Open Path Eddy Covariance Training (OPEC)

The Open path Eddy Covariance Training (OPEC) class covers the proper use of Campbell Scientific equipment in eddy covariance measurements. This course does not cover micrometerology theory. Basic theory and assumptions used will be noted with respect to proper use and installation of eddy covariance systems. It is recommended that micrometerology related classes at a university or graduate level be completed prior to registration for this class. This course is not intended as a substitute for our CR1000 training course.

(Note: For a course that offers more training in eddy covariance theory consider the 3rd Annual Summer Course in Flux Measurements and Advanced Modeling.)

The training course is taught by Campbell Scientific Applications Engineers. Class size is limited to ensure personalized instruction and assistance. "Hands-on" programming exercises and course handouts are used to reinforce the concepts covered by the instructors.

Course fees include a Training Manual and the use of a datalogger, computer, and sensors. Lunch will be provided all course days, and there will be a tour of Campbell Scientific's facilities. A brief course outline is listed below:

1. Theoretical considerations

• Definition of flux and main assumptions of eddy covariance technique
• Sensible heat ( H ), latent heat ( LE ), and CO2 ( Fc ) flux definitions
• Definition of energy balance what are the main components, what is energy balance closure

2. System description and components

• Basic OPEC system sensors included
• Extended OPEC System additional sensors needed to close energy balance
• Additional fast response sensors

3. Installation of OPEC System

• Fetch and station position
• Measurement field size requirements
• Position of EC station and sensors
• CSAT3 mounting: orientation, leveling, cable connections
• LI-7500A IRGA mounting: control box, sensor head, fuse check
• Enclosure mounting
• Energy Balance sensors: net radiometer, soil heat flux plates, soil temperature probe, soil moisture probes
• Datalogger configuration and program downloading using a laptop

4. Introduction to programming with CRBasic

• CR1000 Hardware
• CR1000 Specifications
• CR1000 Memory
• Short Cut Program Generator
• LoggerNet
• Introduction to Programming with CRBasic
• CRBasic Editor
• Automated Data Collection
• File Control, Operating Systems and Transformer

5. OPEC Programming

• What is measured
• What is processed
• What is saved as data
• Output format with units for both, time-series and mean values
• User entered variables for OPEC if needed
• Measurement section
• Where to add auxiliary sensor measurements

6. SDM Connections

• Timing diagram of the 3 lines.
• CSAT3 - two scan delay at any sample rate.
• The LI-7500A IRGA - 300 mSec delay, three scans at 10 Hz and six scans at 20 Hz
• SDM lead length limitations data from CSAT3 and LI-7500A combined
• SDM-HUB reducing total SDM lead length
• SDM Datalogger instructions to slow SDM baud rate
• CRBasic SDM bit period search programs

7. CSAT3 Three Dimensional Sonic Anemometer

• Initial setup factory settings, SDM address
• Operational principles digital signal processing, ultrasonic signal
• CSAT3 trigger - CSAT3 SDM instruction and parameters in configuring the CSAT3
• CSAT3 diagnostics byte
• CSAT32 software
• Criteria used for discarding measurement from on-line processing
• Zero offset check

8. LI-7500A IRGA

• Initial setup - Campbell Scientific, Inc. factory default settings, SDM address, bandwidth, delay (297.7 mSec or ~ 300 mSec).
• Theory of operation: measuring absorptance, relating absorptance to concentration, cross-sensitivity, zero drift, basic equations
• LI-7500A SDM instruction and parameters in configuring the LI-7500A IRGA
• LI-7500A Software
• LI-7500A IRGA diagnostic byte
• Criteria used for discarding measurement from online processing
• Zero and span LI-7500A IRGA

9. Site Maintenance

• CSAT3
  • Check the status and position of the wicks
  • Check the surface conditions of the transducers, and clean them, if necessary 
  • Check the junction and clean it, if using FW05
• LI-7500A IRGA
  • Check the condition of the sapphire window, and clean, if necessary
  • Zero and Span
• Enclosure
  • Check the condition inside the enclosure for condensation, and replace the desiccant bags, if necessary

10. Data Retrieval and Management

• Direct connection and data retrieval via Loggernet
• Remote data retrieval via PC or Compact Flash Card
• Discussion on Industrial Grade SLC CF cards vs. Commercial MLC CF cards

11. Data Processing

• File management with CardConvert format options, converting CSI formats
• Brief discussion on CSI File Formats: TOB1, TOB3, TOACI1, TOA5
• Online Processing
• Off-line Processing with EdiRe
  • Processing List
  • Basic Data Processing
  • Location Output Files
  • Extract
  • User Defined Fast
  • Raw Subset (filtering based on CSAT3 and LI-7500A diagnostic flags)
  • 1 chn statistics (covariance)
  • 2 chn statistics (standard deviation and mean)
  • Wind speed and direction (CSAT3 and compass coordinates)
  • Webb correction
  • Plot Value
  • NaN and INF test
  • Advanced Processing