An Eddy Covariance System is designed to measure fluxes in the surrounding air, such as momentum flux, latent heat flux and sensible heat flux. It consists of an Ultrasonic Anemometer, DataPacker or DataLogger to combine various analog and digital outputs with the Ultrasonic Anemometer, and Flux Measurement Software package (FluxSoft). The basic system will provide momentum and sensible heat fluxes, and by adding a hygrometer, H2O and latent heat fluxes can also be made available.
The Flux Measurement System (FluxSoft) Software is a Linux-based software package designed to accomplish data collection, storage and processing. The FluxSoft Software comes installed on a computer or laptop that you specify at time of ordering.
The FMS receives sampled raw data from the attached instruments. The data are then processed and the raw data, as well as the processed data, can be sent out a variety of different communications links, or stored on the data storage device installed in the system.
The FMS system uses a the ATI DataLogger for the timesensitive tasks of instrument triggering, data collection, and initial data storage, and then a Linux-based personal computer for system control, longer-term storage, data analysis, and data visualization.
The system may be configured with an unreliable or parttime data link between the DataLogger and the supervisory personal computer, and the FMS system will provide for data integrity.
The following instruments can currently be supported by the FMS Software:
- ATI Sonic Anemometer/Thermometer
- ATI Data Packer
- ATI Data Logger
- ATI Cluster Controller
- Analytical Applications Infrared Hygrometer
- Analytical Applications Infrared Analyzer
- LICOR #6262 Hygrometer
- LICOR #LI-7500 Analyzer
- Analog Inputs
When a Sonic Anemometer is connected to the FMS, the following parameters can be measured:
- Vector Averaged Wind Speed
- Vector Averaged Wind Direction
- Standard Deviation
- Momentum Flux
- Friction Velocity
- Sensible Heat Flux
By adding a fast response hygrometer, and/or analyzer, along with a temperature sensor and pressure sensor, the following parameters can also be measured:
- Latent Heat Flux
- Mixing Ratio
- Vapor Pressure
- Air Density
- Specific Heat at Constant Pressure
- Heat of Vaporization
- H2O Flux
- Flux of measured component (i.e. CO2, etc.)
The data are stored on either a fixed hard drive, or other data storage device installed in the system. Both raw data and processed data can be stored. The data are stored as ASCII text.
ATI can provide custom data formats should the need arise.
The basic hardware requirements are as follows:
- IMB compatible PC, @1.0GHz
- 256 meg RAM
The system will support the following hardware:
- A/D boards from most manufacturers
- D/A boards from most manufacturers.
- Serial I/O boards from Comtrol
- Hard and floppy drives