Campbell Scientific Open Path Eddy Covariance (OPEC) - Manual (Page 15)

OPEC Open-Path Eddy-Covariance System
To enter the “sonic_azimuth” using the datalogger keyboard, press the
key until the Campbell Scientific Inc. logo is visible in the upper left hand
corner of the display. Press the key. Select the menu “Sonic_Azmth”
ell Scientific
To enter the “sonic_azimuth” using LoggerNet, connect to the datalogger with
enter the
press the key.
and press the key. Enter the azimuth of the negative x-axis and press
the key. Press the several times so that the Campb
logo if visible.
LoggerNet and display the Public data table. Locate the variable
“sonic_azimuth” and click on it. Double click on the number field,
negative x-axis azimuth and
Don’t forget to account for the magnetic declination at the site;
see Appendix A for details.
FIGURE 3-1 and FIGURE 3-2 show the orientation of an IRGASON azimuth
bearing of 140 degrees, e.g., the negative x-axis i
s pointing into 140 degrees.
If the wind is blowing into the sonic, from the negative x-axis to the positive x-
axis (from the transducers to the block), the horizontal wind vector angle
(wind_dir_csat3) is 0 degrees (wind vector) and the compass wind direction
(wnd_dir_compass) is 140 degrees (wind vane).
North
Y
X
Wind Vane
Wind Vector
FIGURE 3-1. IRGASON right hand coordinate system, horizontal wind
vector angle is 0 degrees
NOTE
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