NCAR’s Integrated Soundings System NCAR’s Integrated Soundings System and QC Processing with NIMAand 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 / 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