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ELDORA (ELectra DOppler RAdar)

ELDORA is an airborne, dual beam, meteorological research radar developed jointly at the National Center for Atmospheric Research (NCAR), USA, and the Centre de Recherches en Physique de L’Environnement Terrestre et Planetaire (CETP), France.

ELDORA mounts on NCAR’s Lockheed Electra aircraft. Its two antennas extend back from the tail of the aircraft and spin about the longitudinal axis of the aircraft. One antennae points slightly ahead of the aircraft, and one slightly aft. As the aircraft translates the antennas through space, ELDORA traces two conical helixes through the atmosphere, essentially observing the atmosphere with two separate looks within 50-100 kilometers of the aircraft. The fore and aft looks from ELDORA yield two wind components for each location in the atmosphere. Applying the conservation of momentum and mass, a three-dimensional structure of the atmosphere is produced which can then be sliced through any axis to produce two-dimensional plots.

The ELDORA radar system consists of five major functional blocks: the RF signal generator / receiver unit, the TWT high power amplifiers, the signal processor, the antenna / rotodome system, and the radar control equipment. Since the radar system consists of two separate fore- and aft-pointing radars much of the hardware contains two identical modules. Only the basic signal generation equipment and the radar control equipment do not contain duplicate modules.

The ELDORA output variables include radar reflectivity, mean radial velocity, spectral width, and normalized coherent power. These data are passed to the data recording and display system, thus enabling the data system to receive all data from both the fore and the aft radars, to tag it with aircraft position information and to record and display the data. ELDORA’s first deployment was to TOGA COARE in the Solomon Islands in January and February 1993.


National Center for Atmospheric Research (NCAR)

Centre de Recherches en Physique de L’Environnement Terrestre et Planetaire (CRPE)

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