Methane (CH₄) Tracer Study

Source code and documentation for methane tracer release plume dispersion study. There are two main components:

• A stationary release site with
  • 3D ultrasonic anemometer (CSAT3B; Campbell Scientific)
  • Regulated point-release of CH₄:
    • 99.0% (commercial purity) methane (Matheson Tri-Gas)
    • high-purity, dual-stage regulator with flash arrestor
    • 5 SLPM mass flow controller (Alicat Scientific) with flash arrestor
• And a mobile station with:
  • Methane (CH₄)/carbon dioxide (CO₂) analyzer (UGGA; Los Gatos Research
  • GPS receiver (GPS16X-HVS; Garmin)
  • Programmable datalogger (CR6; Campbell Scientific)

The mobile station can be located up to 40m (130ft) from the stationary release site. Position data is logged in real-time to relieve the operator of tracking sampling location.

An Android tablet computer is used to interact with system components. Both the logger and gas analyzer have dedicated wireless networks for administration via appropriate apps:

• For the datalogger, LoggerLink provides complete control and data monitoring capabilities
• For the CH₄ analyzer, VNC Viewer allows the tablet to substitute for monitor/keyboard/mouse hardware

Operating Procedures

See here.

Diagrams

Experimental Hardware

Methane Release Hardware

Logger Enclosure Diagram

Analyzer Setup Diagram

Data stuff

Raw measurements are stored at 10Hz and, where appropriate, aggregated to 1-min values. Data is retained to microSD card memory; there is no telemetry component.

Two data tables files are generated each time the datalogger is started or after 12 hours of runtime. Runs are distinguished by a numeric filename suffix.

• ch4plume-tsdata: raw time-series data recorded at 10Hz
• ch4plume-stats: one-minute aggregations of select values; more for quality control

Field names (columns) contain a prefix indicating the data source. Refer to comments for a brief description, or the relevant instrument manual for more details on a particular field.

• csat3b: sonic anemometer
• ugga: methane analyzer
• gps: GPS receiver
• logger: data logger

References

• Alicat Scientific. MC/MCD Mass Flow Controller Manual. Rev 42, 2017 May 22. Online: https://www.alicat.com/documents/manuals/Gas_Flow_Controller_Manual.pdf

• Campbell Scientific, Inc. CR6 Measurement and Control System Operator's Manual. Revision 2018 Dec 19. Online: https://s.campbellsci.com/documents/us/manuals/cr6.pdf

• Campbell Scientific, Inc. CRBasic Program Reference: WindVector. Version CR1000.Std.32. CRBasic Editor.

• Campbell Scientific, Inc. CSAT3B Three-Dimensional Sonic Anemometer. Revision 2018 Mar. Online: https://s.campbellsci.com/documents/us/manuals/csat3b.pdf

• Campbell Scientific, Inc. GPS16X-HVS GPS Receiver Instruction Manual. Revision 2017 Oct. Online: https://s.campbellsci.com/documents/us/manuals/gps16x-hvs.pdf

• Los Gatos Research. Ultra-Portable Greenhouse Gas Analyzer (UGGA) User Manual Model 915-0011. Revision 2016 Jul 22.

  By manufacturer request only - see hardcopy or Lab Manager for pdf.