The Collaborative Colorado–Nebraska Unmanned Aircraft System Experiment (CoCoNUE) was executed on 1 March and 30 September 2009. The principal objective of this project was to examine the feasibility of using a small unmanned aircraft operating semi-autonomously with an onboard autopilot to observe atmospheric phenomena within the terrestrial boundary layer covered by the United States National Airspace System. The application of an unmanned aircraft system (UAS; the aircraft along with the communications and logistics infrastructure required for operation) is beset by a number of engineering and regulatory challenges. This article discusses the strategies implemented to meet these challenges.

Airmass boundaries served as the target of the flights conducted. These atmospheric phenomena have the fortuitous combination of an across-boundary scale that yields a coherent signal in the in situ meteorological data that can be collected by a UAS and an along-boundary scale that can be easily tracked via the existing network of synoptic-scale observations. Furthermore, airmass boundaries are readily apparent in radar data. Presented herein is a comparison of the in situ observations collected by the UAS to the dual-Doppler observations collected by proximity radars on 30 September. On this day the unmanned aircraft was flown across both a cold front and thunderstorm-generated gust front. The flights executed as part of CoCoNUE are thought to represent the first time that a UAS has been used to collect in situ observations of mesoscale phenomena in the lower atmosphere over land in the National Airspace System. The intent of this article is not only to demonstrate that a UAS can be used in this way but also to share the strategies that were adopted to overcome the many obstacles to conducting such an experiment.

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