文:Alex
黃昏日落時段被稱為魔幻時刻(Magic hour),名字當真無花無假。金黃色或者火紅色「Magic hour」大家都見過不少,但翠綠色的天空大家又見過未?
GOODNESS GREEN. This is a look at the sky in Sioux Falls right now as severe storms push through from one of the DOT cams. #SDwx @foxweather pic.twitter.com/VhSEvxpE1D
— Heather Brinkmann (@WeatherHx) July 5, 2022
在當地時間周二傍晚,強烈風暴穿越美國南達科他州的蘇福爾斯(Sioux Falls)市,天空烏雲密布之餘,其中一片天空還發出詭異的綠色光芒。由街道攝影機及市民拍到的影像所見,當時的景況活像華人傳統文化習俗裡經常提到的陰曹地府,氣氛令人不寒而慄!
Have never seen something like that.
— Aafaque (@aafaque33) July 5, 2022
Green sky with combination of blue in Sioux falls SD#sdwx pic.twitter.com/aAq5G2K9Xb
Sioux Falls, SD #sdwx pic.twitter.com/uH8hRKbA4G
— Nathen Erickson (@TwstdSkyStudios) July 6, 2022
其實綠色的天空既與夕陽有關,風暴雲的成分也是關鍵。據解獨,來自夕陽的光線經過大氣散射而變成橙紅色,形成我們平時常見的橙紅色彩霞;夕陽越接近地平線,彩霞的色調越深。另一方面,風暴雲若含有極大量水或冰微粒,這些微粒同樣因光線散射的緣故,看起來會呈現淺藍色。若以上兩者結合,讓橙紅色的光線照向淺藍色的水或冰微粒,就會出現如今見到的綠色天空(風暴雲)。
The approach. @NWSSiouxFalls @keloland @dakotanews_now pic.twitter.com/NOl35jIlpt
— jaden ? ? (@jkarmill) July 5, 2022
事實上,當綠色雲出現,往往是落雹的先兆。據新聞報導,當地收到不少落雹報告,冰雹最大有如高爾夫球至網球般大小,而國家氣象局則指大部分冰雹的直徑都在 1 吋內。
Just before the rain and hail started in Southeast Sioux Falls. Stay safe out there, everyone. #sdwx @NWSSiouxFalls pic.twitter.com/pguPmnEmAO
— Jay Elsen - Midco Sports (@ElsenMidco) July 5, 2022
侵襲蘇福爾斯的風暴由西面進入。該市部分地區錄得最高風速超過每小時 159 公里,降雨量超過 76mm。風暴又切斷電力供應,讓南達科他州約 28,000 多人無電力供應,幸好周二晚即恢復向 20,000 人供電。該風暴其後繼續向東移動,進入明尼蘇達州西南部和愛荷華州西北部。
Pics of the green sky from my family in Sioux Falls have been incredible! Had to dig up this fun green cloud infographic I made back in the day. Hail reports not too large at the moment, but storms are very moisture loaded in this warm, tropical environment. #SDwx #IAwx pic.twitter.com/S39JLSRfEu
— Cory Martin (@cory_martin) July 5, 2022
Timelapse of frightening thunderstorm just passed from #SiouxFalls#sdwx #wx #weather #THUNDERSTORM pic.twitter.com/FHPHs0iKuM
— Aafaque (@aafaque33) July 5, 2022
來源:Fox Weather