Sensors at all four flux towers make continuous measurements of CO2 and water content in the air as well as wind speed and direction—the core measurements required to calculate CO2 and water fluxes over the land surface. They are measured at 10 times per second (10Hz) and logged in 30-minute time intervals. Additional sensors collect ambient air temperature and humidity, rainfall, soil temperature and moisture, downwelling and upwelling radiation, and photosynthetically active radiation—also logged in 30-minute time intervals. The Thompson Farm (forest) and West Edge (impervious surface) sites are powered with in-line AC power; the Moore Fields (corn) and Kingman Farm (hay) sites are powered by a solar array (two 235W Canadian Solar Inc. CS6P-235PX panels at each site) installed as a dedicated continuous power source for these flux tower sensors.
Currently, all raw data are recorded on a data logger at each flux tower via a USB flash drive and retrieved from the field weekly. CO2 and water concentrations are processed with wind speed and direction in-house at the UNH-Durham campus to calculate CO2 and water fluxes over each site using the Eddy Pro® software.