まろけちゃんねる。Maroke’s Channelさんが、2010-09-20 03:45:56に公開した『mini tornado at sports day!』は、動画ニュースnetがYoutubeから厳選して紹介している動画ニュースです。
（動画の元ページはこちらからご覧ください。）
☆タイトル：mini tornado at sports day!
☆投稿者：まろけちゃんねる。Maroke’s Channel
☆公開日：2010-09-20 03:45:56
☆視聴時間：1:52
☆視聴回数：1244337
Mini tornado or dust devil just at lunch time at Japan’s high school.
http://youtu.be/__U2D8WHDYE You can catch the TV NEWS here at this SECRET LINK!
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日本の体育祭の時に起こった竜巻のような大きな塵旋風です。
wikipedia
A tornado is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as a twister or a cyclone,[1] although the word cyclone is used in meteorology in a wider sense, to name any closed low pressure circulation. Tornadoes come in many shapes and sizes, but are typically in the form of a visible condensation funnel, whose narrow end touches the earth and is often encircled by a cloud of debris and dust. Most tornadoes have wind speeds less than 110 miles per hour (177 km/h), are approximately 250 feet (76 m) across, and travel a few miles (several kilometers) before dissipating. The most extreme tornadoes can attain wind speeds of more than 300 mph (480 km/h), stretch more than two miles (3.2 km) across, and stay on the ground for dozens of miles (more than 100 km).[2][3][4]
Various types of tornadoes include the landspout, multiple vortex tornado, and waterspout. Waterspouts are characterized by a spiraling funnel-shaped wind current, connecting to a large cumulus or cumulonimbus cloud. They are generally classified as non-supercellular tornadoes that develop over bodies of water.[5] These spiraling columns of air frequently develop in tropical areas close to the equator, and are less common at high latitudes.[6] Other tornado-like phenomena that exist in nature include the gustnado, dust devil, fire whirls, and steam devil.
Tornadoes have been observed on every continent except Antarctica. However, the vast majority of tornadoes in the world occur in the Tornado Alley region of the United States, although they can occur nearly anywhere in North America.[7] They also occasionally occur in south-central and eastern Asia, the Philippines, south east Asia, like Malaysia,[8] northern and east-central South America, Southern Africa, northwestern and southeast Europe, western and southeastern Australia, and New Zealand.[9] Tornadoes can be detected before or as they occur through the use of Pulse-Doppler radar by recognizing patterns in velocity and reflectivity data, such as hook echoes, as well as by the efforts of storm spotters.
Dust devil
A dust devil or dustnado is a strong, well-formed, and relatively long-lived whirlwind, ranging from small (half a metre wide and a few metres tall) to large (more than 10 metres wide and more than 1000 metres tall). The primary vertical motion is upward. Dust devils are usually harmless, but can on rare occasions grow large enough to pose a threat to both people and property.[1]
They are comparable to tornadoes in that both are a weather phenomenon of a vertically oriented rotating column of air. Most tornadoes are associated with a larger parent circulation, the mesocyclone on the back of a supercell thunderstorm. Dust devils form as a swirling updraft under sunny conditions during fair weather, rarely coming close to the intensity of a tornado.塵旋風（じんせんぷう）とは、地表付近の大気が渦巻状に立ち上る突風の一種である。一般的には旋風（せんぷう、つむじかぜ）や辻風（つじかぜ）と呼ばれ、英語ではダストデビルと呼ばれる。竜巻と似ていることから誤認されることも多いが、塵旋風と竜巻は根本的に異なる気象現象である。塵旋風（じんせんぷう）とは、地表付近の大気に上昇気流が発生し、これに水平方向の強風が加わるなどして渦巻状に回転しながら立ち上る突風の一種である。乾燥した土や砂などの埃、細かい落ち葉やゴミといった粉塵（ふんじん）が激しく舞い上がることから塵旋風と呼ばれる。晴天で強風の日などに荒地・空き地・田畑・運動場・駐車場などのある程度の広さがある場所で発生しやすく、小規模な塵旋風であれば日常生活の中でも比較的容易に見ることができる。しかし、ごく稀に大規模な塵旋風が発生して人や建物などに被害を及ぼすこともある。
塵旋風は、一般的な日本語では「旋風」（せんぷう、つむじかぜ）や「辻風」（つじかぜ）と呼ばれ、ニュースや天気予報などでは「塵」（じん）という漢字を平仮名にして「じん旋風」と表記することもある。英語では「ダストデビル」（Dust devil）と呼ぶことが一般的で「埃の悪魔」という意味だが、「ダストワール」（Dust whirl）と呼ぶこともある。