19-10-2017
Eddy covariance (EC) is a popular technique to measure and calculate CO2/H2O and other trace-gas fluxes in the atmospheric boundary layer. A typical workflow of a large network involves setting up and maintaining instruments, collecting high-frequency data, post-processing that data, and finally publishing data. The EasyFlux™ software suite streamlines this process. The interaction of the suite's products and their descriptions are below.
Introduced in 2015, EasyFlux DL was the first EasyFlux product offered by Campbell Scientific. Five EasyFlux DL variations support different eddy-covariance system configurations. These open-source CRBasic datalogger programs are distributed free of charge (www.campbellsci.eu/downloads). The programs measure EC sensors at 10 or 20 Hz; apply the appropriate data filtering (diagnostic flags, signal strength, and plausible measurement ranges); apply community-accepted corrections; determine the quality classifications; and analyze the flux footprint characteristics. The fluxes include: CO2, H2O, CH4, N2O, momentum fluxes, and energy balance. The exact output depends on the system configuration. Other online processing includes:
- Lag CO2/H2O against 3D wind to maximize the fluxes with additional constraints to ensure physically possible lags
- Coordinate rotations: double-rotation method or planar fit method
- Frequency response corrections using models and methods adopted by the community, and applicable to Campbell Scientific instruments
- SND correction to derive sensible heat flux from sonic sensible heat flux. Additionally, directly measured and corrected sensible heat flux is available for studies on energy balance.
- Shadow, spectroscopic, and WPL corrections; data quality classification; and flux source footprint
- Output of data in AmeriFlux format
Campbell Scientific will soon offer EasyFlux Web, a browser-based software for managing the network and collecting data from stations running EasyFlux DL. The software can be installed and hosted within a local network or it can be hosted by Campbell Scientific in the cloud. Browser-based, responsive design means the displays are readable on a large PC monitor or on a mobile device. EasyFlux Web is compatible with SQL-based databases, and allows the user to:
- Configure and display meta data for each EC station
- Monitor the status of the station including sensors, peripherals, and power
- View hourly time-series data
- Download data from specific periods in several different file formats
- Configure alarms (e.g., low power, low available card storage, instrument diagnostic flags)
EasyFlux PC post-processing software is now available. This intuitive user interface allows the user to easily configure the project and quickly begin processing high-frequency data collected by Campbell Scientific-based eddy-covariance systems. Features include:
- Simple to use graphical user interface (GUI)
- Logical top-to-bottom work flow
- Default settings specific for Campbell Scientific eddy-covariance systems
- Quick project setup and execution
- Software based on community-accepted and tested open-source code
Use in Eddy-Covariance Systems
When used in conjunction with the five Campbell Scientific eddy-covariance systems, the EasyFlux suite offers the FLUXNET community an easy, systematic approach to high-frequency data processing, data management, and network communication. Each of the five eddy-covariance systems has a unique EasyFlux DL program that is supported by EasyFlux PC and EasyFlux Web.