LI-7500
Open Path CO2/H2O Gas Analyzer
A Novel Design In an Analyzer for Eddy
Covariance Studies
The smooth, simple, aerodynamic profile of the LI-7500
Open Path CO2/H2O Gas Analyzer belies the innovations within - optics,
electronics, and software - that allow fast, precise measurements of in situ
densities of CO2 and H2O in turbulent air structures. In eddy covariance studies,
these data are used in conjunction with sonic anemometer turbulence data
to determine the fluxes of CO2 and H2O. Applications include determining
the carbon dioxide and water vapor budgets of agricultural or natural landscapes
such as forest canopies, grasslands, deserts, oceans, etc. for global change
and ecological studies.

The novel open path design provides a number of benefits over other flux
measurement systems, including:
- High speed and precision.
- Low power consumption, so that in remote environments the LI-7500 can
be powered by batteries or solar panels.
- Absence of internal or external tubing allows for undamped measurements
of CO2 and water vapor fluctuations, and no time delays
- A sealed sensor head with sapphire optical windows allows operation
in harsh environments at temperatures ranging from -25 to 50 °C (-40 to
50 °C is also possible - consult LI-COR). In addition, the
lightweight LI-7500 sensor head can be mounted in virtually any desired
orientation.
- A weatherproof box houses the control unit's high speed Digital Signal
Processing (DSP) electronics. Serial data are output at selectable
speeds of up to 20 Hz, and linearized, user-configurable Digital-to-Analog
Converters (DACs) output analog signals, which are updated at 300 Hz.
- A simple Windows® interface software provides for easy setup, calibration,
and monitoring. In addition, the software provides:
- Real-time graphical data output.
- On-board diagnostics to alert the user to potential problems that can
compromise data.
- User-programmable Delay Time feature to synchronize CO2 and
H2O data with
data from sonic anemometers.
Why should you consider the LI-7500 Open Path CO2/H2O
Gas Analyzer? (learn more...)
Photo courtesy of Campbell Scientific.