Technical Interchange Meeting – ROC / NSSL / NCAR

1. Technical Interchange Meeting – ROC / NSSL / NCAR Real-time time-series implementation of the Radar Echo Classifier (REC)for clutter detection in ORDA Mike Dixon NCAR ROC / NSSL / NCAR TIM Boulder CO 11 May 2005

2. The goal was to develop and test a version of the REC with the following properties: Fast and efficient for real-time operation, suitable for use in the ORDA. Works with time series data, so that the algorithm has access to the spectral domain. Is suitable for detecting clutter and AP. Goal

3. This implementation of the REC was developed to handle time-series data in LIRP format. It was tested on the following data sets: KJIM, stratiform situation, non-phase-coded. SPOL at Boulder, phase-coded. SPOL at NAME, Mexico, non-phase-coded, alternating-pulse dual-polarization. Data sets

4. Kernel: 5 deg wide, 2 km along the beam; Uses the following fields: TDBZ - DBZ texture: squared change in dBZ from one gate to the next, in range, averaged over the kernel; SPIN - DBZ ‘spin’: measure of how frequently the trend in reflectivity along a beam changes with range. Averaged over the kernel. VEL: velocity at the gate. SDVE: standard deviation of velocity over the kernel. WIDTH: spectrum width at the gate. CLUTPROB: clutter probability, based on ratios of power near 0 m/s to power in rest of spectrum. REC for clutter or AP detection

5. 1 WIDTH 0 0 3.2 1 TDBZ 0 0 45 1000 1 SDVE 0 0 0.7 1 SPIN 0 0 50 100 Membership functions 1 VEL 0 -2.3 0 2.3 1 CLUTPROB 0 0 3 15

6. Non-phase-coded data Stratiform rain to NW Ground clutter KJIM Case

7. KJIM dBZ

8. KJIM Vel

9. KJIM WIDTH

10. KJIM TDBZ

11. KJIM SPIN

12. KJIM SDVE

13. KJIM Clutter Probability

14. KJIM REC

15. KJIM Clutter FLAG

16. KJIM dBZ

17. KJIM dBZ filtered

18. KJIM VEL

19. KJIM VEL filtered

20. KJIM WIDTH

21. KJIM WIDTH filtered

22. KJIM filter everywhere

23. KJIM dBZ

24. KJIM dBZ filtered everywhere

25. KJIM vel

26. KJIM vel filtered everywhere

27. SZ864 decoding Strong mountain ground clutter Convective weather situation SZ Case - SPOL

28. SZ dBZ

29. SZ VEL

30. SZ WIDTH

31. SZ Trip flags

32. SZ TDBZ

33. SZ SPIN

34. SZ SDVE

35. SZ REC

36. SZ REC FLAG

37. SZ dBZ

38. SZ dBZ filtered

39. SZ VEL

40. SZ VEL filtered

41. SZ WIDTH

42. SZ WIDTH filtered

43. SZ Clutter found

44. Alternate-pulse dual polarization Strong ground clutter Some sea clutter at times Convective weather situation Dual Polarization Case – SPOL at NAME

45. The following fields were added to the REC for the dual polarization case: RHOHV – value at the gate. SD-ZDR – standard deviation of ZDR in range, computed for the single beam only, no azimuth averaging. SD-RHOHV – standard deviation of RHOHV in range, computed for the single beam only, no azimuth averaging. Additional REC fields for Dual Pol

46. 1 SD-ZDR 0 0 2 3 1 SD-RHOHV 0 Membership functions – Dual Pol 1 RHOHV 0 0 0.8 0.95 0 0.02 0.03

47. Dual-pol dBZ

48. Dual-pol VEL

49. Dual-pol WIDTH

50. Dual-pol TDBZ