1. Structure and Formation Process of an Orographic Line-shaped Rainfall System during Baiu Season in Western Kyushu, Japan Ayako Nakamura, Hiroshi Uyeda, (HyARC, Nagoya University, Nagoya, Japan) Osamu Morita, (Graduate School of Sciences, Kyushu University, Fukuoka, Japan) Yasufumi Kitazaki, Hideki Beppu (Fukuoka District Meteorological Observatory, JMA, Fukuoka, Japan)

2. Three rainbands in Kyushu Goto Islands Isahaya line 1997/07/11/16:00JST 2002/07/01/12:20JST Koshikijima line 2001/06/19/11:30JST Goto line Nagasaki Peninsula Koshikijima Islands Max crest : 461m Max crest : 569m Max crest : 511m Japan Kyushu Sapporo Z=2.0km

3. Objective 2001/06/19/11:30JST Goto line How do these lines form from islands with low mountains in moist lower atmosphere? →many analyses ・ Goto line →few analyses Study on formation mechanism ・ Isahaya line and Koshikijima line PURPOSE To clarify 1. the structure of the 19 June 2001 Goto line 2. the formation process of the 19 June 2001 Goto line →many analyses ・ Goto line →few analyses Study on formation mechanism ・ Isahaya line and Koshikijima line

4. observation sites Japan Kyushu Hirado Fukuo ka Sefuriya ma Goto Islands the Sefuriyama radar data (the JMA operational radar) upper-air soundings data (at Fukuoka) JMA wind profiler data (at Hirado) Meso Regional Analysis data Sapporo

5. Environme ntal field Relative Humidity at surface convectively unstable 780m LCL RH > 80% at surface ( by MANAL data)

6. behavior and horizontal structure Sefuri Mts. 11:40 12:50 09:40 16:00 north of Sefuri Mts. over Sefuri Mts. over Sefuri Mts. dissipatio n cellular structure north of Sefuri Mts. 11:40 12:50 09:40 16:00 north of Sefuri Mts. over Sefuri Mts. over Sefuri Mts. dissipatio n 130 ～ 200km Sefuri Mts. Z=2.0km 16:00 over Sefuri Mts. Z=2.0km Sefuri Mts. 11:40 north of Sefuri Mts. over Sefuri Mts. 12:50 dissipatio n over Sefuri Mts.

7. 16:00 Vertical structure 09:40 ～ 11:40 11:40 ～ 12:50 Sefuri Mts. Distance from Sefuriyama radar site [km] north of Sefuri Mts. over Sefuri Mts. 11:40 12:50 09:40

8. Wind profile and Froude number 25 ～ 29m/s Froude number Fr = 4.8 （ > 1 ） Upslope forcing by Goto Islands By Smolarkiewicz and Rotunno(1989) h: top height of a mountain U 0 : a uniform horizontal wind N: Brunt-Vaisala frequency generation of convective clouds U 0 =15m/s ， N=6.8×10 -3 /s ， h=460m Wind Profiler MANAL 09JST 19 JUNE 2001

9. convective cells Distance from Sefuriyama radar site [km] about 28m/s northeastward

10. Summary over no high-mountainsover mountains ( >1km height) upslope forcing

12. Weather map at surface

13. cloud image of GMS-5

14. Comparison of other lines Isahaya line 1997/07/11/16:00JST 2002/07/01/12:20JST Koshikijima line 2001/06/19/11:30JST Goto line (By Takeda et al. 1999) (By Nakamura et al. 2002)

15. Horizontal Feature 16:00 north of Sefuri Mts. over Sefuri Mts. 11:40 12:50 09:40

16. Vertical Feature 11:30

17. Time variation Z=2km Z=6km Z=10km

18. Isahaya line Takeda et al. 1999

19. Koshikijima line Nakamura et al. 2002

20. Froude number By Smolarkiewicz and Rotunno(1989) h: top height of a mountain U 0 : a uniform horizontal wind N: Brunt-Vaisala frequency horizontal detouring the obstacle the vertically propagating-wave pattern Small Fr （ <1 ） Large Fr （ >1 ）