HOP Helicopter Observation Platform @ Duke University

The Forest-Atmosphere Carbon Transfer and Storage (FACTS-I) facility is located in the Blackwood Division of the Duke Forest. It consists of four free-air CO₂ enrichment (FACE) plots that provide elevated atmospheric CO₂ concentration and four plots that provide ambient CO₂ control. The system has been in operation since June, 1994 in the prototype plot, and since August, 1996 in the three additional plots. The prototype plot and its reference were halved with a barrier inserted in the soil in 1998 to conduct, together with five additional plot pairs, CO₂ versus soil nutrient enrichment experiments. The rest of the plots were partitioned in early 2005 and incorporated into the CO₂ versus nutrient experiment. To increase statistical power, four additional ambient plots were established in January, 2005, halved, and one half of each fertilized. Core funding for the Duke Forest FACE Facility has been provided by the Office of Science (BER), U.S. Department of Energy. For more information, visit the Duke FACE Project website.

The HOP research at the FACE site is part of a project funded by the Duke University Center for Global Change, which consists of exploring the "hot spots" of absorption of CO₂ in heterogeneous landscapes and their relations to the local (microscale) heat and energy balances. The HOP collected 35 hours of data in July 2006, flying a triangular pattern 10 km on the side at three altitudes in the convective boundary layer (CBL): (1) near tree top, (2) just below the top of the CBL, and (3) in the middle of the CBL.