Eddy Covariance Systems

For measurements of gas exchange between ecosystems and the atmosphere, LI-COR eddy covariance solutions combine precision instruments, on-site flux computation, and powerful post-processing software into a single package to deliver ecosystem insights faster than ever before.

Taking you from raw data to publishable results, fully integrated LI-COR systems streamline the research process, empowering researchers of all experience levels.

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Reliable data collection

Highly precise, low-power, and flexible instrument platforms chosen as standard by global flux networks

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Automated flux computation

Fully processed and corrected fluxes on site in real time with EddyPro® Software and the SmartFlux® System

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Reproducible post-processing

Tovi Software for data QC, gap filling, footprint modeling, and flux partitioning

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Instrumentation for data collection

With a complete LI-COR eddy covariance system, observations accurately reflect genuine differences in ecosystem-level gas exchange properties. Your results can be reliably interpreted, and you can submit manuscripts that are free of introduced bias from other non-standard instruments or processing methods.

Global standard for eddy covariance research

LI-COR systems include rapid and precise gas analyzer technology chosen as the global standard by major flux networks—including AmeriFlux, AsiaFlux, ChinaFLUX, Chinese Ecosystem Research Network (CERN), Cold and Arid Regions Network (CARN), Integrated Carbon Observatory System (ICOS), and National Ecological Observatory Network (NEON).

globe of major networks

Analyzers and instrument platforms

High-speed LI-COR gas analyzers have the lowest power requirements of any comparable analyzer. They accommodate a variety of sonic anemometers and mounting structures for proven performance and consistently reliable gas exchange data.

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Get the most accurate measurements

Is your instrument influencing your measurements? Fluxes are computed by partitioning the total air flow that is measured by the anemometer into three wind components. If the original air flow is distorted near the anemometer, various flow distortion errors can occur. Since there is no correction algorithm for flow distortion, it is critical to choose a gas analyzer and anemometer system that minimizes or eliminates this issue.

Air flow distortion by the anemometer is readily observed in wind speed measurements, where the bulk of a relatively small anemometer transducer can affect the wind being measured1, 2, 3, 4, 5, 6. Exact colocation of the analyzer within the anemometer is not a practical solution, since analyzer structure can disrupt the air flow past the anemometer transducers. Disruptions to turbulent flow from large objects near the sample volume are difficult to detect—and impossible to correct—without data from a second anemometer on the same tower6, 7, 8, 9. To date, there are no published equations to correct for this issue.

To facilitate the optimal analyzer position, LI-COR instrument platforms use a standard mounting solution that positions the gas analyzer at an appropriate distance from the sonic anemometer(s). This mounting design makes it easy to and to orient the eddy covariance system toward the prevailing wind for an ideal omnidirectional setup. This mounting design makes it easy to determine separation distances and minimize or eliminate the flow distortion in the anemometer for most wind directions—creating a carefully executed nearly-omnidirectional setup.

sonic anemometer flow distortion
An object that is too close to the sonic anemometer—whether it is a tree branch, a tower support, or a gas analyzer—can cause flow distortion and lead to measurement errors.

Complete, flexible systems

LI-COR systems can be customized from a basic, single-analyzer setup to advanced systems that measure methane flux and biological and meteorological variables. They work cohesively with LI-COR soil gas flux systems and leaf-level measurement instrumentation.

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eddy covariance instrument tower graphic

LI-COR advantages

LI-COR eddy covariance systems allow for reliable data collection.

Key Feature The LI-COR Advantage
Omnidirectional Instrument Positioning The analyzer and sonic anemometer configuration of LI-COR instrument platforms allows for reliable data collection from nearly any wind direction.
Instruments Separated to Reduce Flow Distortion Sensor separation with all available LI-COR instrument models mitigates the distortion of air flow through the sonic anemometer that is found in co-located configurations.
Temperature-Regulated Optical Components LI-COR analyzer optics are temperature regulated, mitigating signal drift with changing ambient temperatures.
Low Power Requirements The LI-7500DS draws only 4 W of power—the lowest of comparable analyzers—and is ideal for remote deployment.
Ability to Integrate Multiple Sonic Anemometer Models To meet individual research needs, LI-COR systems can be configured with more than 10 digital anemometer models from different manufacturers.
Streamlined Data Analysis Data from LI-COR instruments are optimized for processing using EddyPro Software and the SmartFlux System and for postprocessing using Tovi Software.
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Automated flux computation

EddyPro Software and the SmartFlux System deliver highly accurate, fully processed flux data in real time; they provide new standardized processing steps and adhere to formatting requirements from FLUXNET, ICOS, CERN, AmeriFlux, OzFlux, and other networks.

