Updated: 2011-07-11

Portable Flux Observation System

System outline

We have developed a portable flux observation system with a view to provide an on-site reference for quality control of observed flux data and to standardize the measurement systems especially for new observation sites. The system adopts the eddy correlation method to measure fluxes of sensible heat, water vapor and carbon dioxide; and it consists of an ultrasonic anemometer-thermometer (CSAT3/ Campbell), a closed-path infrared gas analyzer (IRGA, LI-7000/ LI-COR), a thermo-hygrometer (HMP45A/ Vaisala), a high-speed sampling data logger (CR-3000/ Campbell), and an air intake switch for calibration. All devices are generally powered by 12 or 24V DC converted from 100 to 240V AC input. All components are mounted in a plastic container to improve portability and installation convenience.

Left: Power supply unit, Right: Main unit

Main unit

EquipmentsModel, ManufacturerSupply Voltage
Consumption Current
Infrared gas analyzerLI-7000, LI-COR (USA)10.5 to 16VDC
4A max.
Ultrasonic anemometer-thermometerCSAT3, Campbell (USA)10 to 16VDC
Thermo-hygrometerHMP45A, Vaisala (Finland)7 to 35VDC
4A max.
BarometerPTB-100A, Vaisala (Finland)10 to 30VDC
4mA max.
Data loggerCR-3000, Campbell (USA)10 to 16VDC
Draft fan for thermo-hygrometerCF825D-12M, NIPPON BLOWER (Japan)12VDC
Air pumpMVP03V12BA1, PANASONIC (Japan)8 to 15VDC
Mass flow controllerCMQ0020, YAMATAKE (Japan)15 to 24VDC
300mA max.
Solenoid valveAG31-02-2-03A, CKD (Japan)
2 valves are mounted
900mA each
Flow meterRK1650, KOFLOC (Japan)-
Filter9922-05, BLASTON (USA)-

Power unit

EquipmentsModel, ManufacturerInput and Output
Switching Power SupplyPAA150F-12A, COSEL (Japan)Input: 100 to 240VAC
Output: 12V13A(max.)
Switching Power SupplyHWA050-24, SANKEN (Japan)Input: 100 to 240VAC
Output: 24V2.1A(max.)
Conceptual diagram of the portable system

Observations Using Portable System

The portable system was installed in some observation sites to compare with the routine system to determine the relative difference among sites.

Previous observations

Portable flux observation system user manual

2nd-chuukiseika26.pdf (889KB)

Click here for a sample of CR3000 control program. This sample program is in the public domain.

You can use it freely at your own responsibility. On no event will we be liable to you for any damages arising out of the use or inability to use the sample program.


OHTANI Yoshikazu, MIZOGUCHI Yasuko, TAKANASHI Satoru, YASUDA Yukio, IWATA Hiroki, NAKAI Yuichiro, YUTA Satoko, YAMANOI Katsumi (2010): Development of a portable CO2 flux observation system using a closed-path gas analyzer for intercomparison. Bulletin of the Forestry and Forest Products Research Institute, 9(1):31-36.

Related projects

- Special Coordination Funds for Promoting Science and Technology (Ministry of Education, Culture, Sports, Science and Technology) "Standardization and systematization of carbon-budget observation in Asian terrestrial ecosystem based on AsiaFlux network"

- Global Environment Research Account for National Institute (Ministry of the Environment) "Long-term Monitoring of Carbon Flux and Promotion of a Data Network in Asian Terrestrial Ecosystems"