科學家好像發現了今年熱浪不斷的原因

Scientists have discovered a new link between a pattern of fluctuations in jet stream air currents and crippling heatwaves that strike in multiple regions of the world at the same time.

科學家發現噴流的波動模式和同時襲擊世界上多個地區的嚴重熱浪之間的新聯繫。

Rossby waves are an atmospheric and oceanic phenomenon where giant meanders warp the flow of currents in a wave-like pattern. They don't only occur on Earth, but when they do, they're known to influence our planet's weather.

羅斯貝波是一種大氣和海洋現象，巨大的蜿蜒曲折會使氣流呈波浪狀彎曲。它們不僅會發生在地球上，而且已知出現的時候會影響地球的天氣。

Now, the extent of that influence is becoming clearer. In a new study, researchers have found that when certain amplified wavelengths take shape in jet streams – fast-flowing air currents that course through the sky at high altitudes – the phenomenon is linked to the emergence of concurrent heatwaves that devastate food-producing regions.

現在，這種影響的程度越來越明顯。在一項新的研究中，研究員發現，當特定的放大波長在噴流--高海拔時經過天空的快速流動的氣流--中成形時，這種現象與同時出現的破壞食品生產地區的熱浪有關。

"We found a 20-fold increase in the risk of simultaneous heatwaves in major crop-producing regions when these global-scale wind patterns are in place," says Earth systems researcher Kai Kornhuber from Columbia University.

“我們發現，這些全球規模的風型出現時，主要糧食生產地同時出現熱浪的風險增加了20倍。”哥倫比亞大學的地球系統研究員凱·科恩哈伯（Kai Kornhuber）說道。

Kornhuber and his team analysed climate data from 1979 to 2018 and found that when two particular wavelengths of circumglobal Rossby waves – called wave–5 and wave–7 – occurred in the Northern Hemisphere jet stream, they channel hot subtropical air into regions in North America, Europe, and Asia.

科恩哈伯和他的團隊分析了1979年至2018年的氣候數據，發現當環地羅斯貝波的兩股特定波長波-5和波-7出現在北半球的噴流中時，會將亞熱帶熱空氣引入北美、歐洲和亞洲地區。

The hot air produces temperature spikes that can persist for weeks: extreme weather events that kill people, and threaten global food security through the widespread impact they have on crops.

熱空氣會產生持續數週的溫度峯值。極端天氣會致人死亡，並通過對莊稼造成影響而威脅全球食品安全。