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Technical Interchange Meeting – ROC / NSSL / NCAR

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.

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Technical Interchange Meeting – ROC / NSSL / NCAR

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  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. Beam 1 Beam 2 Beam3 Beam 4 Beam 5 ComputeMoments ComputeMoments ComputeMoments ComputeMoments ComputeMoments ComputeREC FilterClutter Beam processing sequence IN Out Beam Queue FilteredMoments out

  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. 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, convective situation, phase-coded. SPOL at NAME, Mexico, convective situation, non-phase-coded, alternating-pulse dual-polarization. Data sets

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

  8. KJIM dBZ

  9. KJIM Vel

  10. KJIM WIDTH

  11. KJIM TDBZ

  12. KJIM SPIN

  13. KJIM SDVE

  14. KJIM Clutter Probability

  15. KJIM REC

  16. KJIM Clutter Flag

  17. KJIM dBZ

  18. KJIM dBZ filtered

  19. KJIM VEL

  20. KJIM VEL filtered

  21. KJIM WIDTH

  22. KJIM WIDTH filtered

  23. KJIM filter everywhere

  24. KJIM dBZ

  25. KJIM dBZ filtered everywhere

  26. KJIM vel

  27. KJIM vel filtered everywhere

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

  29. SZ dBZ

  30. SZ VEL

  31. SZ WIDTH

  32. SZ Trip flags

  33. SZ TDBZ

  34. SZ SPIN

  35. SZ SDVE

  36. SZ REC

  37. SZ REC Clutter Flag

  38. SZ Clutter found

  39. SZ dBZ

  40. SZ dBZ filtered

  41. SZ VEL

  42. SZ VEL filtered

  43. SZ WIDTH

  44. SZ WIDTH filtered

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

  46. 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

  47. 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

  48. Dual-pol dBZ

  49. Dual-pol VEL

  50. Dual-pol WIDTH

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