The dielectric properties of cold, dry ice in the polar ice caps are favorable for the use of a radar technique in the rapid and continuous measurement of ice thickness from an aircraft. Feasibility and applicability to extended traverses have been demonstrated by a series of flights over the Greenland ice cap, in July 1966. Pulsed 30-MHz signals at a 20-kHz repetition frequency, 2.5-msec duration, 400-W peak power, 7-W average power, with A-scope presentation, were photographically recorded on 35-mm film with frequency-stabilized time and yielded very good results over four flights, comprising 9600 km total traverse. Maximum ice thickness recorded was approximately 3300 ± 50 m. The aircraft used was an EC-121-P (Super Constellation), flying 600 m above the air-ice interface at approximately 300 km/hr. Special problems of warm (wet) snow, antenna design, recording, and navigation are discussed.

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