發(fā)布時(shí)間：2018-03-08 04:17

  本文選題：印度夏季降水　切入點(diǎn)：東亞夏季降水　出處：《南京信息工程大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

【摘要】：厄爾尼諾-南方濤動(dòng)(ENSO)作為全球最重要的海氣耦合現(xiàn)象,已被證實(shí)為可預(yù)報(bào)性來源之一,且對(duì)全球天氣氣候有深遠(yuǎn)的影響。Mega-ENSO于2013年由Wang等首次提出,是海表溫度變率的主模態(tài),具有多年代際時(shí)間尺度,從年際到年代際。Mega-ENSO的定義區(qū)域包含了熱帶太平洋以及太平洋的副熱帶區(qū)域。鑒于其有比傳統(tǒng)ENSO更為廣泛的時(shí)空尺度。Mega-ENSO指數(shù)可能比傳統(tǒng)ENSO包含了更豐富和復(fù)雜的氣候信息。例如,mega-ENSO是包含了印度夏季降水(ISR)、東亞夏季風(fēng)降水(EASR)在內(nèi)的北半球夏季風(fēng)降水的主要驅(qū)動(dòng)力,而這一作用并未在傳統(tǒng)ENSO中得到體現(xiàn)。季風(fēng)對(duì)農(nóng)業(yè)生產(chǎn)、水利用率和食品安全至關(guān)重要,其年際變率很大程度上影響農(nóng)業(yè)生產(chǎn),分布可以對(duì)糧食產(chǎn)量造成嚴(yán)重影響,反過來,對(duì)人口急劇增長的印度的食品安全產(chǎn)生威脅。因此,掌握季風(fēng)的新的預(yù)報(bào)因子、提高其預(yù)報(bào)技巧至關(guān)重要且必要。此外,ENSO和季風(fēng)是氣候系統(tǒng)中相互作用的兩個(gè)分量。由于ENSO的鎖相特征,夏季風(fēng)通常在其發(fā)展期或衰減期。然而,多數(shù)研究主要集中在傳統(tǒng)ENSO,且極少數(shù)關(guān)注其發(fā)展階段。運(yùn)用mega-ENSO指數(shù)的目的是獲取更多ENSO系統(tǒng)的完整信息。鑒于mega-ENSO是比傳統(tǒng)ENSO更加大范圍的變率,探究ISR及大氣環(huán)流是否響應(yīng)于mega-ENSO及傳統(tǒng)ENSO以及它們的不同聯(lián)系將會(huì)非常重要。這是本研究的出發(fā)點(diǎn)之一。本文主要比較了典型mega-ENSO-ISR和非典型ENSO-ISR的不同聯(lián)系。在典型El Nino發(fā)展期夏季,印度半島東北部降水負(fù)異常,而在典型La Nina發(fā)展期夏季,降水異常型幾乎線性相反；對(duì)于非典型ENSO,這一“線性相反”的現(xiàn)象消失。此外,在中緯度地區(qū)有一緯向異常波列,在典型mega-ENSO發(fā)展期夏季其局地響應(yīng)為歐亞大陸中東部的三極子環(huán)流型,這可能是相應(yīng)的印度次大陸降水異常的原因。相反的,這些特征在非典型ENSO的發(fā)展期夏季并不明顯。利用CMIP5 9個(gè)模式的106年歷史運(yùn)行結(jié)果(1900-2005),HadGEM2-ES表現(xiàn)了較好的對(duì)于異常環(huán)流型的模擬能力,而CanESM2較差。此外,我們還比較了典型mega-ENSO-EASR和非典型ENSO-EASR的在衰減期的不同聯(lián)系。在典型El Nino衰減期夏季,東亞地區(qū)降水三極子異常,而在典型La Nifla衰減期夏季,降水異常型線性相反；對(duì)于非典型ENSO,這一現(xiàn)象消失。此外,中緯度地區(qū)有一緯向異常波列在典型mega-ENSO衰減期夏季其局地響應(yīng)為歐亞大陸中東部的三極子環(huán)流型。相反的,在非典型ENSO的衰減期夏季主要的環(huán)流型出現(xiàn)在北太平洋。同樣利用CMIP5 9個(gè)模式結(jié)果,HadCM3表現(xiàn)了較好模擬能力,而CanESM2較差。此外,模式對(duì)于典型mega-ENSO-ISR、 ENSO-EASR聯(lián)系的模擬能力的差別還有可能源于其對(duì)典型mega-ENSO特征的模擬能力。
[Abstract]:El Nino Southern Oscillation (ENSO), as one of the most important coupled sea and air phenomena in the world, has been proved to be one of the most predictable sources, and has far-reaching influence on the global weather and climate. Mega-ENSO was first proposed by Wang et al in 2013, which is the main mode of sea surface temperature variability. With years of intergenerational time scales, The definition region of interannual to Interdecadal .Mega-ENSO includes the tropical Pacific and subtropical regions of the Pacific Ocean. Given that it has a broader space-time scale than traditional ENSO, the Mega-ENSO index may contain a richer and more complex gas than traditional ENSO. For example, mega ENSO is the main driving force of summer monsoon precipitation in the Northern Hemisphere, including the Indian summer precipitation ISRN, the East Asian summer monsoon precipitation EASR, etc. But this role is not reflected in traditional ENSO. Monsoon is very important to agricultural production, water utilization rate and food safety. Its interannual