南半球環(huán)狀模年際與年代際變化的調(diào)控機(jī)理及其對Supergyre Circulation的影響
發(fā)布時間:2018-03-29 23:37
本文選題:SAM 切入點:ENSO 出處:《中國海洋大學(xué)》2014年博士論文
【摘要】:厄爾尼諾現(xiàn)象的發(fā)生帶來全球平均溫度的升高,同時導(dǎo)致南半球環(huán)狀模變?yōu)樨?fù)位相。厄爾尼諾的這種媒介作用,使得南半球環(huán)狀模與全球平均溫度在年際尺度上表現(xiàn)為負(fù)相關(guān)。然而,當(dāng)溫室效應(yīng)主導(dǎo)的全球變暖發(fā)生時,全球平均溫度呈現(xiàn)上升趨勢,南半球環(huán)狀模也趨向于向正位相發(fā)展,這使得兩者呈正相關(guān)關(guān)系。這種變化趨勢上的正相關(guān)性會削弱厄爾尼諾周期中兩者的負(fù)相關(guān)性甚至使其徹底顛覆為正相關(guān)關(guān)系。由于ENSO強(qiáng)度的變化,在20世紀(jì)南半球夏季,全球平均溫度和南半球環(huán)狀模的關(guān)系呈現(xiàn)出非常明顯的年代際振蕩。在1925-1955年期間,ENSO強(qiáng)度的減弱使得全球平均溫度和南半球環(huán)狀模的負(fù)相關(guān)性變?nèi)。?970年之后,雖為ENSO強(qiáng)度的強(qiáng)烈期,但全球平均溫度和南半球環(huán)狀模的負(fù)相關(guān)性依然呈減弱趨勢。深入分析表明,1970年之后兩者相關(guān)性的下降是由全球氣候變化導(dǎo)致的,這同時突出了一個非常罕見的現(xiàn)象,亦即,氣候變化導(dǎo)致的兩者變化趨勢的相關(guān)性完全跟兩者在年際尺度上具有的相關(guān)性相反,突出了溫室氣體排放導(dǎo)致的全球變暖對氣候的影響。 在近幾十年內(nèi),除了溫室氣體的排放外,南極臭氧層臭氧消耗同樣對南半球環(huán)狀模產(chǎn)生了非常顯著的正位相變化趨勢,在海洋環(huán)流中表現(xiàn)為副熱帶地區(qū)的supergyre circulation向南移動并加強(qiáng)。其中,臭氧消耗的強(qiáng)迫作用對臭氧消耗時期(1961-2005年)南半球中高緯度環(huán)流場的變化趨勢起到了主導(dǎo)作用,然而,南極臭氧層在蒙特利爾協(xié)約的簽訂后開始逐漸恢復(fù)并預(yù)計在21世紀(jì)中期完全恢復(fù)。臭氧層臭氧恢復(fù)同臭氧層臭氧消耗對南半球中高緯度的作用是相反的,因此,臭氧含量的恢復(fù)對南半球副熱帶環(huán)流的作用對溫室氣體所起到的作用提供了一種抵消機(jī)制。那么這種抵消機(jī)制中,臭氧層臭氧的恢復(fù)能夠起到什么程度的作用?相對溫室氣體的排放,其作用占主導(dǎo)嗎?本文利用CMIP5模型組中中等溫室氣體排放量(RCP4.5)以及高等溫室氣體排放量(RCP8.5)控制實驗輸出的模式結(jié)果對這些問題進(jìn)行研究。兩組控制實驗都包含了臭氧恢復(fù)所起到的作用。本文顯示出在臭氧恢復(fù)期間(2006-2045),臭氧恢復(fù)對南半球夏季副熱帶環(huán)流(Subtropical gyre,三個大洋各自的副熱帶環(huán)流是彼此相連的,又被稱為Supergyre circulation)的影響基本可以抵消較溫室氣體排放對其的影響,以致該副熱帶環(huán)流在經(jīng)向上并沒有表現(xiàn)出向南極方向上的移動,而在臭氧層消耗時期以及高等溫室氣體排放量控制實驗下的臭氧層恢復(fù)后時期(2046-2100年),該副熱帶環(huán)流的南向移動是非常顯著的。同時,在2006-2045年南半球冬季,在高等溫室氣體排放量控制實驗下,結(jié)果顯示副熱帶環(huán)流呈現(xiàn)明顯的南移趨勢。在2006-2045年臭氧層恢復(fù)時期存在的這種季節(jié)變化同20世紀(jì)末幾十年內(nèi)所表現(xiàn)出來的季節(jié)變化趨勢是完全相反的。此外,在臭氧層臭氧恢復(fù)后時期,,在沒有臭氧層臭氧的作用下,副熱帶環(huán)流的經(jīng)向移動沒有表現(xiàn)出明顯的季節(jié)變化,這是因為此時的主導(dǎo)作用是溫室氣體的排放,然而溫室氣體排放量的不同,對副熱帶環(huán)流的經(jīng)向移動的影響是顯著不同的。在中等排放量情景下,副熱帶環(huán)流表現(xiàn)出穩(wěn)定的態(tài)勢,而在高等排放量情景下,副熱帶環(huán)流表現(xiàn)出明顯的南向移動,兩種變化趨勢的顯著不同突出了溫室氣體的排放對南半球環(huán)流場的影響,在南半球環(huán)狀模上亦有直接體現(xiàn)。
[Abstract]:El Nino has increased the average global temperature, which leads to the Southern Hemisphere annular mode becomes negative phase. This role of El Nino, the Southern Hemisphere annular mode and the average global temperature on the interannual scale are negatively related. However, when the greenhouse effect leading to global warming occurs, the average global temperature rising trend, the Southern Hemisphere annular mode also tend to develop to the positive phase, which makes both the positive correlation between the positive correlation. This trend will weaken the negative correlation between the cycle of El Nino and even to completely subvert the positive relationship. Because of the change of ENSO intensity in the southern hemisphere in summer twentieth Century, the relationship between the global average temperature and the Southern Hemisphere annular mode exhibits a decadal oscillation very obvious. During the 1925-1955 years, weakened the strength of ENSO makes the global average temperature and the southern hemisphere ring A negative correlation between the form becomes weak. After 1970, although the strong strength of ENSO, but a negative correlation between the average global temperature and the Southern Hemisphere annular mode still decreased. Further analysis shows that in 1970 after falling correlation is caused by the global climate change, it also highlights a very rare that is, the correlation between the phenomenon of climate change caused by the change of the two exactly on the interannual scale has the opposite, highlights the effects of global warming caused by greenhouse gas emissions on the climate.
