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NCAR’s Integrated Soundings System and QC Processing with NIMA

NCAR’s Integrated Soundings System and QC Processing with NIMA. Bill Brown NCAR/EOL wbrown@ucar.edu. Steve Cohn, Mike Susedik, Gary Granger (And in RAL : Larry Cornman, Cory Morse, et al ). Vaisala Wind Profiler Workshop, 9 June 2006. NCAR / EOL.

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NCAR’s Integrated Soundings System and QC Processing with NIMA

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  1. NCAR’s Integrated Soundings System and QC Processing with NIMA Bill Brown NCAR/EOL wbrown@ucar.edu Steve Cohn, Mike Susedik, Gary Granger (And in RAL : Larry Cornman, Cory Morse, et al ) Vaisala Wind Profiler Workshop, 9 June 2006

  2. NCAR / EOL National Center for Atmospheric Research Earth Observing Laboratory Conducts field projects for the National Science Foundation (NSF) and NSF funded university researchers Large range of equipment (aircraft, lidars, flux arrays, weather radar, radiosondes) including 5 UHF wind profilers

  3. ISSIntegrated Sounding System • The ISS combines various measurement systems: • balloon-borne radiosonde sounding • enhanced surface observation station • 915 MHz Doppler wind profiler • Radio-Acoustic Sounding System (RASS) • Data is archived, displayed, and transmitted to remote analysis stations using a Unix workstation.

  4. Wind Profilers, DBS and MAPR • 915 MHz Profiler Radars (derived from LAP3000) • DBS Doppler Beam Swinging • MAPR Multiple Antenna Profiler Radar • RASS Radio Acoustic Sounding System • EOL has 5 wind profilers UHF (915 MHz / 30 cm) Boundary Layer profilers Echoes from rain/snow and clear air (turbulence, temperature inversions)

  5. Deployments

  6. Uses BL Properties:Inversions (Reno 94/02); Chemistry/Zi/trajectories (PROPHET-00/01); Stable BL (Cases99); Forrest (FABL-99); LLJ (CASES97/JETEX); CBL (Flatland/LIFT-96); Cumulus (SCMS-95); H2O (IHOP); waves and turbulence (Sierra Rotors) Winter Weather, Precipitation, Aviation Safety: Snow/crystals (ISPA 2001/2002); winter storms (IMPROVE-01); winds/fluxes (Transitions-00/Alaska); Airport safety/turbulence (Juneau-96; Lantex-94; T-REX/04) Tropical/Oceanic:Nauru99 (winds/heat flux); TOCS-97 (Zi/winds); FASTEX (1997) (winds/storms); ACE-1(95) (winds); Toga COARE (1992-93) Lake Effects: Lake MI influence/precip (LakeIce-97); Lake Breeze (LABEX-95, Lake Okeechobee) Education: Hands-on teaching, lectures, and research [Reno Basin Inversion (1994); Prophet 2000 and Prophet 2001; Reno-2002]

  7. CASES99, Kansas Nauru99, central Pacific

  8. MISS Mobile ISS T-REX

  9. Placing Profilers across a valley MAPR • MISS can be moved around to study spatial variability MISS

  10. NIMA • NIMA : NCAR Improved Moment Algorithm • Developed in RAP by Larry Cornman, Cory Morse, Kent Goodrich, and others • Uses fuzzy logic to identify good and bad features in Doppler spectra • Removes RFI, ground clutter, and birds • Produces confidence measures

  11. NIMA before after Cornman et.al., 1998

  12. T-REX Project Removing RFI Standard Processing NIMA Processing

  13. Removing ground clutter Standard processing NIMA processing

  14. Date Recovery Rates NAME (Mexico 2004) Removes some bad data (here with good sites, removed 4-8 %) NIMA typically adds 100 - 500 m range

  15. ISS2 Site Comparison with radiosondes 120 soundings Classic POP vs sonde RMS 2.35 m/s NIMA vs sonde RMS 1.39 m/s

  16. DBS • “Regular” wind profiler, standard technique • LAP3000 design • points (“swings”) beam in 3 or 5 directions and uses Doppler to estimate wind component • antenna electronically steered • wind measurement every 15-30 minutes • EOL has 4 DBS profilers

  17. MAPR • Advanced wind profiler developed at EOL • Highly modified DBS profiler • Uses spaced antenna technique • Antenna subdivided in 4 • Track motion over radar • Wind measurement every 1 – 5 minutes

  18. MAPR wind measurements () compared with anemometer measurements (line) on 300 meter BAO tower. Similar accuracy to DBS Std.Dev. 1.5 m/s

  19. 3 Month Comparison Correlation coeft R^2 0.8 Standard Deviation 1.3 m/s 60% agree to 1m/s 83% agree to 2m/s

  20. Example MAPR and tower observations of an Arctic front Note the brief updraft (red) in clear-air ahead of the front 30 second MAPR winds

  21. MAPR compared with conventional DBS profilers • Advantages • MAPR can make a much faster wind measurement • MAPR provides continuous measurements • MAPR does not need mechanical phase switches • PIRAQ digital receivers allow flexible data collection and new experiments to be tested • Disadvantages • MAPR requires 4 antenna/receiver chains • Data analysis more sophisticated (ie, complicated) • Less experience, few systems - algorithms not well developed • Less sensitivity so more powerful transmitter required (DBS 500W, MAPR 4KW)

  22. FDI – RIM FDI : Frequency Domain Interferometry Change in wavelength produces change in phase proportional to range Allows precise measurement of range RIM : Range IMaging Series of wavelength changes Echoes  FFT/Capon transform  Reflectivity(range)

  23. RIM cf FMCW & Sonde (IHOP) MAPR Std Mode 100m MAPR RIM Mode 20m U.Mass. FMCW 10m • RIM reflectivity similar to FMCW • RIM winds similar to soundings • T-Y. Yu & W. Brown, 2005

  24. Small Rolls • MAPR Standard Mode does not see small rolls (about 200m diameter) • RIM Mode Image • does resolve rolls • But : • Not as clear as FMCW • May have ringing • However : • - Can get velocity … U.Mass. FMCW (S-Band) Stephen Frasier (U.Mass.)

  25. Small Rolls - RIM Velocity Stronger winds aloft Correlation in vertical velocity and winds : - Downdraft leading edge - Gusts with downdrafts, mixing down of wind aloft 15 Second Wind Vectors

  26. Conclusions • Profilers Wide range of studies Highly requested by the scientific community • MISS - Mobility very useful • NIMA great tool for cleaning up our data • MAPR - high resolution in time and range

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