPa; max wind 58.6469 m/sec

10. Page 10 AD hoc Workshop, TC working Group, 12. June 2007, Taipei track identified - nr. 6 length 29; begin: 101, 64.00 end: 77,85 time: 1466 - 1762 min press -19.3293 963.613 hPa; max wind 58.6469 m/sec

11. Page 11 AD hoc Workshop, TC working Group, 12. June 2007, Taipei track identified - nr. 3 length 173 ** begin : 106,54 end : 68, 90. ** time : 822 - 994 min press -8.7 981.4hPa; max wind 49.5526 m/sec

12. Page 12 AD hoc Workshop, TC working Group, 12. June 2007, Taipei track identified - nr. 3 length 173 ** begin : 106,54 end : 68, 90. ** time : 822 - 994 min press -8.7 981.4hPa; max wind 49.5526 m/sec

13. Page 13 AD hoc Workshop, TC working Group, 12. June 2007, Taipei track identified - nr. 3 length 173 ** begin : 106,54 end : 68, 90. ** time : 822 - 994 min press -8.7 981.4hPa; max wind 49.5526 m/sec

14. Page 14 AD hoc Workshop, TC working Group, 12. June 2007, Taipei

15. Page 15 AD hoc Workshop, TC working Group, 12. June 2007, Taipei

16. Page 16 AD hoc Workshop, TC working Group, 12. June 2007, Taipei

17. Page 17 AD hoc Workshop, TC working Group, 12. June 2007, Taipei head Best guess NCEP reanalysis CLM

18. Page 18 AD hoc Workshop, TC working Group, 12. June 2007, Taipei head Case: JJA 1998. Tracks in band- pass filtered pmsl  1 hPA Deepest low in band-pass filtered pmsl  5 hPa

19. Page 19 AD hoc Workshop, TC working Group, 12. June 2007, Taipei head Case: JJA 1998. Tracks in band- pass filtered pmsl  1 hPA Deepest low in band-pass filtered pmsl  4 hPa

20. Page 20 AD hoc Workshop, TC working Group, 12. June 2007, Taipei Seasonal typhoon counts Typhoon Seasons SE-Asia/NW-Pacific CLM/OBSMAMJJASON 19943/216/1813/14 19983/03/45/10 Using Kevin Hodge’s tracking algorithm and subjective, preliminary choice of critical parameters for RCM, and “best tracks” for obs.

21. Page 21 AD hoc Workshop, TC working Group, 12. June 2007, Taipei Conclusions (Some) typhoons can be described by regional atmospheric models run in the climate mode. Digital 2-d filter helpful for detection. Our simulations, or detection, fails with typhoons in the SW part of the considered region. Results represented are preliminary. We need better data for validation.