1. Status of Dual-Doppler Wind Retrieval Project Carpe Diem 6 th Meeting Helsinki 24 June 2004 by Kheng University of Essex

2. Recall in Dublin ● What we have done – Shown visualisation examples produced by DARWIn – Converted Polar data -> Cartesian – Successfully constructed 3D wind fields – Shown 2 case studies

3. Coordinates conversion II

4. Case I (17 Dec 2002) 1915hr : Dual-Doppler Wind Field

5. Case Studies - Case I : (17 Dec 2002) 1915hr - Case II : (15 Aug 2003) 1815 hr

6. Case I (17 Dec 2002) 1915hr : Gattatico Doppler Velocity

7. Case II (15 Aug 2003) 1815hr : Dual Doppler Wind Field

8. Remarks from Dublin meeting ● Problems & comments – Limited data sets – How to verify validity of the constructed 3D wind fields. – Triple Doppler retrieval – Comparison with NWP model

9. New data sets ● 2003 July 13 – 14 – Bologna, Gattatico, scan time (00, 12, 15, 27, 30...) ● 2003 July 31 – Bologna, Gattatico, Teolo ● 2003 September 09 – Bologna, Gattatico ● 2003 November 11 – Bologna, Gattatico, Teolo

10. Case 1: (2003 Jul 13) 2330 hr 3.2 o PPI – Reflectivity Gattatico Bologna

11. Case 1: (2003 Jul 13) 2330 hr 3.2 o PPI – Doppler Velocity Bologna Gattatico

12. Case 1: (2003 Jul 13) 2330 hr 3.2 o Wind Field

13. How do we know that the wind field is correct?

14. Numerical procedures ● Iterative method: – horizontal components – vertical component ● Boundary conditions: – zero velocity on ground ● Typical convergent factor

15. Comparison of reconstructed radial velocity field and radar measurement measurement reconstruction Gattatico Bologna

16. “along-track” components r1r1 r2r2 r 12 v. (r 12 + r 2 – r 1 ) = 0  = v (cal).r 12 + v r2 (obs) r 2 – v r1 (obs) r 1 Typical relative deviation,  /(v.r 12 ) < ±1% v

18. Case 2: (2003 Jul 31) 1734 hr 3.1 o PPI – Gattatico ZDRReflectivity

19. Case 2: (2003 Jul 31) 1734 hr 3.1 o PPI – Gattatico ZDR Reflectivity

20. Case 2: (2003 Jul 31) 1734 hr 3.1 o PPI – Bologna ZDRReflectivity

21. Case 2: (2003 Jul 31) 1734 hr 3.1 o PPI – Bologna ZDR Reflectivity

22. Possibility of performing triple- Doppler analysis? we are still trying because of...

23. Case 2: (2003 Jul 31) 1730 hr 2.5 o PPI – Teolo Doppler velocity Reflectivity

24. Case 2: (2003 Jul 31) 1730 hr PPI – Doppler Velocity Teolo 2.5 o Gattatico 3.1 o

25. Case 2: (2003 Jul 31) 1730 hr PPI – Doppler Velocity Teolo 2.5 o Gattatico 3.1 o

26. Problems with Triple-Doppler ● Teolo – many rays are missing ● Teolo – Doppler radial velocity convention ● Teolo – 470 m asl, lowest elevation 0.9 deg – Minimun height ~ 1400 m (centre) ● Gattatico & Bologna – ? m asl, lowest elevation 0.5 deg – Minimun height ~ 600 m (centre) – Next elevation ~ 1400 m (centre)

27. Case 3: (2003 Sep 09) 1315 hr 2.3 o PPI – Reflectivity Gattatico Bologna

28. Case 3: (2003 Sep 09) 1315 hr 2.3 o PPI – Doppler Velocity Gattatico Bologna

29. measurement reconstruction Case 3: (2003 Sep 09) 1315 hr 2.3 o PPI – Radial Velocity Comparison Gattatico Bologna

30. Case 3: (2003 Sep 09) 1315 hr 3D wind field

31. Case 4: (2003 Nov 11) 0349 hr 2.3 o PPI – Reflectivity Gattatico Bologna

32. Case 4: (2003 Nov 11) 0349 hr 2.3 o PPI – Doppler Velocity (folding problem) Gattatico Bologna

33. Case 4: (2003 Nov 11) 0349 hr 4.8 o PPI – ZDR (bright band)

34. Case 4: (2003 Nov 11) 0350 hr 2.5 o PPI – Teolo Doppler velocity Reflectivity

35. measurement reconstruction Case 4: (2003 Nov 11) 0345 hr 1.4 o PPI – Radial Velocity Comparison Gattatico Bologna

36. Case 4: (2003 Nov 11) 0345 hr Wind Field

37. Comparison with NWP model? a CD with radar data has been sent to SMHI and wind field information of several cases have been made available for comparison...

38. Conclusion ● Analysed a few more new cases. ● All the derived wind fields have been checked by comparing with original measurement and calculating relative deviation of “along-track” component. ● Made initial attempts on triple-Doppler analysis, but need more time to understand Teolo data.