Opzich niet zo erg bijzonder dat deze worden gededecteerd door middel van echo's. Namelijk:
"Noctilucent clouds are known to exhibit high radar reflectivity,[9] in a frequency range of 50 MHz to 1.3 GHz.[12] This behaviour is not well understood but Caltech's Prof. Paul Bellan has proposed a possible explanation: that the ice grains become coated with a thin metal film composed of sodium and iron, which makes the cloud far more reflective to radar."
Wikipedia
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