Published: 30 September 2010

Measurements of sensible, latent, and carbon dioxide fluxes are valuable for refining both regional and global climate models. Since 1997, only ARM’s Southern Great Plains site provided these continuous measurements using eddy correlation flux (ECOR) and energy balance Bowen ratio (EBBR) stations. Now, ARM’s tropical site in Darwin, Australia, is also providing these measurements, thanks to the American Recovery and Reinvestment Act. In August, three new ECORs were installed near the Darwin site, along with a complementary new instrument system, the SEBS (Surface Energy Balance System) in place of the EBBR. The new complementary ECOR/SEBS system includes a net radiometers and soil sensors for estimating the total surface energy balance.

The SEBS consists of a precision net radiometer for upwelling and downwelling measurements of solar and infrared radiation; a wetness sensor for dew, frost, rain, and snow; and surface probes for measuring soil moisture, heat flow, and temperature. The new system uses essentially the same equipment and data acquisition equipment as the SGP ECORs, but with a new data logger for the additional radiometer and soil sensors. Data will be collected in the ECOR computer and transmitted to the site data system via a cell phone modem. New infrastructure for mounts, signal towers, and electrical service was completed prior to the installations.

The ECOR/SEBS pairings will operate at locations with differing surface properties—ocean, grassland, and wetland. Acquired through the Recovery Act, the ECOR/SEBS instrument pairings will also be deployed at the ARM site in Barrow, Alaska, and with the second ARM Mobile Facility. The upgrades will be applied to the existing ECOR stations at the SGP site and with the AMF1, currently in the Azores.