EddyPro Software

Get real-time insights into your data with fully processed fluxes on demand.

Along with LI-COR instruments, EddyPro has been widely adopted by researchers and networks around the world—including ICOS, CERN, Ameriflux, and many others.

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EddyPro software screenshot

EddyPro Advantage

With over 1500 peer-reviewed publications and continuous improvements driven by community partnerships, EddyPro has redefined the standard for flux processing data.

  • Easy configuration and use with a simple graphical user interface
  • Complete set of processing options (e.g., frequency response correction, random error estimation, and quality flagging)
  • Standardized computation routines used by leading flux networks
  • Seamless processing of LI-COR .ghg files and support for other file types
  • Integrated online help, videos, and technical support
EddyPro software advantage screenshot

EddyPro results on site with the SmartFlux® System

SmartFlux is the on-site processing and GPS synchronization component of LI-COR eddy covariance systems: it acts to synchronize a system’s clock and mitigate any drift or misalignments. The SmartFlux System runs EddyPro code to provide fully processed flux results in real time using raw data from a LI-COR gas analyzer and a sonic anemometer. Flexible data transfer options like automatic file transfer to a network server or private repository accommodate an existing setup.

Always online with FluxSuite® Software

FluxSuite is a secure cloud-based platform that displays fluxes, biomet data, and status information from your site. View and download real-time final fluxes, processed by EddyPro Software on the SmartFlux System, using your smartphone, tablet, or computer.

Try FluxSuite for Free
Smartflux tower

Always online with FluxSuite® Software

FluxSuite is a secure cloud-based platform that displays fluxes, biomet data, and status information from your site. View and download real-time final fluxes, processed by EddyPro Software on the SmartFlux System, using your smartphone, tablet, or computer.

Try FluxSuite for Free

LI-COR advantages

LI-COR eddy covariance systems allow for reliable reliable data processing.

Key Feature The LI-COR Advantage
Field-Based Microprocessor The ARM Cortex 720 MHz processor in SmartFlux applies over 50 flux processing algorithms in real time.
Incorporation of Widely Published and Accepted Corrections and Calculations SmartFlux corrects and processes fluxes using the peer-reviewed calculations and algorithms from EddyPro, including corrections and spectral analysis.
Reproducibility between Desktop and Embedded Software EddyPro produces the exact same results on a PC or in the SmartFlux System, allowing for easy replication across devices and sites. Comparative logger-based systems use different codes for embedded and desktop software, making reproducibility difficult.
Site-Specific and User-Specified Processing With LI-COR systems, flux processing routines can be customized for individual sites. Comparative logger-based systems only compute minimal, approximated flux data and exclude numerous critical steps.
Microsecond Time Synchronization SmartFlux integrates and synchronizes biomet and high-speed digital wind and gas analyzer data, ensuring fluxes are not biased by random and systematic timing errors.
Point-and-Click User Experience EddyPro features a thoughtfully designed and implemented graphical user interface. Comparative logger-based systems require custom programming with proprietary language.
Data Outputs Designed to Meet Flux Network Standards EddyPro outputs are designed to meet the latest FLUXNET, ICOS, and AmeriFlux database standards without requiring additional post-processing.
Extensive Resources and an Experienced and Dedicated Support Team A variety of support resources are available for EddyPro and SmartFlux along with a team of support scientists always ready to assist.
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Reproducible post-processing

As the final step in the start-to-finish LI-COR solution, Tovi Software is a data analysis software package that post-processes eddy covariance flux data. From QA/QC control and flux gap filling to u* threshold detection and footprint modeling, Tovi helps evaluate data in a comprehensive, step-by-step procedure. Access results quicker, move onto new projects sooner, and get more done in a grant cycle with Tovi.

See Tovi in action
Tovi Software logo

Consistently perform expert-level analyses

Tovi integrates widely accepted and cited post-processing calculations and algorithms into a single software package. By standardizing and automating complex calculations, your analysis is performed correctly and consistently each time. You can even export comprehensive reports containing complete documentation of your analysis, results, and citations—providing transparency for reproducible results.

These features combined with Tovi’s sleek, graphical user interface enables new and seasoned lab members alike to work with advanced post-processing techniques.

Tovi software energy balance screenshot Tovi software footprint screenshot

LI-COR advantages

Process data quickly, consistently, and thoroughly with Tovi.

