[:ja]ルカ・パルミタノ宇宙飛行士がISSから撮影した南大西洋に浮かぶイギリス領の火山島セントヘレナ島です。障害物（島）と風の関係で、画像のように雲を遮る様子がわかりますが、稀にカルマン渦が形成されることがあります。カルマン渦は、流れのなかに置かれた障害物を動かした時、その後方に交互にできる渦の列のことで、自然現象では、島の風下側に雲渦が形成されることがあります。
セントヘレナ島は、アフリカ大陸から2,800 km離れた孤島で、人口は約4,000人。ナポレオン1世幽閉の地として知られています。過去には、スエズ運河完成まではインド洋に向かう航路上の要衝であり、給水地として用いられていました。主な経済活動は漁業、家畜農園、手工芸品ですが、これだけでは全住民の生活を支えられず、不完全雇用がセントヘレナの大きな問題となっています。実際、公的セクターがGDPの50%を占めています。観光業はナポレオンの流刑により有名で、また、ゴルフやスポーツフィッシングも盛んです。
地上の様子はこちらです。
参考文献： Luca Parmitano’s Tweet
地球俯瞰画像を見る： LiVEARTH
[Earthview Wonders] No.1182: Island of Saint Helena🇸🇭
Astronaut Luca Parmitano captured from ISS the Saint Helena, a volcanic tropical island in the South Atlantic Ocean and the British Overseas Territory. As shown in the image, the flow of atmospheric air over obstacles such as islands or isolated mountains sometimes gives birth to von Kármán vortex streets. When a cloud layer is present at the relevant altitude, the streets become visible.
Saint Helena is 2,800km off the coast of Africa and has about 4,000 population. It is one of the most remote islands in the world, and was uninhabited when discovered by the Portuguese in 1502. It was an important stopover for ships sailing to Europe from Asia and South Africa for centuries before Suez Canal was constructed. The island’s economy is now weak, and is almost entirely sustained by aid from the British government. The public sector dominates the economy, accounting for about 50% of gross domestic product. The tourist industry is heavily based on the promotion of Napoleon’s imprisonment. A golf course also exists and the possibility for sportfishing tourism is great.
The local scenery on the ground is as follows.
Reference: Luca Parmitano’s Tweet
See earthview photo gallery: LiVEARTH[:en][Earthview Wonders] No.1182: Island of Saint Helena🇸🇭
Astronaut Luca Parmitano captured from ISS the Saint Helena, a volcanic tropical island in the South Atlantic Ocean and the British Overseas Territory. As shown in the image, the flow of atmospheric air over obstacles such as islands or isolated mountains sometimes gives birth to von Kármán vortex streets. When a cloud layer is present at the relevant altitude, the streets become visible.
Saint Helena is 2,800km off the coast of Africa and has about 4,000 population. It is one of the most remote islands in the world, and was uninhabited when discovered by the Portuguese in 1502. It was an important stopover for ships sailing to Europe from Asia and South Africa for centuries before Suez Canal was constructed. The island’s economy is now weak, and is almost entirely sustained by aid from the British government. The public sector dominates the economy, accounting for about 50% of gross domestic product. The tourist industry is heavily based on the promotion of Napoleon’s imprisonment. A golf course also exists and the possibility for sportfishing tourism is great.
The local scenery on the ground is as follows.
Reference: Luca Parmitano’s Tweet
See earthview photo gallery: LiVEARTH[:]