IRGASON Integrated CO2 and H2O Open-Path Gas Analyzer and 3-D Sonic Anemometer
Powerful Research Tool
Combines two high-level sensors for eddy-covariance research
weather applications supported water applications supported energy applications supported gas flux and turbulence applications supported infrastructure applications supported soil applications supported

Overview

Campbell Scientific’s IRGASON fully integrates the open-path analyzer and sonic anemometer. Designed specifically for eddy-covariance flux measurements, the patented design is easier to install and use than separate sensors and provides increased measurement accuracy. The IRGASON simultaneously measures absolute carbon dioxide and water vapor, air temperature, barometric pressure, three-dimensional wind speed, and sonic air temperature. U.S. patent D680455

For more information about the benefits of having a co-located measurement, refer to the poster "Improved eddy flux measurements by open-path gas analyzer and sonic anemometer co-location."

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Benefits and Features

  • Combined support structure causes less flow distortion than two separate sensors
  • Truly co-located gas analyzer and sonic anemometer measurements avoid flux loss due to sensor separation
  • Synchronized gas analyzer and sonic anemometer measurements avoid the need to correct for time lag
  • Low power consumption; suitable for solar power applications
  • Measurements are temperature compensated without active heat control
  • Low noise
  • Maximum output rate of 60 Hz with 20 Hz bandwidth
  • Angled windows shed water and are tolerant to window contamination
  • Field rugged
  • Field serviceable
  • Factory calibrated over wide range of CO2, H2O, pressure, and temperature in all combinations encountered in practice
  • Extensive set of diagnostic parameters
  • Fully compatible with Campbell Scientific dataloggers; field setup, configuration, and field zero and span can be accomplished directly from the datalogger
  • Sonic temperature determined from three acoustic paths; corrected for crosswind effects
  • Innovative signal processing and transducer wicks considerably improve performance of the anemometer during precipitation events

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Technical Description

The IRGASON has the following outputs:

  • Ux (m/s)
  • Uy (m/s)
  • Uz (m/s)
  • Sonic Temperature (°C)
  • Sonic Diagnostic
  • CO2 Density (mg/m3)
  • H2O Density (g/m3)
  • Gas Analyzer Diagnostic
  • Ambient Temperature (°C)
  • Atmospheric Pressure (kPa)
  • CO2 Signal Strength
  • H2O Signal Strength
  • Source Temperature (°C)

Specifications

Patent U.S. Patent No. D680455
Operating Temperature Range -30° to +50°C
Calibrated Pressure Range 70 to 106 kPa
Input Voltage Range 10 to 16 Vdc
Power 5 W (steady state and power up) at 25°C
Measurement Rate 60 Hz
Output Bandwidth 5, 10, 12.5, or 20 Hz (user-programmable)
Output Options SDM, RS-485, USB, analog (CO2 and H2O only)
Auxiliary Inputs Air temperature and pressure
Warranty 3 years or 17,500 hours of operation (whichever comes first)
Cable Length 3 m (10 ft) from IRGASON® to EC100
Weight
  • 3.2 kg (7.1 lb) for EC100 electronics
  • 2.8 kg (6.1 lb) for IRGASON® head and cables

Gas Analyzer

Path Length 15.37 cm (6.05 in.)
A temperature of 20°C and pressure of 101.325 kPa was used to convert mass density to concentration.

Gas Analyzer - CO2 Performance

-NOTE- A temperature of 20°C and pressure of 101.325 kPa was used to convert mass density to concentration.
Accuracy
  • Assumes the following: the gas analyzer was properly zero and spanned using the appropriate standards; CO2 span concentration was 400 ppm; H2O span dewpoint was at 12°C (16.7 ppt); zero/span temperature was 25°C; zero/span pressure was 84 kPa; subsequent measurements made at or near the span concentration; temperature is not more than ±6°C from the zero/span temperature; and ambient temperature is within the gas analyzer operating temperature range.
  • 1% (standard deviation of calibration residuals)
Precision RMS (maximum) 0.2 mg/m3 (0.15 μmol/mol)

Nominal conditions for precision verification test: 25°C, 86 kPa, 400 μmol/mol CO2, 12°C dewpoint, and 20 Hz bandwidth.
Calibrated Range 0 to 1,000 μmol/mol (0 to 3,000 μmol/mol available upon request.)
Zero Drift with Temperature (maximum) ±0.55 mg/m3/°C (±0.3 μmol/mol/°C)
Gain Drift with Temperature (maximum) ±0.1% of reading/°C
Cross Sensitivity (maximum) ±1.1 x 10-4 mol CO2/mol H2O

Gas Analyzer - H2O Performance

-NOTE- A temperature of 20°C and pressure of 101.325 kPa was used to convert mass density to concentration.
Accuracy
  • Assumes the following: the gas analyzer was properly zero and spanned using the appropriate standards; CO2 span concentration was 400 ppm; H2O span dewpoint was at 12°C (16.7 ppt); zero/span temperature was 25°C; zero/span pressure was 84 kPa; subsequent measurements made at or near the span concentration; temperature is not more than ±6°C from the zero/span temperature; and ambient temperature is within the gas analyzer operating temperature range.
  • 2% (standard deviation of calibration residuals)
Precision RMS (maximum) 0.004 g/m3 (0.006 mmol/mol)

Nominal conditions for precision verification test: 25°C, 86 kPa, 400 μmol/mol CO2, 12°C dewpoint, and 20 Hz bandwidth.
Calibrated Range 0 to 72 mmol/mol (38°C dewpoint)
Zero Drift with Temperature (maximum) ±0.037 g/m3/°C (±0.05 mmol/mol/°C)
Gain Drift with Temperature (maximum) ±0.3% of reading/°C
Cross Sensitivity (maximum) ±0.1 mol H2O/mol CO2

