Campbell IRGASON, Руководство по эксплуатации продукта

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The non-orthogonal wind speed components are then transformed into orthogonal wind speed
components, u
x
, u
y
, and u
z
, with the following:
Eq. 4
where A is a 3 x 3 coordinate transformation matrix, that is unique for each CSAT3 and is stored in
ROM memory.
11.1.2 Temperature
The sonically determined speed of sound can be found from the sum of the inverses of Eq. 1 (p.
54) and Eq. 2 (p. 54). The CSAT3 corrects online for the effect of wind blowing perpendicular to
the sonic path. No additional off-line corrections are required as suggested by Liu et al., 2001.
Eq. 5
The speed of sound in moist air is a function of temperature and humidity and is given by:
Eq. 6
where:
g
= ratio of specific heat of moist air at constant pressure to that at constant volume,
P = pressure,
r = air density,
R
d
= gas constant for dry air,
T
v
= virtual temperature,
T = air temperature, and
q = specific humidity defined as the ratio of the mass of water vapor to the total mass of air
(Kaimal and Gaynor, 1991; Wallace and Hobbs, 1977).
Note that
g
is a function of specific humidity. It would be convenient if the effects of humidity
could be consolidated into one term.
The specific heats for moist air at constant pressure and volume are given by:
Eq. 7
IRGASON® Integrated CO
2
/H
2
O Open-Path Gas Analyzer and 3D Sonic Anemometer 55