Key Feature The Tovi Advantage
Automated and Standardized Post-Processing Calculations Be confident that your analysis is performed correctly and consistently. Remove site and user bias from your results.
Complete, End-to-End Post-Processing No need for multiple software applications or complex statistical software packages: from data import to QC, gap filling, u* threshold detection, and partitioning, Tovi allows for a complete post-processing workflow.
Transparency and Reproducibility Analysis output contains complete process documentation, which provides transparency for reproducible results. Collaborators and reviewers can quickly and easily review and reproduce your results.
Automatic Citation Generation Citations are automatically generated for the tools you use in your analysis, and researchers can collaborate and implement their codes for users around the globe.
Extensibility The unique, integrated Python and R Programming Notebook extends the features of Tovi to advanced users, while the simpler graphical user interface remains straightforward for new students and new lab members.
Data Processing Confidence The calculations and algorithms used in Tovi are the same peer-reviewed, open source tools used by the eddy covariance community and flux networks worldwide.

Why Choose LI-COR

LI-COR offers the lowest-cost eddy covariance systems that provide the most accurate measurements and are deployable in challenging environments. Industry-leading technical support from eddy covariance scientists and on-site education opportunities create an entirely comprehensive solution.

Save money and use less energy

LI-COR eddy covariance analyzers have the lowest cost configuration and power requirements among similar instruments. Featuring simplified hardware, the newly-redesigned LI-7500DS Open Path CO2/H2O Analyzer requires only 4 watts of power during normal operation—lower than any other EC gas analyzer available, making the analyzer ideal for deployment in remote areas where power is limited.

researchers set up Eddy Covariance station in the snow

Photo Credit: Alfred-Wegener Institut/Lianna Nixon, University of Colorado Boulder (CC-BY 4.0)

Deploy anywhere

LI-COR non-dispersive infrared (NDIR) gas analyzers provide consistently stable gas concentration measurements over a full temperature range. The open path LI-7500DS and LI-7700 and enclosed path LI-7200RS analyzers are designed to be used in challenging outdoor environments, where they are subject to large temperature extremes. Key optical components are actively temperature regulated, and electronics are designed to be stable over a wide range of temperatures.

The typical performance of LI-COR gas analyzers over a range of temperatures and CO2 densities is shown below. Due to careful optical and electronic design, the performance of LI-COR analyzers is consistent with theoretical expectations. Full calibration details are also provided with every instrument.

Eddy Covariance Products

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References

  1. Wyngaard, J. C., 1981. The effects of probe-induced flow distortion on atmospheric turbulence measurements. Journal of Applied Meteorology, 20: 784-794.
  2. Wyngaard, J. C., 1988. Flow-distortion effects on scalar flux measurements in the surface layer: Implications for sensor design. In Hicks, B. B. (Eds) Topics in Micrometeorology. A Festschrift for Arch Dyer. Springer, Dordrecht.
  3. Frank, J. M., W. J. Massman, and B. E. Ewers, 2013. Underestimates of sensible heat flux due to vertical velocity measurement errors in non-orthogonal sonic anemometers. Agricultural and Forest Meteorology, 171-172: 72-81.
  4. Horst, T. W., S. R. Semmer, and G. Maclean, 2015. Correction of a non-orthogonal, three-component sonic anemometer for flow distortion by transducer shadowing. Boundary-Layer Meteorology, 155 (3): 371-395.
  5. Frank, J. M., W. J. Massman, E. Swiatek, H. A. Zimmerman, and B. E. Ewers, 2016. All sonic anemometers need to correct for transducer and structural shadowing in their velocity measurements. Journal of Atmospheric and Oceanic Technology, 33(1): 149-167.
  6. Huq, S., F. De Roo, T. Foken, M. Mauder, 2017. Evaluation of probe-induced flow distortion of Campbell CSAT3 sonic anemometers by numerical simulation. Boundary-Layer Meteorology, 165(1): 9-28.
  7. Horst, T. W., R. Vogt, and S. P. Oncley, 2016. Measurements of flow distortion within the IRGASON integrated sonic anemometer and CO2/H2O gas analyzer. Boundary-Layer Meteorology, 160(1): 1-15.
  8. Dyer, A. J., 1981. Flow distortion by supporting structures. Boundary-Layer Meteorology, 20(2): 243-251.
  9. Grare, L., L. Lenain, and W. K. Melville, 2016. The influence of wind direction on Campbell Scientific CSAT3 and Gill R3-50 sonic anemometer measurements. Journal of Atmospheric and Oceanic Technology, 33(11): 2477-2497.

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