The jet stream's discoverer published his findings in Esperanto
In the 1920s, Wasaburo Oishi released weather balloons near Mount Fuji and tracked them as they rose into a fierce, steady wind high above Japan. He had found the jet stream, but he wrote up his results in Esperanto, so almost nobody outside Japan noticed. Credit for the discovery took decades to catch up.
Hints had surfaced earlier. The American professor Elias Loomis proposed in the 19th century that a powerful high-altitude current blowing west to east could explain how big storms travelled, and after Krakatoa erupted in 1883, observers tracked its haze moving around the globe. The aviator Wiley Post, who flew solo around the world in 1933 and devised a pressurised suit for high flight, is sometimes given partial credit. The German meteorologist Heinrich Seilkopf coined a term meaning jet current in 1939. Understanding really grew during the Second World War, when pilots flying from the United States to Britain kept meeting westerly tailwinds faster than 160 kilometres per hour.
The main jets are narrow ribbons of wind a few hundred kilometres wide and usually less than five kilometres deep. Polar jets circle each hemisphere at about 9 kilometres up, typically blowing around 180 kilometres per hour and sometimes far faster; speeds of 400 kilometres per hour have been measured. Weaker subtropical jets flow somewhat higher, closer to the equator. Both arise from the Sun heating the planet unevenly, which drives giant circulation cells, combined with the Coriolis effect of Earth's spin.
Rather than running straight, a jet meanders in huge loops called Rossby waves, which drift eastward more slowly than the wind inside them and can split off into eddies. Because the jet marks the boundary between cold polar air and warmer subtropical air, its position steers storms at ground level, making it central to weather forecasting. When the northern polar jet stayed unusually far south during the summers of 2007 and 2012, Britain suffered severe flooding. It also follows the seasons, moving north as the hemisphere warms and south as it cools.
Airlines plan around it, riding the flow eastbound to save time and fuel. Some meteorologists also credit the subtropical jet with helping shield Hawaii, since its wind shear can weaken approaching hurricanes. Jet streams are not unique to Earth; they have been detected on Venus, Jupiter, Saturn, Uranus and Neptune.
Source: Jet stream
