The GHG Sentinel™ is a continuous automated greenhouse gas monitoring system. This field deployable device performs time-series measurement of Carbon Dioxide (CO2), Methane (CH4) and Oxygen (O2) in freshwater environments without taking water samples to the laboratory for costly analysis. The GHG Sentinel™ can be deployed on a floating platform in a reservoir, within the powerhouse of a hydroelectric facility and also as a shore station in the tail race. The system is designed with multiple air and water flow sensors and the powerful WatchMan500™ controller, so the system can run for months without servicing. The GHG Sentinel™ can also be controlled remotely for real-time data display as well as station management and system diagnostics.
The GHG Sentinel™ product is based on the research and prototype developed by the Department of Fisheries and Oceans Canada. Since then continuous monitoring systems have been installed in hydro generating stations in the provinces of Manitoba and Québec. AXYS has refined the core system design and utilized its years of remote environmental monitoring experience and expertise to optimize the unit for longer term field deployments. The most significant improvements include remote system management with greater control of flow rates as well as the flexibility to add new sensors to the system with the already available spare sensor ports.
GHG Sentinel™ Controller Processor
The AXYS proprietary WatchMan500™ is the core technology for the GHG Sentinel™. The WatchMan500™ controls and operates the complete system and provides the interface to the sensors and telemetry (for remote operation), system health monitoring, data logging, and data acquisition. Processing algorithms to calculate GHG flux are handled by the GHG Sentinel™.
GHG Sentinel™ Software
The GHG Sentinel™ Data Management System (DMS) software suite facilitates complete control over the GHG Sentinel™. Features include intuitive remote configuration, diagnostics and archiving of the data acquired by the GHG Sentinel™ into a SQL database and/or ASCII text files. The AXYS DMS includes SmartWeb™ functionality which is an intuitive data presentation tool to allow users the ability to easily generate tables, graphs and regular reports with their GHG Sentinel™ data. Data can also easily be exported to a variety of formats.
GHG Sentinel™ Telemetry
Multiple telemetry options are available including VHF radio, Inmarsat D+, Iridium, GSM and CDMA cellular phone. The data from the GHG Sentinel™ can include the time-series measurements of GHG concentrations from freshwater, system health status data, system configuration information and threshold alarm messages. Data from additional optional sensors can also be transmitted. All data is stored on the internal data logger and can be downloaded onto a computer directly on site or remotely.
Product Documentation
GHG Sentinel (PDF, 1.5MB)
Sensor Specifications
| Standard |
Range |
Resolution |
Accuracy |
| Carbon Dioxide CO2 |
0-20000ppm |
1ppm |
< 2.5% w/ 14cm bench |
| Methane CH4 |
0-1000ppm |
1ppm |
+/-5ppm |
| Oxygen O2 |
0-100%, 0-75mV |
0.01mV |
+/-0.35mV |
| Water Temp |
-30°C to +50°C |
0.01°C |
+/-0.15°C |
AXYS exclusively uses the LI-COR LI-820 CO2 Analyzer as a component in every GHG Sentinel. It is an absolute, non-dispersive infrared (NDIR) gas analyzer based upon a field proven single path, dual wavelength, and thermostatically controlled infrared detection system. The LI-820 closed path CO2 was also chosen due to its low power and maintenance requirements, as well as its suitability to a wide range of demanding environmental conditions. For more information on LI-COR and the LI-820, visit www.licor.com.