JMA

1. TYPHOON COMMITTEE Integrated Workshop on Urban Flood Risk Management in a Changing Climate: Sustainable and Adaptation Challenges Macao, China 06-10 September 2010 JMA Japan MeteorologicalAgency QPE/QPF of JMA Application of Radar Data Masashi KUNITSUGU Head, National Typhoon Center Japan Meteorological Agency

2. JMA Japan MeteorologicalAgency Purpose of QPE/QPF local meteorological office, local government , mass media, weather companies JMA Weather Information Observation data Products of QPE/QPF High resolution data (spatial, time, intensity)

3. Products of QPE/QPF of JMA *Composite of echo intensity (every 30 min) *Composite of echo top height (every 30 min) 　　　　　　　　　　* Radar/Raingauge-Analyzed Precipitation (every 30 min) 　　　　　　　*Very-Short-Range-Forecast(VSRF) of precipitation (every 30 min) （Application） 　　　 *Analyzed 10-min precipitation (every 5 min) *Precipitation Nowcasts (every 10 min) * Soil Water Index 　 　 　　　 　　　　　 * Runoff Index

4. JMA Japan MeteorologicalAgency Technical base of QPE/QPF Digitalized radar (automatic rejection of ground clutter) Raingaugenetwork Communication network with rapid transmission High performance computer NWP model with high resolution

5. Precipitation observation equipment Radar Raingauges

6. JMA Japan MeteorologicalAgency Radar/Raingauge-Analyzed Precipitation ○Calibrate ‘radar estimate’ with raingauge data precipitation Radar estimate Raingauge data

7. JMA Japan MeteorologicalAgency Radar/Raingauge-Analyzed Precipitation ○Calibrated ‘radar estimate’ with raingauge data are more accurate Analyzed precipitation precipitation Calibration factor × Radar estimate Raingauge data

8. JMA JMA Japan MeteorologicalAgency Japan MeteorologicalAgency Radar/Raingauge-Analyzed Precipitation process Qualification of radar data*remove ‘false echo’ like ground clutter Calibration over the entire radar detection range Calibration over land*modification of calibration factor Composition*using maximum value method *replace with raingauge data Radar/Raingauge-Analyzed precipitation

9. JMA Japan MeteorologicalAgency Calibration over the entire radar detection range ○Conditions in calibration （1）calibration factor is a function of beam height and is calculated for each radar every time （2）analyzed precipitation estimates of each radar in the area where multiple radars overlap should be equal （3） analyzed precipitation estimates should be equal to the raingauge precipitation

10. Calibration over the entire radar detection range (1) E1(x,y)=F1(x,y)E0(x,y) F1(x,y)= Fa(x,y)｛1+Fx(x,y)・H(x,y)2｝ calculation of Fx

11. Calibration over the entire radar detection range (2) E1(x,y)=F1(x,y)E0(x,y) F1(x,y)= Fa(x,y)｛1+Fx(x,y)・H(x,y)2｝ calculation of Fa

12. Raingauge precipitation Calibrated estimates JMA Japan MeteorologicalAgency Calibration over land (modification) ① modify calibrated estimates on raingauge grids R(i) = C2(i)×E1(i) R(i) ：raingauge precip. E1(i) ：calibrated estimates C2(i) ：factor to modify estimates ＊for all the raingauge grids of the radar raingauge grid

13. Radar precipitation ・　raingauge grids Calibration over land (modification) ② Determine factors of all grids over land Interpolate factors of raingauge grids to a target grid with weights. ＊weight＊ W(i)=W1(i)×W2(i) W1 (i)： for distance W2 (i)： for rain intensity and beam attenuation ■target grid i : raingauge number ■ factor of a target grid　　　　　＝ ∑W(i)C2(i)

