1. © 2003 University of Essex Progress of Dual Doppler Radar Visualisation Software DARWIn ( Doppler Analysis and Retrieval of Wind Information ) Yong Kheng Goh kygoh@essex.ac.uk http://prswww.essex.ac.uk 15-16 December 2003

2. © 2003 University of Essex Contents Part I : - Status of DARWIn Part II : - Case studies

3. © 2003 University of Essex Status of Software - Reading SMR data (Bologna & Gattatico) - Graphics generation:  2-D Visualisation: PPI, RHI, VAD  3-D Visualisation: Velocity vectors - Data Conversion: polar -> Cartesian - Construction of wind velocity vectors - Saving retrieved wind vectors in ASCII file

4. © 2003 University of Essex Reading SMR data sets - Available data set:  15 Aug 2003 (1400 - 1857)  17 Dec 2002 (1800 - 2357) - Data Quality:  Weak Z in region of interest  SPC Radar Scan problems (Aug 2003 case)  GAT Radar Time problems (both cases)

5. © 2003 University of Essex Visualisation I

6. © 2003 University of Essex Visualisation II

7. © 2003 University of Essex Visualisation III

8. © 2003 University of Essex Visualisation IV

9. © 2003 University of Essex Visualisation V

10. © 2003 University of Essex Visualisation VI

11. © 2003 University of Essex Coordinates conversion I - Grid resolution:  0.5 km x 0.5 km (x ~1 km) - Ray resolution:  Spacing 0.25 km  beam width 0.9 deg  approx. 1 km width - Algorithm:  trap and average

12. © 2003 University of Essex Coordinates conversion II

13. © 2003 University of Essex Wind Extraction : Algorithm - Horizontal components  data: radial velocity from 2 radars  Vr = u sin(az) cos(el) + v cos(az) cos(el) + W sin(el)  W = Wt + w, Wt = 2.6 Z 0.107 - Vertical component  Mass continuity equation  Boundary conditions 

14. © 2003 University of Essex Wind Extraction : boundary conditions - Currently using V = 0, on ground - What boundary condition do we want to use? - Any other information available?  Wind vector at 10 m

15. © 2003 University of Essex Wind Field Data Structure - Header lines:  location of grid center  date/time  data files name - Data:  6 columns  x, y, z, Vx, Vy, Vz

16. © 2003 University of Essex Case Studies - Case I : (17 Dec 2002) 1915hr - Case II : (15 Aug 2003) 1815 hr

17. © 2003 University of Essex Case I (17 Dec 2002) 1915hr : Gattatico Reflectivity

18. © 2003 University of Essex Case I (17 Dec 2002) 1915hr : Bologna Reflectivity

19. © 2003 University of Essex Case I (17 Dec 2002) 1915hr : Gattatico Doppler Velocity

20. © 2003 University of Essex Case I (17 Dec 2002) 1915hr : Dual-Doppler Wind Field

21. © 2003 University of Essex Case I (17 Dec 2002) 1915hr : RHI along Radar-to-Radar line

22. © 2003 University of Essex Case I (17 Dec 2002) 1915hr : Dual-Doppler Wind vs. VAD

23. © 2003 University of Essex Case II (15 Aug 2003) 1815hr : Bologna Reflectivity

24. © 2003 University of Essex Case II (15 Aug 2003) 1815hr : Bologna Reflectivity

25. © 2003 University of Essex Case II (15 Aug 03) 1815hr : Gattatico Reflectivity

26. © 2003 University of Essex Case II (15 Aug 2003) 1815hr : Bologna Doppler Velocity

27. © 2003 University of Essex Case II (15 Aug 2003) 1815hr : Dual Doppler Wind Field

28. © 2003 University of Essex What next... ? - More data for analysis - Extracting vertical wind component - Testing + verifying DARWIn (Cedric) - Extraction of clear- air wind - Comparison with NWP - Triple Doppler?

29. © 2003 University of Essex Summary ● DD-VAD Analysis -- RHIs show Bologna Radar can have problems. ● Conversion -- demonstrates the quality of the polar->cartesian conversion. ● 3-D wind field -- examples of retrieved data and problems with boundary conditions. ● Verifying results -- any other info available?