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NCAR’s Integrated Soundings System NCAR’s Integrated Soundings System and QC Processing with NIMAand QC Processing with NIMA
Bill Brown
NCAR/EOL
Steve Cohn, Mike Susedik, Gary Granger
(And in RAL : Larry Cornman, Cory Morse, et al )
Vaisala Wind Profiler Workshop, 9 June 2006
NCAR / EOLNCAR / 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
ISSISS Integrated 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.
Wind Profilers, DBS and MAPRWind 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)
DeploymentsDeployments
UsesUsesBL 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]
CASES99, Kansas
Nauru99, central Pacific
MISSMISS
Mobile ISS
T-REX
Placing Profilers across a valley Placing Profilers across a valley
• MISS can be moved around to study spatial variability
•
MAPR
MISS
NIMANIMA
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
NIMA before after
Cornman et.al., 1998
T-REX Project
Removing RFI
Standard Processing
NIMA Processing
Removing ground clutter
Standard processing
NIMA processing
Date Recovery Rates
NAME (Mexico 2004)
Removes some bad data(here with good sites,removed 4-8 %)
NIMA typically adds 100 - 500 m range
ISS2 Site
Comparison with radiosondes
120 soundings
Classic POP vs sonde
RMS 2.35 m/s
NIMA vs sonde
RMS 1.39 m/s
DBSDBS• “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
MAPRMAPR• 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
MAPR wind measurements (MAPR wind measurements () compared with anemometer ) compared with anemometer measurements (measurements (lineline) on 300 meter BAO tower.) on 300 meter BAO tower.
Similar accuracy to DBS
Std.Dev. 1.5 m/s
3 Month Comparison3 Month Comparison
Correlation coeft R^2 0.8
Standard Deviation 1.3 m/s
60% agree to 1m/s 83% agree to 2m/s
ExampleExample
MAPR and tower observations of an Arctic front
Note the brief updraft (red) in clear-air ahead of the front
30 second MAPR winds
MAPR compared with MAPR compared with conventional DBS profilersconventional DBS profilers
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)
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
FDI – RIMFDI – 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)
RIM cf FMCW & Sonde (IHOP)RIM cf FMCW & Sonde (IHOP)MAPR Std Mode 100m
MAPR RIM Mode 20m
• RIM reflectivity similar to FMCW• RIM winds similar to soundings
T-Y. Yu & W. Brown, 2005
U.Mass. FMCW 10m
Small RollsSmall Rolls
U.Mass. FMCW (S-Band)
Stephen Frasier (U.Mass.)
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 …
Small Rolls - RIM Small Rolls - RIM VelocityVelocity
Stronger winds aloft
Correlation in vertical velocity and winds :
- Downdraft leading edge
- Gusts with downdrafts, mixing down of wind aloft
15 Second Wind Vectors
ConclusionsConclusions 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