In recent years, in addition to greenhouse gas emissions, the Antarctic ozone ozone depletion also had a positive phase change trend is very significant for the Southern Hemisphere annular mode, in the ocean circulation in the subtropical region of the supergyre circulation moved south and strengthened. The period of forcing ozone depletion of the ozone consumption (1961-2005 the change trend of years) in the southern hemisphere high latitude circulation plays a leading role, however, the Antarctic ozone layer in Montreal signed a treaty to gradually recovered and is expected to fully recover in mid twenty-first Century. Ozone ozone recovery with ozone ozone consumption is on the contrary, the effect of high latitude of the southern hemisphere in the ozone the content on the recovery of the Subtropical Gyre in the southern hemisphere on greenhouse gases which play an important role in providing an offsetting mechanism. Then this offset mechanism, the ozone layer of ozone Recovery can play to what extent? The relative emissions of greenhouse gases, the dominant? Using the medium of greenhouse gas emissions in the CMIP5 model group (RCP4.5) and higher emissions of greenhouse gases (RCP8.5) the mode control output of experiment on these problems were studied. Two control experiments are included the role played by ozone recovery. This paper shows the recovery period in the ozone, ozone (2006-2045) on the recovery of the Subtropical Gyre in the southern hemisphere summer (Subtropical gyre, the subtropical circulation of each of the three oceans are connected to each other, also known as Supergyre circulation) the effect can affect the offset a greenhouse gas discharge, so that the Subtropical Gyre in the meridional direction and showed no moves toward the direction of the Antarctic, and in the ozone layer depletion period and higher greenhouse gas emissions under the control of ozone experiment Layer recovery period after (2046-2100 years), the subtropical south movement is very significant. At the same time, in the 2006-2045 years of the southern hemisphere winter, higher in greenhouse gas emissions control experiment, results showed that the subtropical gyre showed obvious seasonal variation trend with the southward trend. At the end of twentieth Century decades has shown recovery the seasonal variation in the 2006-2045 year period of existence of the ozone layer is completely opposite. In addition, in the period of ozone ozone recovery, no effect in the ozone layer of ozone, the subtropical meridional movement showed no obvious seasonal changes, this is because the leading role of the greenhouse gas emissions however, greenhouse gas emissions, to move to the subtropical circulation is significantly different. In secondary emission scenarios, the subtropical circulation showed a stable trend, and in the higher Under the scenario of emission, the subtropical circulation shows obvious southward movement. The two trends are significantly different, highlighting the influence of greenhouse gas emissions on the southern hemisphere circumferential flow field, and also directly reflect the annular modes in the southern hemisphere.
【學(xué)位授予單位】:中國海洋大學(xué)
【學(xué)位級別】:博士
【學(xué)位授予年份】:2014
【分類號】:P731.27
【參考文獻(xiàn)】
相關(guān)博士學(xué)位論文 前1條
1 宮婷婷;南半球環(huán)狀模與ENSO的關(guān)系研究[D];中國海洋大學(xué);2009年
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