LI-7500A Open Path CO2/H2O Analyzer
Used in over 90% of CO2 flux towers worldwide, some having been continually deployed for 10+ years.
The LI-7500A is a high speed, high precision, non-dispersive infrared gas analyzer that accurately measures densities of carbon dioxide and water vapor in situ. With the eddy covariance technique, these data are used in conjunction with sonic anemometer wind speed to determine to determine ecosystem level fluxes of CO2 and H2O.
The LI-7500A accepts analog data from a sonic anemometer and logs complete data sets to a removable USB storage device.
The LI-7500A makes high speed, high precision CO2 and H2O measurements over a wide range of concentrations.
- 0.11 μmol/mol CO2; 0.0047 mmol/mol H2O typical *
- CO2 measurements from 0-3000 ppm; H2O measurements from 0-60 mmol/mol
Optical sources and filters are temperature regulated to provide long term analyzer stability. High accuracy and precision are maintained under large diurnal temperature variations in the field.
The LI-7500A draws only 12 W of power (nominally), this makes it possible to use the analyzer in remote locations that don’t have access to main power.
The LI-7500A includes the LI-7550 Analyzer Interface Unit, which provides 4 analog input channels and 4 GB (16 GB optional) of removable (USB) memory. This configuration can log more than 4 months of eddy covariance data, as well as other variables, all in Greenhouse Gas Format (.ghg) for seamless processing with EddyPro™ software.
Ethernet connectivity allows for remote access to instruments from your office or lab. You can check status, download data, view real time data, and adjust instrument configurations without going to the site.
The
World-Wide Standard
LI-7500A images courtesy of National University of Singapore, Princeton University, National Institute for Agro-Environmental Sciences
The LI-7500/LI-7500A is the most widely used open-path CO2/H2O analyzer in the world. Since its introduction in 1999 it has been directly cited in over 1500 peer-reviewed scientific publications, and scientists rely on the analyzer for its high precision, accuracy, and stability. Many instruments fielded in 1999 are still in continual field use today.
Over 90% of CO2 flux towers worldwide use LI-COR gas analyzers, including the following major flux networks:
The LI-7500A is only part of a larger eddy covariance system from LI-COR. This solution includes a sonic anemometer, optional open-path methane analyzer, EddyPro™ eddy covariance flux processing software, additional meteorological sensors, scientific support, and technical support. LI-COR eddy covariance solutions provide scientists with field tested instrumentation, cutting edge flux processing software, and experienced scientific and technical support that are unmatched in the field.
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Upgrade to the LI-7500A
- On-board high speed data logging
- Lower power consumption setting in cold environments
- Data import directly into EddyPro for flux processing
Dec 14, 2011
Webinar:
The Eddy Covariance Method:
EddyPro 3.0 Data Processing Software with Advanced Settings
Watch NowLI-7500A Resources:
- Featured Publications:
- B.E. Law, O.J. Sun, J. Campbell, S. Vantuyl, and P.E. Thornton, 2003. Changes in carbon storage and fluxes in a chronosequence of ponderosa pine. Global Change Biology 9, 510-524.
- J.L. Lewicki, G.E. Hilley, L. Dobeck, B.D.V. Marino, 2011. Eddy covariance imaging of diffuse volcanic CO2 emissions at Mammoth Mountain, CA, USA. Bull Volcanol doi 10.1007/s00445-011-0503-y.
- S.D. Miller, C. Marandino, and E.S. Saltzman, 2010. Ship-based measurement of air-sea CO2 exchange by eddy covariance. Journal of Geophysical Research, Vol. 115, D02304, doi:10.1029/2009JD012193, 2010.
- Liukang Xu, Dennis D. Baldocchi, 2004. Seasonal variation in carbon dioxide exchange over a Mediterranean annual grassland in California. Agricultural and Forest Meteorology 1232: 79-96.
- Siyan Ma, Dennis D. Baldocchi, Stefania Mambelli, and Todd E. Dawson, 2010. Are temporal variations of leaf traits responsible for seasonal and inter-annual variability in ecosystem CO2 exchange? Functional Ecology, doi: 10.1111/j.1365-2435.2010.01779.x.
- Jessica L. Schedlbauer, Steven F. Oberbauer, Gregory Starr, and Kristine L. Jimenez, 2010. Seasonal differences in the CO2 exchange of a short-hydroperiod Florida Everglades marsh. Agricultural and Forest Meteorology 150: 994-1006.