variability affects agricultural production to a large extent, distribution can have a serious impact on grain production, in turn, A threat to food security in India, with a rapidly growing population. In addition, ENSO and monsoon are two components of interaction in the climate system. Due to the phase-locked characteristics of ENSO, summer monsoon is usually in its development or attenuation period. Most of the studies focus on traditional ENSO, and very few focus on its stage of development. The purpose of using mega-ENSO index is to obtain more complete information about ENSO system. Since mega-ENSO is a rate of variability with a larger range than traditional ENSO, It will be important to explore whether ISR and atmospheric circulation respond to mega-ENSO and traditional ENSO and their different connections. This is one of the starting points of this study. This paper mainly compares the different relationships between typical mega-ENSO-ISR and atypical ENSO-ISR. El Nino development period in summer, In the typical La Nina development summer, the anomalous pattern of precipitation is almost linearly opposite. For the atypical ENSO, this "linear opposite" phenomenon disappears. In addition, there is a zonal anomalous wave train in the mid-latitude region. In the summer of a typical mega-ENSO development period, the local response is the tripole circulation pattern in the east-central Eurasia, which may be the cause of the corresponding precipitation anomaly in the Indian subcontinent. These characteristics are not obvious in the development period of atypical ENSO in summer. Using the 106-year operating results of CMIP5 9 models, HadGEM2-ES shows a good ability to simulate anomalous circulation patterns, but CanESM2 is poor. We also compare the relationship between typical mega-ENSO-EASR and atypical ENSO-EASR in the attenuation period. In the typical El Nino attenuation period, the precipitation tripole anomaly in East Asia is different from that in the typical La Nifla attenuation period. For atypical ENSO, this phenomenon disappears. In addition, in the summer of a typical mega-ENSO attenuation period, the local response of a zonal anomalous wave train in the mid-latitude region is a tripole circulation pattern in the east-central Eurasian continent. The main circulation patterns in summer during the attenuation period of atypical ENSO occur in the North Pacific Ocean. The results of CMIP5 9 models also show good simulation ability, but CanESM2 is poor, in addition, the main circulation patterns occur in the North Pacific Ocean during the attenuation period of atypical ENSO. For typical mega-ENSO-ISR, the difference in simulation ability of ENSO-EASR linkages may also be due to its ability to simulate typical mega-ENSO features.
【學(xué)位授予單位】：南京信息工程大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：P732
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本文編號(hào)：1582370