The LI-7200RS Enclosed CO2/H2O Gas Analyzer is designed for high-speed CO2 and water vapor gas exchange measurements. It combines the performance of a closed path analyzer with the ruggedness and low power demands of an open path instrument. Minimizes data gaps with continuous measurements through rain, snow, and fog. Improved optics and temperature controls increase long-term stability and reduce drift—even when the instrument is not cleaned for weeks at a time. Logs complete eddy covariance data sets—including wind speed measurements from a sonic anemometer and supporting meteorological, radiation, and soil data from a LI-COR Biomet System.

The LI-7200RS uses non-dispersive infrared spectroscopy to measure CO2 and water vapor densities in air. It transmits infrared radiation through temperature-controlled optical filters, then through the closed sample path to a thermally regulated lead selenide detector. Some of the infrared radiation is absorbed by CO2 and water vapor in the sample path. Gas densities are computed from the ratio of absorbed radiation to a reference.

Using a patented configuration, the analyzer also measures temperature and pressure of the sampled air at high speeds—synchronously with the gas measurements. These data are combined to compute wet and dry mole fractions at speeds up to 20 measurements per second.