14. Radar/Raingauge-Analyzed Precipitation 1-hour radar precipitation raingauge precipitation

15. Radar/Raingauge-Analyzed Precipitation Radar precipitation Calibrated precipitation

16. Radar/Raingauge-Analyzed Precipitation Composite calibrated radar data

17. JMA JMA Japan MeteorologicalAgency Japan MeteorologicalAgency Flowchart of VSRF process Extrapolation of precipitation with orographic effect(EX6) Merge EX6 and MSM(MRG) VSRF of precipitation up to 6 hours, spatial resolution 1km

18. JMA Japan MeteorologicalAgency Extrapolation method（EX6） ･Extrapolation method is effective up to ~ 3 forecast hours 「extrapolation」 after 1 hour Move it with the same speed and the same direction as it moved. Non-linear extrapolation was introduced in 2006. now before 1 hour

19. JMA Japan MeteorologicalAgency Data used for making VSRF Outputs of Numerical Weather Prediction *MSM(mesoscale model) operation:8 times a day *wind（700･900hPa） *temperature(900hPa) *relative humidity(900hPa) *precipitation(surface) Topography data

20. Precipitation enhanced by orographic effect Pre-existing seeder cloud Feeder cloud Moist low-level flow JMA JMA Japan MeteorologicalAgency Japan MeteorologicalAgency ○Estimate precipitation due to updraft along a mountain ･MSM(900hPa）temperature, wind ･Analyzed precipitation Stationary part of precipitation over mountains caused by *cold air outbreak across the sea *low pressure seeder-feeder model （BrowningandHill，1981）

21. Enhancement and dissipation of precipitation by orographic effect ○enhancement ○dissipation Mountain Low level wind (Pobability of the) Orographic precipitation Movement of a echo Low level wind Orographic enhancement JMA JMA Japan MeteorologicalAgency Japan MeteorologicalAgency

22. Enhancement and dissipation of precipitation by orographic effect (1) Enhancement Precipitable amount by orographic effect Difference caused by orographic effect Without orographic effect With orographic effect

23. Enhancement and dissipation of precipitation by orographic effect (2) Dissipation Difference caused by orographic effect Without orographic effect With orographic effect

24. JMA Japan MeteorologicalAgency Merging method MRG Merging ratio considering space Compare the accuracy of EX6/MSM ○ using pattern distance Merging ratio considering time Increase the ratio of MSM as forecast time goes Merge ○ every 10 minute up to 6 hours

25. JMA Japan MeteorologicalAgency Merging method MRG Compare the accuracy of EX6/MSM ○ using pattern distance Calculate the reliability “r” of MSM○ indicate the merging ratio Calculate the merging ratio R(t) ○ using reliability r and weight function C(t) Merge ○ every 10 minute up to 6 hours

26. Radar/raingauge precipitaion analysis at initial time（upper left） ・EX6 FT=3 of the initial time 3 hours before（lower right） ・latest MSM（lower left） calculate the reliability of MSM comparing the similarity RA MSM EX6

27. ratio of merge considering time reliability of MSM＝0.5 reliability of MSM＝１ FT ratio of EX6 at forecast time the larger the r of MSM, the smaller the ratio of EX6 red line : lower limit of the ratio of EX6 : C(t) Ratio of MSM = r ･{1 － C(t)}

28. JMA JMA Japan MeteorologicalAgency Japan MeteorologicalAgency Examples of VSRF(Merging method) Top left R-A, top right MSM, bottom left EX6, and bottom right MRG at 11JST 31 May 2000 (6-hour forecast). MRG could predict the extending western rain systems. Same as the left figure, at 15JST 31 May 2000(6-hour forecast). MRG could predict isolated convective rain systems.

29. Precipitation Nowcasts Forecast 10 minute precipitation amount up to 60 minutes every 10 minute ※ with extrapolation method res.=1km, forecast every 10min Disseminate within 3 minutes of observation time Previous calibration factors (10 min before) are used. Use the movement derived by VSRF Only dissipation by orographic effect is introduced. 10minutes rainfall initial = 0730JST 06 June 2004

30. JMA Japan MeteorologicalAgency Thank you for your attention!