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xinhua news agency, beijing, september 12 (xinhua) -- british researchers have analyzed meteorological observation data for about 40 years and found that the position of the high-altitude jet stream over the north pacific is shifting toward the arctic, which has been particularly evident in the past decade. this phenomenon may be caused by climate warming, which will make extreme weather more frequent in the western united states, the european mediterranean and other regions.

the high-altitude jet streams are several strong high-speed air currents that surround the earth. they are generated by the rotation of the earth and the temperature difference between the equator and the poles. they carry heat and moisture at high speed and have an important impact on the climate. they are about 9 to 10 kilometers above the surface, flowing from west to east, like several narrow and curved ribbons, winding around the subtropical and mid- and high-latitude regions in the northern and southern hemispheres.

meteorological models show that as the world warms, the high-altitude jet streams in the two hemispheres will shift toward the north pole and the south pole, respectively. however, due to uncertainties in the location definition of the high-altitude jet streams and data statistical methods, this phenomenon has not been confirmed by observational data.

researchers from the university of reading in the uk and other institutions used four meteorological databases from europe, japan and the united states to analyze the changes in wind speed over the north pacific from 1980 to 2023, and found that the position of the north pacific high-altitude jet stream in winter has a significant northward shift, with a range of about 30 to 80 kilometers every 10 years. the relevant paper was published in the american academic journal geophysical communications.

the analysis also shows that based on the current trend, if global carbon emissions remain at a high level, the position of the north pacific jet stream in winter will move further north by the end of the 21st century, and its position in autumn will also be affected. studying the changes in the position of this jet stream is of great significance for understanding the climate in the mid-latitude regions of the northern hemisphere in the 21st century. (end)