Wave clouds in the southern Indian Ocean The wake created in the winds by l'Ile aux Cochons (pig isl

Wave clouds in the southern Indian OceanThe wake created in the winds by l'Ile aux Cochons (pig island, a 775 metre volcano in the Crozet isles about halfway between South Africa and Antarctica) is beautifully captured in the cloud formations photographed by an astronaut on the space station. I’ve heard clouds described as the laws of physics drawing in the air and the complex scene here displays two layers of clouds demonstrating some of these forces interacting.The lower one is forming cloud streets (see http://tinyurl.com/q84zhjw) in response to the prevailing westerlies, while the higher one are orographic, formed as the moist winds pass over the island, cooling as they rise, and condensing the water vapour within into clouds. As the air masses fall back down again after the island, they encounter alternating layers of moist and dry air and form the chevron shaped clouds in the island’s wake. The clouds themselves are still, and merely mark in a visible sculpture the movements of the air masses and the interaction between humidity, altitude and temperature. The chevron clouds are forming where the air mass after passing over the island meets moist air, condensing it with its relative coolth from its recent journey to higher altitudes, while the dry regions remain free of visible cloud, since they have too little moisture to condense.LozImage credit: NASAhttp://earthobservatory.nasa.gov/IOTD/view.php?id=77729&src=fb -- source link

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