The ELDORA/ASTRAIA airborne Doppler weather radar: goals, design, and first field tests

Describes the development and first operation of a innovative research tool for observing atmospheric storms: an airborne X-band Doppler radar. The radar has been built jointly by the National Center for Atmospheric Research (NCAR) in Boulder, CO and the Centre de Recherches en Physique de l´Environnement Terrestre et Planetaire (CRPE) in Paris, France. The radar is called ELDORA/ASTRAIA for Electra Doppler Radar/Analyse Stereoscopique par Radar Aeroporte sur Electra. The radar is designed to provide high-resolution measurements of the air motion and rainfall characteristics of very large storms: storms which are frequently too large and/or too remote to be adequately observed by ground-based radars. This paper includes discussions of the scientific impetus and design criteria as well as the engineering solutions to these design needs. The design options and tradeoffs of the resulting capabilities are discussed. The paper concludes with an evaluation of the performance of the system at its first field test, conducted as a part of the international global warming experiment in the equatorial Pacific Ocean known as the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE). This evaluation illustrates that the major design goals for the radar - collection of relatively noise-free velocity and reflectivity data using a rapid scanning radar - have been adequately met. Future options for further improvements to the radar are discussed