Campbell Scientific EC150 CO2 and H2O Open-Path Gas Analyzer and EC100 Electronics with Optional CSAT3A 3D Sonic Anemometer - Manual (Page 17)

EC150 CO
2
/H
2
O Open-Path Gas Analyzer
The EC100 electronics module digitizes and process the detector data (along
with ancillary data such as ambient air temperature and barometric pressure) to
give the CO
2
and H
2
O density for each chopper wheel revolution (50 Hz). This
high measurement rate is beneficial when there is a need to synchronize the gas
measurements with additional sensors measured by the datalogger. To prevent
aliasing, measurements are filtered to a bandwidth that is specified by the user.
5. Specifications
5.1 Measurements
To compute carbon dioxide and water vapor fluxes using the eddy-covariance
method, the EC150 and a sonic anemometer measure:
• Absolute carbon dioxide density (mg·m –3 )
• Water vapor density (g·m –3 )
• Three-dimensional wind speed (m·s –1 ; requires the CSAT3A)
• Sonic air temperature (°C; requires the CSAT3A)
• Air temperature (°C; requires an auxiliary temperature probe)
• Barometric pressure (kPa; requires an auxiliary barometer)
These measurements are required to compute carbon dioxide and water vapor
fluxes using the:
• Standard outputs:
o CO
2
density, H
2
O density
o Gas analyzer diagnostic flags
o Air temperature
o Air pressure
o CO
2
signal strength
o H
2
O signal strength
• Additional outputs from auxiliary instruments:
o u
x
, u
y
, and u
z
orthogonal wind components (requires the
CSAT3A)
o Sonic temperature (requires the CSAT3A, and is based on the
measurement of c, the speed of sound)
o Sonic diagnostic flags (from the CSAT3A)
Datalogger Compatibility: CR1000
CR3000
CR5000
Measurement
Rate: 100 Hz
Output bandwidth ii : 5, 10, 12.5, 20, or 25 Hz
Output rate ii : 10, 25 or 50 Hz
Operating temperature: − 30° to 50°C
ii user selectable
7