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CARPE DIEM FMI (Partner 5) progress report

CARPE DIEM FMI (Partner 5) progress report. Jarmo Koistinen , Heikki Pohjola Finnish Meteorological Institute. Work Packages. Area 1/WP3: Development of a variational assimilation scheme for Doppler winds (FMI+SMHI, responsible persons at FMI Heikki Järvinen, Kirsti Salonen).

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CARPE DIEM FMI (Partner 5) progress report

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  1. CARPE DIEMFMI (Partner 5) progress report Jarmo Koistinen, Heikki Pohjola Finnish Meteorological Institute

  2. Work Packages • Area 1/WP3: Development of a variational assimilation scheme for Doppler winds (FMI+SMHI, responsible persons at FMI Heikki Järvinen, Kirsti Salonen). • Area 2/WP7: Advanced surface radar-based precipitation estimate applying NWP data (FMI, Jarmo Koistinen, Heikki Pohjola).

  3. Objective: Improve the accuracy of operational precipitation measurements 1(2)

  4. National End User Meeting in Feb. 2003 1. Finnish Road Authority Applies observed and nowcast distributions of rain, sleet and snow for road operations (snow clearing and salting costs ~100 M euros/winter). 2. Kemijoki hydroelectric power company See the presentation of Hannu Puranen. 3. FMI Continuous need to improve radar products (we are working in the Operative Services).

  5. Better accuracy with integrated data • Existing: Hydrometeor phase analysis (rain, sleet, snow) based on surface data (T,RH). Resolution 5 min & 1 km.Time-space variable Z – R / Ze – S relations. • New from CARPE DIEM: apply a NWP model (HIRLAM) to obtain 3D hydrometeors.

  6. WP 7.1: Attenuation correction based on 3D water phase diagnosis from NWP model quantities (single polarisation). Deliverables: • Diagnosis of hydrometeor water phase in 3D radar volumes based on NWP model fields. • Large attenuation statistics for rain only (assumed in most existing radar systems) compared to variable hydrometeor phase statistics. • Improvement in surface precipitation estimates.

  7. An axample of severe C-band attenuation

  8. WP 7.1: Attenuation correction based on 3D water phase diagnosis from NWP model quantities (single polarisation). Work started in spring 2003: • Software to read 3D HIRLAM real time fields from the FMI database into the 3D radar composite grid partly ready (see the manual slides by Harri Hohti). • Hail algorithm (POH) implemented (see separate manual slides by Harri and Markus Peura).

  9. WP 7.2: Elimination of overhanging precipitation (OP) from surface estimates Altostratus 19 % of all VPR in Finland

  10. WP 7.2: Rejection of overhanging precipitation (OP) from surface estimates Deliverables: • 1D diagnosis of OP from polar volumes above each radar (see WP 7.3). • 3D diagnosis of OP from NWP fields between radar sites. • Integrated radar-NWP correction method to reject OP from the network products. Work done: • 1D diagnosis ready, 3D HIRLAM fields can be read.

  11. WP 7.3:Vertical reflectivity profile (VPR) correction applying radars and NWP • Deliverables: • Automatic classification of VPR above each radar based on radar, soundings and NWP. • Automatic quality control of each measured VPR. • Operational VPR correction in a network of 7 radars.

  12. Vertical Profile of Reflectivity (VPR) • Measured VPR • 7 radars • every 15 minutes • layer thickness 200 m • range 2 - 40 km • max bin count 5000 / layer 3D polar volume 1(2)

  13. Classification and QC of each VPR • representativity • rain • bright band • snow • clutter • clear air echo • overhanging precipitation • unphysical gradient Statistics Freezing level (FL) from radio soundings (soon: from HIRLAM also) Climatological profile adjusted to freezing level Reference dBZ at ground level (green dot in VPR) Calculation of the correction 1(2)

  14. Examples of classified VPR´s Overhanging precipitation • Main parameters in profile recognition: • Height • Intensity • Gradients (dBZ/km) • Freezing level 1(2)

  15. Clear air echo and clutter Evaporation and clutter 1(2)

  16. Rain and bright band Snow 1(2)

  17. Climatological profile Bright band at ground, sleet 1(2)

  18. Profile representativity 1(2)

  19. Statistics of VPR from March 2001 to February 2002 (234 908 profiles) 1(2)

  20. Precipitation top heightMar 2001 – Feb 2002 1(2)

  21. VPR correction 1(2)

  22. Profile correction for 500 m PsCAPPI Snow 1(2)

  23. Rain Profile correction 1(2)

  24. Bright band at ground Profile correction 1(2)

  25. Climatological profile Profile correction 1(2)

  26. Time averaging of the single radar VPR correction 1(2)

  27. VPR correction in the network 1(2)

  28. 24 h accumulated precipitation Nov 7, 2002, 14 UTC No VPR correction With VPR correction 1(2)

  29. 24 h accumulated precipitation Nov 8, 2002, 23 UTC No VPR correction No VPR correction 1(2)

  30. 24 h accumulated precipitation Dec 21, 2002, 21 UTC No VPR correction VPR correction 1(2)

  31. Yearly average VPR correction 1(2)

  32. Validation of the VPR correction 1. With rain gauges 2. With overlapping radars 1(2)

  33. 1(2)

  34. Validation of VAN VPR correction with ANJ data (distances 130-150 km) • Only precipitation cases included (dBZ>10 and ANJ profile classified as precipitation). • Length of validation period 13 months (other radar pairs 2 months, not shown). • Blue: non-corrected ANJ-VAN (dB) • Red: VPR correction performed for VAN data, ANJ-(VAN+correction), (dB). Correction applies both measured and climatological VPR at VAN. • Black: VPR correction performed for VAN data applying only climatological profiles.

  35. Future development of the VPR correction • Diagnosis and rejection of OP prior to the VPR correction WP 7.2). • Improved climatological profile (now overcorrecting). • Use of freezing level height from HIRLAM model and simulated VPR (at least comparison of measured and NWP profiles). • More validation, also with gauges. • Fully operational in all FMI products in 2003 even without OP-correction (End User requirement).

  36. Dissemination of the results • Operational FMI products, feedback from End Users and other customers • CARPE DIEM and related EU-projects • Textbook (eds. Meischner et al.) • Peer reviewed papers • AMS Radar Conference • 3rd GPM Workshop • ERAD 2004 • BALTEX/CEOP, NORDRAD, OPERA

  37. Monthly classified VPR´s from Mar 2001 to Feb 2002 1(2)

  38. Precipitation top heightMarch 2001 (snow) 1(2)

  39. Precipitation top heightJuly 2001 (rain) 1(2)

  40. Bright band heightMar 2001 – Feb 2002 1(2)

  41. Bright band amplitudeMar 2001 – Feb 2002 1(2)

  42. Snow and clutter Profile correction 1(2)

  43. Rain Profile correction 1(2)

  44. Rain Profile correction 1(2)

  45. Rain Profile correction (no cutter) 1(2)

  46. Profile correction (no extrapol.) Bright band at ground 1(2)

  47. Magnitude of the VPR correction at various ranges March 2001 – February 2002 1(2)

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