A detecção de aves pelo radar na Segunda Guerra
The early development of radar was driven primarily by military imperatives, and the targets that were to be detected were mainly aircraft and ships. It was no surprise that echoes were also received from terrain and from rainstorms, but the discovery, during World War II, that birds were often detectable was less expected. As the technology developed, and specially after transmission at the shorter ‘microwave’ wavelengths became commonplace, echoes from insects were also identified. In the late 1940’s and the 1950’s, radar technology was adapted rapidly to the needs of meteorologists, while ornithologists pioneered the use of defence and air-traffic control radars to study bird migration.
Radar observations of insects, however, were relatively sparse until the early 1960’s, when radar meteorologists became rather intensely interested in a type of warm-weather echo that appeared, puzzlingly from their perspective, when there was not a cloud in sight. Perhaps spurred by the meteorologists’ observations, entomologists began their own exploitation of the technology in 1968, when a rather modest radar, built by G.W. Schaefer specifically for insect observation and operated in West Africa just south of the Sahara, proved to be very effective.
Fonte: DRAKE, V.A. and REYNOLDS, D.R. Radar Entomology: Observing Insect Flight and Mi- gration. CAB Internacional, 2012.
Fonte: Radar Entomology: Observing Insect Flight and Migration, de V. A. Drake e D. R. Reynolds (CAB International), 2012.
De acordo com o texto, uma descoberta que causou surpresa aos usuários de radares durante a Segunda Guerra Mundial foi a capacidade do radar em detectar
- A) características geográficas.
- B) fenômenos atmosféricos.
- C) grupos de aves.
- D) grupos de insetos.
- E) aeronaves e navios.