The AmeriFlux Portable Eddy Covariance System (PECS) is used to evaluate data quality at sites in the AmeriFlux network. The PECS is deployed side-by-side for short deployments (10-14 days). The current PECS was designed and built by Dave Billesbach. The Tech Team has two PECS which allows simultaneous deployments. The PECS may be operated in different configurations depending on the site, power availability, and available infrastructure. In addition to the eddy covariance sensors, the PECS includes a suite of meteorological and radiation sensors (see table). No below-ground sensors are included currently. Data acquisition is handled using an on-board computer and a datalogger. Remote access to the PECS is possible via a cellular modem. The system may include a portable gasoline generator, or solar system to provide power depending on the site.
Photo of AmeriFlux Portable Eddy Covariance System (PECS)
Table of Portable Eddy Covariance System (PECS) components
| Gas Analyzer | LI-COR | LI-7500A (open-path)
LI-7700 (open-path)
LI-7200 (closed-path) |
CO2, H2O mole densities
CH4 mole density and mixing ratios
CO2, H2O mole densities and mixing ratios |
| 3D Sonic anemometer | Gill
ATI |
R3-50
“K” style |
u, v, w, Ts
u, v, w, Ts |
| Radiation sensors | Kipp & Zonen
Kipp & Zonen
Delta-T |
CNR4
PQS1
SPN1 |
4-component net radiometer (SWin, SWout, LWin, LWout, Tbody)
Photosynthetically Active Radiation (PARin, PARout) Total and diffuse radiation |
| Temperature/Relative humidity | RM Young
Vaisala |
41342
HMP155 |
Tair (aspirated)
Tair/RH |
| Barometric pressure | Vaisala | PTB110 | Patm |
One thing that Stephen has forgotten to mention is that he also has made a number of important and very useful modifications to the original design. I might also mention that the eddy covariance program we use for data collection is now available to the community. It’s called HuskerFlux and will run on any Windows computer (desktop, laptop, Single Board Computer). HuskerFlux directly ingests serial data streams (RS-232) from all of your instruments and synchronizes the streams into a single binary data file that can then be fed to your favorite post-processing code (there is also a companion post-processing system that you might also want to consider). Drop us a line if you’re interested.