在高高的平流層上,一股旋風(fēng)刮過(guò),也許很少有人注意到,這股高空旋轉(zhuǎn)氣流可能會(huì)攪動(dòng)海洋深處。新巨型計(jì)算機(jī)模擬效果顯示,平流層旋風(fēng)在攪動(dòng)地球海洋的同時(shí)也能幫助塑造全球氣候。
科學(xué)家曾指出,距離地面10公里到50公里的平流層的活躍程度會(huì)對(duì)其下的對(duì)流層產(chǎn)生一定影響。他們還了解到,對(duì)流層能影響海洋的環(huán)流模式,從而帶來(lái)天氣的變化。
而今年早些時(shí)候發(fā)表的相關(guān)研究報(bào)告曾暗示,平流層中發(fā)生的氣象事件也可能直接影響海洋,但是這些發(fā)現(xiàn)主要基于一個(gè)簡(jiǎn)單的氣候模型和計(jì)算機(jī)模擬——僅僅建模了相對(duì)較短的260年內(nèi)的平流層。
通過(guò)深入研究有關(guān)平流
首次證實(shí)平流層直接影響地球氣候
在高高的平流層上,一股旋風(fēng)刮過(guò),也許很少有人注意到,這股高空旋轉(zhuǎn)氣流可能會(huì)攪動(dòng)海洋深處。新巨型計(jì)算機(jī)模擬效果顯示,平流層旋風(fēng)在攪動(dòng)地球海洋的同時(shí)也能幫助塑造全球氣候。
科學(xué)家曾指出,距離地面10公里到50公里的平流層的活躍程度會(huì)對(duì)其下的對(duì)流層產(chǎn)生一定影響。他們還了解到,對(duì)流層能影響海洋的環(huán)流模式,從而帶來(lái)天氣的變化。
而今年早些時(shí)候發(fā)表的相關(guān)研究報(bào)告曾暗示,平流層中發(fā)生的氣象事件也可能直接影響海洋,但是這些發(fā)現(xiàn)主要基于一個(gè)簡(jiǎn)單的氣候模型和計(jì)算機(jī)模擬——僅僅建模了相對(duì)較短的260年內(nèi)的平流層。
通過(guò)深入研究有關(guān)平流
層和海洋之間的聯(lián)系,位于美國(guó)鹽湖城的猶他大學(xué)的氣象科學(xué)家Thomas Reichler和同事們重新考證了美國(guó)國(guó)家海洋和大氣管理局發(fā)明的一個(gè)著名的氣候模型得出的模擬結(jié)論,該氣候模型編輯了4000年里的大氣和海洋條件,并且將其與過(guò)去30年里收集的天氣和海洋數(shù)據(jù)進(jìn)行了比較。新研究結(jié)果顯示,平流層風(fēng)和海浪下方2千米的洋流之間有著令人驚訝的聯(lián)系。研究人員近期在《自然—地球科學(xué)》網(wǎng)絡(luò)版上報(bào)告了利用氣候模型得出的這一新發(fā)現(xiàn)。研究人員指出,平均每?jī)赡昶搅鲗訒?huì)被突然加熱幾十度,這樣一來(lái),時(shí)速130公里的平流層風(fēng)形成的極地渦旋環(huán)繞著北極地區(qū),這種極渦在兩個(gè)月里能減弱或者改變方向——圍繞北極點(diǎn)由逆時(shí)針?lè)较蜃優(yōu)轫槙r(shí)針?lè)较?。同時(shí),科學(xué)家得出的氣候模型顯示,幾十年來(lái),這些變暖事件戲劇性地?cái)_亂著海洋表面,影響著大西洋經(jīng)圈翻轉(zhuǎn)環(huán)流的流動(dòng)。大西洋經(jīng)圈翻轉(zhuǎn)環(huán)流就像一個(gè)傳送帶,將海水圍繞地球傳送。
“平流層產(chǎn)生的這些影響能夠解釋我們?cè)诤Q笾邪l(fā)現(xiàn)的大約30%的振動(dòng)?!盧eichler說(shuō),“我們發(fā)現(xiàn)大西洋經(jīng)圈翻轉(zhuǎn)環(huán)流存在一個(gè)‘阿喀琉斯之踵’:格陵蘭島南部的北大西洋上的一個(gè)地區(qū)極為脆弱?!边@個(gè)地區(qū)對(duì)于來(lái)自大氣的即使輕微地加溫或冷卻都十分敏感——海水的溫度影響其下沉的幅度,從而導(dǎo)致驅(qū)動(dòng)或延緩海洋傳送帶?!拔覐奈纯紤]過(guò)數(shù)千公里高的大氣中的天氣事件會(huì)深遠(yuǎn)影響著海洋深處?!泵绹?guó)大氣和環(huán)境研究所的氣象學(xué)家Judah Cohen表示,“這項(xiàng)研究是對(duì)天氣系統(tǒng)驚人復(fù)雜性的又一例證,各個(gè)部分之間如何關(guān)聯(lián)使得對(duì)其進(jìn)行模擬極為困難?!?/p>
另外,這些發(fā)現(xiàn)暗示,氣候模型的建立不能像以往一樣忽略平流層的作用。但是,Reichler警告說(shuō),目前尚不清楚平流層對(duì)于天氣的影響到底有多大。另一方面,平流層爆發(fā)性增溫事件是由對(duì)流層上升氣流驅(qū)動(dòng)的,“因此,有人認(rèn)為對(duì)流層是所有事件的原發(fā)性原因?!?Reichler提到,“我認(rèn)為平流層對(duì)這些來(lái)自對(duì)流層的氣流影響進(jìn)行了擴(kuò)大,才最終影響了海洋,但是,這一問(wèn)題還需要進(jìn)一步研究確定?!?/p>
Stratosphere wind changes affect seas and climate, study shows
Changes in the winds high in the stratosphere aff ect the seas and climate, according to a new study.The research from the University of Utah study suggests changes in winds from 15-30 miles up hit at a vulnerable "Achilles heel" in the North Atlantic and alter miledeep sea circulation patterns that change the weather.The findings have been published in the online journal Nature Geoscience.
Senior author Thomas Reichler says, "We found evidence that what happens in the stratosphere matters for the ocean circulation and therefore for climate."
It was already realised that changes in the stratosphere, between 6-30 miles above Earth, affect what happens in the troposphere, which stretches from Earth's surface up to six miles or about 32,800 feet up and where weather occurs.
It was also known that global circulation patterns in the seas, caused mainly by changes in water temperature and saltiness, infl uence global climate.
Associate professor of atmospheric sciences at the university, Thomas Reichler, says, "It is not new that the stratosphere impacts the troposphere.It also is not new that the troposphere impacts the ocean.But now we actually demonstrated an entire link between the stratosphere, the troposphere and the ocean."
Thomas Reichler carried out the research with University of Utah atmospheric sciences doctoral student Junsu Kim, atmospheric scientist Elisa Manzini and oceanographer Jürgen Kr?ger, from the Max Planck Institute for Meteorology based in Hamburg, Germany.The study was fi nanced by the University of Utah.
The team used weather observation data supercomputer simulations of 4,000 years of weather to reveal a surprising association between decade-scale, alterations in stratospheric wind patterns called the polar vortex, and rhythmic differences in deepsea circulation patierns.