LI-7700
Open Path CH4Gas Analyzer
The LI-7700 Open Path CH4 Analyzer features an open sample path that measures methane density in ambient air.
The LI-7700 is designed specifically for eddy covariance flux measurements to evaluate methane emissions from the terrestrial landscape. It provides low-maintenance long-term operation in demanding field deployments. Low power consumption: Draws 8 watts of power nominally, making it ideal for use with solar power supplies in remote locations. High precision measurements: 5 ppb RMS noise at 10 Hz in typical ambient concentrations. Self-cleaning optics: Monitors signal strength and automatically cleans the lower mirror when the signal drops below a user-settable threshold. Heated mirrors reduce condensation on optics, which prevents data loss during humid conditions.
Innovative Solutions
Remote Field Deployment
- Low power (8 W during normal operation)
- Light weight (5.2 kg)
- Low maintenance
- Designed for long-term, unattended, continuous operation
Eddy Covariance
- High precision (5 ppb RMS noise @ 10 Hz, 2000 ppb CH4)
- High-speed data output (up to 40 Hz)
- Simplified data integration
- Analog inputs for sonic anemometer data
Open Path
- In-situ methane density measurement using laser spectroscopy
- Enables low power system operation
- No time delays or attenuation from tubing
- No pump required
Designed for Field Use
- Radiation shield minimizes condensation on the upper mirror
- Carbon fiber spars minimize thermal expansion of the optical path
- Heaters keep mirrors near ambient temperature to prevent condensation
Why the LI-7700?
- High precision and accuracy
- Low power
- Long-term, low maintenance operation
- Easily integrates into flux towers
- Simplified data integration
- Light weight
