AmeriFlux Site Visits - QA/QC and calibrations

The Tech Team conducts site visits across the AmeriFlux network to maintain data quality, ensure data inter-comparability, and share technical expertise. The Tech team brings a carefully calibrated portable eddy covariance system (PECS) to AmeriFlux sites, where a side-by-side comparison is conducted. PECS deployments typically last between 10-14 days. Site visits are normally scheduled during the growing season (April-September). The Tech team targets 8-10 site visits per year.

A list of all past site visits is now available. You can also view this information as a map.

Request an AmeriFlux Site Visit

The Tech Team welcomes invitations from AmeriFlux sites. To request a site visit, fill out this online form.

What to expect before, during, and after a site visit

Months prior to visit
1. Sites visits planned and selected during winter (Dec-Feb)
  1. Initial contact – gauge interest/availability, discuss possible date ranges;
  2. Follow-up – confirm dates;
  3. Send site visit questionnaire (including request for recent data).
2. Logistics planning
  PECS equipment cases
  1. Tech Team arranges lodging and transport options;
  2. All costs of visit are covered by the the AmeriFlux Management Project.
1-2 weeks prior to visit
1. For site staff:
  1. Ensure site access and normal site operations (data, power, communications, etc)
  2. Confirm access and login credentials to AmeriFlux webpage.
2. For Tech Team:
  1. Ship equipment (10-16 large cases, 500+ lbs)
  2. Contact staff and confirm arrival and site access dates/plans;
  3. Fall protection permit (if necessary);
  4. Check weather;
  5. Rent appropriate vehicle.
Upon arrival
Gas analyzer calibration
1. Meet site staff;
2. Pickup equipment, purchase supplies;
3. Calibrate gas analyzers:
  1. Will usually occur the day prior to setup;
  2. Prefer lab setting to conduct calibration, if available.
  3. Bench top and power outlet required.
Setup day
1. Meet site staff at site;
  Site orientation
2. Discuss site safety and rules;
3. Site orientation;
4. Discuss AmeriFlux setup plans:
  1. Minimize interfering with site operations/instrumentation;
  2. Find optimal location for PECS instruments;
5. Tech Team can usually complete installation in a single day;
6. After setup complete, Tech Team will document and photograph.
During visit
1. Tech Team remain local for duration of visit:
  1. Monitor PECS and ensure data continuity;
  2. May collect ancillary measurements to report to Network;
  3. Assist with BADM and variable information entry;
  4. Available for consulting with site staff.
2. Mid-visit comparison
  CA-Mer site visit
  1. Preliminary data comparison between systems will be conducted and shared with site staff;
  2. Valuable opportunity to identify issues and resolve prior to end of comparison.
Take down day
1. Tech Team may request site staff assistance;
2. Post-visit calibration of gas analyzers will be conducted;
3. Tech Team will arrange transportation and shipment of equipment (but assistance always appreciated).
Post visit – data sharing
1. Files should include headers, units, metadata;
2. Description of processing steps, algorithms, and corrections applied. Don’t assume we know.
3. Do not gap fill data.
4. 30 minute processed data:
  1. Fluxes, covariances, correction terms;
  2. Statistics (mean, variance) for high frequency variables;
  3. Meteorological, radiation, ancillary data.
5. High frequency data:
  Wheelbarrow for PECS transport
  1. Tech Team will conduct independent data processing;
  2. Shared folder can be provided (i.e. Dropbox).
Tech Team report
1. Site visit reports shared with site staff (and no one else):
  1. Provide key recommendations;
  2. Extensive comparisons, analysis;
  3. Site benchmarked against cumulative record of site visits;
  4. Tech Team data available upon request from site;
  5. Feedback from site staff requested.