Introduction

The ELDORA (for ELectra DOppler RAdar) radar is an airborne, dual beam, meteorological research radar that was developed jointly at the National Center for Atmospheric Research (NCAR) in the USA and the Centre de Recherches en Physique de L'Environnement Terrestre et Planetaire (CRPE) in France. This radar is called the Analyse Stereoscopic par Radar Aeroporte sur Electra (ASTRAIA) by CRPE. The first field project for this radar was in the Solomon Islands during January and February of 1993.

The radar mounts on a Lockheed P-3 aircraft, operated by the Naval Research Lab (NRL). Its two antennas extend back from the tail of the aircraft and spin about the longitudinal axis of the aircraft. One antenna points slightly ahead of the aircraft and one slightly aft. As the aircraft translates the antennas through space the radar traces two conical helixes through the atmosphere, essentially observing all of the atmosphere with two separate looks within 50-100 kilometers of the aircraft at resolutions finer than 400 meters.

These two separate looks yield two wind vectors at each location in the atmosphere. Post acquisition analysis software is then used to combine these two wind vectors and, using a set of assumed initial conditions and applying the conservation of momentum and mass, produce a three dimensional "picture" of the atmosphere. This picture can then be sliced through any axis to produce two dimensional plots of the atmosphere.