segunda-feira, abril 19


"On the evening of April 16th, there were some small eruptions producing ash clouds up to about 6-7 km, with lightning," says photographer Harald Edens. "The sky was nice and clear, so I was able to photograph the bolts from the town of Hvolsvollur using my Nikon D700 and a 80-200/2.8 lens."

It is well known that volcanic eruptions produce strong lightning. Less well known is why? Ordinary lightning in thunderstorms is not fully understood; volcanic lightning is even more of a mystery.To investigate, a team of researchers from New Mexico Tech has traveled to Iceland to monitor the Eyjafjallajokull volcano--and they have found it crackling with electricity.

Photography is one way to monitor volcanic lightning, but the technique has limits: Ash clouds are able to hide the flashes; lightning is not always visible in daylight; glowing lava competes for attention; and so on. Radio receivers can do a better job. Lightning emits impulsive radio bursts which can be measured and counted, day or night, even through clouds of ash. "We are deploying a six-station lightning array around the Eyjafjallajokull volcano," says Edens. Their analysis of the radio "crackles" could reveal much about the inner workings of volcanic lightning.

3 Comentários:

Às 19 abril, 2010 12:57 , Blogger bluegift disse...

Não sabia. As imagens desse site são fantásticas! permite-me deixá-lo aqui: relâmpagos no Eyjafjallajoekull, Islandia

Às 19 abril, 2010 16:26 , Blogger antonio - o implume disse...

Este vulcão é particularmente mal disposto...

Às 20 abril, 2010 19:15 , Blogger Peter disse...

Um vulcão na Islândia entrou em actividade, cobrindo o céu de cinzas. Um fenómeno da natureza, que muitos julgavam já ter sido dominada pela ciência e pela técnica. Afinal, a natureza mostra a sua força e exige maior humildade da nossa parte. O Governo português encontra aqui um argumento em favor do TGV, que anda tão precisado de justificações.


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