THE DUKE UNIVERSITY HELICOPTER OBSERVATION PLATFORM

To establish a helicopter observation platform (HOP), Duke University has purchased a Bell 206 "Jet Ranger" helicopter, which has been equipped with a three-dimensional, high-frequency positioning and attitude-recording system, a data acquisition and real-time visualization system, and high-frequency sensors to measure turbulence, temperature, moisture, and CO2 concentration. Thus, it can collect the variables needed to compute some of the turbulent heat and scalar fluxes (using the eddy correlation technique) at low altitudes and low airspeeds that are not feasible with airplanes, yet are quite valuable for studying the exchanges between the Earth's surface and the atmosphere. The main objective of this paper is to introduce the Duke HOP capability, emphasizing the range of airspeeds at which practically undisturbed air can be sampled in front of its nose, where its sensors and inlets are attached. Analytical, numerical, and observational studies are used for this purpose. In addition to the current sensors, an aerosol lidar and an atmospheric chemistry package are being mounted on the Duke HOP and they will be available for upcoming field campaigns. The Duke HOP was used in three field campaigns in 2007 and it is scheduled to participate in others in the near future. It is available to service the scientific community. © 2009 American Meteorological Society.