May 15, 2014

POINT OF CONTACT

Principle investigator:
     Kirk L. Clawson
     NOAA Air Resources Laboratory Field Research Division
     1750 Foote Dr.
     Idaho Falls, ID 83402
     Kirk.Clawson@noaa.gov
     (208) 526-2742

README.TXT - Description of Data Files from SoDARs Located within the Tracer Sampling Array

Two sodars were deployed on the tracer dispersion grid during PSB1. The height range and 
resolution during PSB1 were set at 30 to 200 m and at 10 m, respectively. An Atmospheric 
Systems Corporation ASC4000 minisodar was located at a permanent site at about 800 m arc 
distance, 57 degrees arc angle. Another minisodar, an Atmospheric Research & Technology (ART) 
model VT-1, was deployed during PSB1. It was located at about 3200 m arc distance and
44.5 degrees arc angle near the 10 m meteorological station (TOW) and the R2 sonic anemometer. 
Data from the ASC4000 was averaged at 10-minute intervals, recorded on a Campbell Scientific 
CR23X data logger every 5 minutes, and transmitted by radio link back to the ARLFRD office. 
Data from the VT-1 was averaged at 10-minute intervals and stored on both primary and backup 
drives on site. Computer times on the minisodars were regularly checked and synched to the 
official internet time.   

Power was supplied to the batteries servicing the sonic anemometer (R2), ART VT-1 sodar, and 
TOW near the center of the 3200 m arc using a large trailer-mounted solar panel array. This 
solar array experienced problems in providing adequate charge to the batteries during the 
experimental period and had largely failed by the end of the experiment. As a consequence, 
some data during the IOPs was lost from the ART VT-1 sodar (IOP5). Power to the ASC4000 was 
supplied by AC line power.

Data was automatically screened for acceptance or rejection by internal algorithms using 
criteria based primarily on signal-to-noise ratio and number of acceptable values during the 
averaging period. Rejected data were specified as missing values. The ASC data screening 
algorithm was proprietary while the ART screening algorithm could be configured. ARLFRD used 
the software program called SodarView for the ASC and the software program Data Manager for 
the ART for data review, analysis, and display.

The wind speed and direction data sets for the ASC and ART sodars were plotted and reviewed 
by the data analyst for consistency and accuracy by comparing results with other measurements 
for the duration of each test plus one hour before and after each test.  This included all 
wind speed and direction measurements in the horizontal at 30 m (sonic G1 on GRI, COC at 
30 m), 40 m (45 m on GRI, sonic G2 on GRI), 60 m (GRI), and with the radar wind speed profiler 
(PRO) at 160 m, where available. All of the comparisons were good with the exception of PRO 
at 160 m which appeared to have a low wind speed bias relative to the sodars.

Five files for the ASC4000 sodar are included in the PSB1 project database, one for each 
of the IOP test days. Each file contains 10-minute averages covering the 24-hour period of 
the data record. The files are designated Grid3sodar_PSB1_IOP#_Oct**.csv where # 
specifies the IOP test number and ** specifies the date in October. The times listed are 
MST (hh:mm:ss) for the start time of the 10-minute averaging period. The notation in the 
column headers follows: ws = wind speed, wd = wind direction, w = mean vertical wind speed, 
sdw = standard deviation in w, sdu = standard deviation in u, sdv = standard deviation in v, 
tempC = temperature in degrees C. Wind speeds and standard deviations are in units of m/s and 
the wind direction is in degrees. The number following (30, 40,...) is the height of the 
measurement in meters. Missing values are designated by 9999 for wind direction and 99.99 
for everything else. The sodar's internal algorithms determined which points were missing.  
No further processing was done.

Five files for the ART VT-1 sodar are included in the PSB1 database, one for each of the
IOP test days. While there were power supply problems for the ART VT-1, these did not occur 
during any of the actual IOPs. The files are named Arc3200sodar_PSB1_IOP#_Oct**.csv where 
# specifies the IOP test number and ** specifies the date in October. The times listed 
are MST for the start time of the 10-minute averaging periods. The notation in the column 
headers follows: WS = wind speed, WD = wind direction, WSPD = mean vertical wind speed (w), 
WSD = standard deviation in w, VSD = standard deviation in v, and USD = standard deviation 
in u. Wind speeds and standard deviations are in units of m/s and the wind direction is in 
degrees. The number following (30, 40,...) is the height of the measurement in meters. 
Missing values are designated by -999 for wind direction, -99.9 for u and v wind speeds, 
-9.99 for w wind speed, and 99.9 for the standard deviations. Standard deviations are 
zero if wind speed data is missing.