Sonic Anemometer - Accuracy

-NOTE- The accuracy specification for the sonic anemometer is for wind speeds < 30 m s-1 and wind angles between ±170°.
Offset Error
  • < ±8.0 cm s-1 (for ux, uy)
  • < ±4.0 cm s-1 (for uz)
  • ±0.7° while horizontal wind at 1 m s-1 (for wind direction)
Gain Error
  • < ±2% of reading (for wind vector within ±5° of horizontal)
  • < ±3% of reading (for wind vector within ±10° of horizontal)
  • < ±6% of reading (for wind vector within ±20° of horizontal)
Measurement Precision RMS
  • 1 mm s-1 (for ux, uy)
  • 0.5 mm s-1 (for uz)
  • 0.025°C (for sonic temperature)
  • 0.6° (for wind direction)
Speed of Sound Determined from 3 acoustic paths (corrected for crosswind effects)
Rain Innovative signal processing and transducer wicks considerably improve performance of the anemometer during precipitation events.

Basic Barometer (option -BB)

Total Accuracy
  • ±3.7 kPa at -30°C, falling linearly to ±1.5 kPa at 0°C (-30° to 0°C)
  • ±1.5 kPa (0° to 50°C)
Measurement Rate 10 Hz

Enhanced Barometer (option -EB)

Manufacturer Vaisala PTB110
Total Accuracy ±0.15 kPa (-30° to +50°C)
Measurement Rate 1 Hz

Ambient Temperature

Manufacturer BetaTherm 100K6A1IA
Total Accuracy ±0.15°C (-30° to +50°C)
EC100 ingress protection IP65

Compatibility

Please note: The following shows notable compatibility information. It is not a comprehensive list of all compatible products.

Dataloggers

Product Compatible Note
CR1000
CR200X (retired)
CR216X (retired)
CR300
CR3000
CR5000 (retired)
CR6
CR800
CR850
CR9000X

Downloads

EasyFlux DL for CR6OP v.1.04 (77.8 KB) 05-08-2019

CR6 datalogger program for Campbell open-path eddy-covariance systems.

View Revision History

EC100 OS v.8.01 (561 KB) 07-05-2018

EC100 Operating System.

Watch the Video Tutorial: Updating the EC100 Operating System.

View Revision History

ECMon v.1.6 (10.7 MB) 29-03-2016

EC100-Series Support Software.


Device Configuration Utility v.2.22 (42.3 MB) 12-09-2019

A software utility used to download operating systems and set up Campbell Scientific hardware. Also will update PakBus Graph and the Network Planner if they have been installed previously by another Campbell Scientific software package.

Supported Operating Systems:

Windows 10, 8.1, 8, and 7 (Both 32 and 64 bit)

View Revision History

FAQs for

Number of FAQs related to IRGASON: 21

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  1. The molecular sieve is a direct replacement for the old magnesium perchlorate bottles. The molecular sieve may be used for any Campbell Scientific analyzer that used the old bottles.

  2. The molecular sieve has been demonstrated here by our engineering department to be effective at removing CO2 and H2O from the air sample. The change was made for two reasons:

    1. It was a safer alternative than using the previous chemicals.
    2. Increased shipping regulations for the chemicals limited the number of suppliers. 
  3. The molecular sieve is a non-hazardous material that can be shipped to any country.

  4. The bottles of sieve for drop-in replacement contain the pellets and a membrane on top. The membrane is necessary to keep the pellets contained while allowing gas to pass over the zeolite. The bottle has the same footprint as the old magnesium perchlorate bottles. The amount in each bottle is listed on the bottle. The amount of sieve needed for each analyzer is the following:

    • The EC150 needs 22 g (drop-in bottle).
    • The IRGASON® needs 22 g (drop-in bottle).
    • The EC155 needs 22 g (drop-in bottle).
    • The AP200 needs 500 g (refill).
    • The 27423 needs 1000 g (refill).
    • The 31022 needs 500 g (refill).
  5. Yes. A fine-wire thermocouple, such as a FW05, can be used.

  6. The factory calibration accounts for CO2 and H2O signal strengths down to 0.7. Therefore, to ensure quality data, windows should be cleaned before signal strengths drop below 0.7. 

  7. The power requirement for the IRGASON® or EC150 with CSAT3A is 5 W at room temperature regardless of whether it is powering up or under steady-state operation.  At extreme cold or hot temperatures, the power requirement reaches 6 W.

  8. The barometer and temperature sensor are needed because the IRGASON® and EC150 have been calibrated at the factory over a range of temperatures (-30° to +50°C) and barometric pressures (70 to 106 kPa). 

  9. For greatest accuracy, Campbell Scientific recommends that a zero and a span be done on the EC150 or IRGASON®. However, if a span gas is difficult to obtain, at the minimum, perform a zero on the analyzer.  Performing a zero will correct the majority of drift experienced by the analyzer. Follow the zero procedure in the analyzer’s manual for details.

  10. The EC150 and IRGASON® can report a negative water concentration if enough liquid water accumulates on the optical windows. This is because the absorption spectrum of liquid water differs from that of water vapor. Typically, large rain droplets do not cause this phenomenon. Rather, misty or condensing conditions, which create a water film across the entire optical window, can cause this phenomenon. After the water film evaporates, the former measurement accuracy will be restored.  

    The IRGASON® and EC150 may also experience some amount of drift over time. If conditions are relatively dry and it has been a long time since a zero and span has been performed on the analyzer, it is possible to report a negative water vapor concentration. In this situation, perform a zero and span of the analyzer.