TITLE: Profiler/Sodar ABLE Sodar Wind Profiles [ABLE]
CONTACTS:
Richard L. Coulter - ER 203
Argonne National Laboratory
9700 South Cass Avenue
Argonne, IL 60439
Voice: 630 252-5833
Fax: 630 252-5498
Email: rl_coulter@anl.gov
1.0 DATA SET OVERVIEW
This data set contains hourly profiles of wind speed and direction from
the the Atmospheric Boundary Layer Experiments (ABLE) Doppler Minisodars
operated by the Argonne National Laboratory in the Walnut River Watershed
in Butler County Kansas (east of Wichita). During the IHOP period three
sodars were in operation. Data cover the period from 13 May to 25 June
2002 The data are in ASCII format.
2.0 INSTRUMENT DESCRIPTION
2.1 Instrumentation
The ABLE minisodar : One of these instruments is placed alongside each of
the RASS wind profilers.
General Purpose
The minisodar measures wind profiles from about 10 m to 200 m above the
surface, thus filling in the gap left below the minimum height of the wind
profilers.
Primary Quantities Measured
The primary quantities measured the the system are the intensity and Doppler
shift of backscattered acoustic energy from index of refraction fluctuations
(created by temperature and wind fluctuations) embedded in the atmosphere.
Detailed Description
List of Components
The minisodar has been developed and fabricated at Argonne National Laboratory
(ANL). It consists of a 32 element array of piezoceramic tweeters mounted
vertically within a protective enclosure roughly 1.5 m X 1.5 m X 1.5 m. The
acoustic "in phase" transmission is reflected off a plate into a vertically
propagating wave. This orientation enables the system to operate in all
weather conditions.
The minisodars operate by transmitting in two different vertical planes and
receiving backscattered energy from refractive index fluctuations moving with
the mean wind. By sampling in the vertical direction and two tilted planes,
the three components of motion can be determined.
The system consists of a single phased array antenna that transmits alternately
along three pointing directions: one vertical, one in the north-south vertical
plane (to the north) and one in the east-west vertical plane (to the east).
The non-vertical beams are tilted about 17 degrees from vertical.
Radial components of motion above each pointing direction are determined
sequentially, separated by about 1.5 seconds. Thus the system repeats its
sequence about every 5 seconds. The data from each transmit pulse are processed
with a FFT centered about each range gate (e.g. every 5 m increment in the
vertical) to determine the mean Doppler shift. The signal-to-noise ratio is
used to determine if each estimate is acceptable. All the acceptable data
within an averaging interval (e.g. 15 minutes) are averaged and combined to
produce a wind profile if there are enough acceptable data points (25%, e.g.)
within the interval.
The averaged data are output in files with format similar to radar wind
profiler (".sod") format for consistency. High resolution radial moments
data and spectra can be produced if desired.
2.2 Station Locations
UTM km (Zone 14)
Site 99 deg Meridan DEG dddmmmsss ddmm.mm Alt (m)
---------------------------------------------------------------------------
Beaumont, KS 4167.1 UTMN km 37.627 37 37' 38" 37 37.64' 478
717.2 UTME km 96.538 96 32' 19" 96 32.32'
Oxford, KS 4126.7 UTMN km 37.273 37 16' 25" 37 16.41' 360
668.8 UTME km 97.095 97 05' 45" 97 05.75'
Whitewater, KS 4189.5 UTMN km 37.841 37 50' 26" 37 51.43' 416
659.6 UTME km 97.186 97 11' 10" 97 11.16'
For file names the station IDs are as follows:
Beaumont be
Oxford ox
Whitewater wh
Topo maps and aerial photos are available at:
gonzalo.er.anl.gov/ABLE/sitelatlon.html
3.0 DATA COLLECTION AND PROCESSING
UCAR/JOSS conducted no processing or quality control on these data.
4.0 DATA FORMAT AND FILE NAMING
4.1 Data Format
These data are in ASCII format.
Note: The sodar wind profile data files
have been converted from their orginal
format to the pop4 format of the 915 MHz
wind profiler data. In doing so some of
the header values are only place holders.
Line Description
---- -----------
1 Instrument
2 Parameter measured
Instrument
3 N. Lat.
W. Long.
Site elevation (m)
4 End date and time of data collection UTC
5 Averaging time (sec)
Number of beams
Number of range gates
6 Samples required for consensus:Total samples (placeholder) (pair for each beam)
7 Null placeholders
8 placeholder
placeholder
Vertical correction for oblique beams (0=N, 1=Y)
placeholder
placeholder
Number of range gates (oblique and vertical)
Spacing between range gates (m) (oblique and vertical)
9 Azimuth and elevation (pair for each beam)
10 Data columns header
11- Range gate height AGL (km)
Wind Speed ( /s)
Wind Direction (deg)
Radial Velocity (vertical and oblique)
Percent of samples returned (vertical and oblique)
Mean SNR (dB) (vertical and oblique)
End $-EOF flag
All times are UTC.
4.2 File Naming conventions
wh_c020608.sod
where:
wh is the station ID (here Whitewater)
02 is the year (2002)
06 is the month (June)
08 is the day of the month
5.0 DATA REMARKS
None.
6.0 REFERNCES
ABLE Home Page: gonzalo.er.anl.gov/ABLE/index.html