【作者】 巩远发；

【导师】 何金海；

【作者基本信息】 南京信息工程大学 ， 气象学， 2008， 博士

【摘要】 利用NCEP/NCAR再分析资料、OLR资料、国家气象信息中心的降水等资料,通过资料分析和动力诊断等方法,围绕着亚洲季风区的大气热源（简记为<Q₁>）及其低频振荡的主题,对青藏高原和东亚地区<Q₁>的气候特征、低频振荡及其对副热带高压和长江流域夏季天气气候异常（干旱或洪涝）的影响和作用机制等问题进行了较为系统的研究。主要结论包括:（1）在亚洲季风区,气候平均<Q₁>的30-70天振荡（ISO）和准双周振荡（BWO）都可以分辨出印度（南亚）季风系统和东亚季风系统的显著差异。东亚季风系统中,最突出的特征是<Q₁>的ISO和BWO都表现为非常清楚的南北两个强振荡带,北边一条与副热带季风相联系,位于25°N～30°N附近的中国东部长江流域到日本南部的副热带洋面上;南边一条与热带季风相联系,位于中国南海到菲律宾东部的热带洋面上。印度季风系统中,阿拉伯海、青藏高原西南侧及孟加拉湾是<Q₁>ISO最强的地区,但BWO的强度（范围）相对较弱（小）。（2）在弱（强）东亚夏季风年,青藏高原东部夏季的<Q₁>变化、高原东部降水中断（活跃）变化、副热带高压的南北进退变化三者之间有很好的联系。在弱季风年,都是BWO显著;而强季风年,则是ISO明显。从相关分析也可以看到,三者之间存在这样一个链接关系:高原东部<Q₁>变化→高原降水变化→副热带高压变化。（3）对典型的长江流域特大洪涝年和气候平均态,在西北太平洋中部副热带地区（150°E、30°N附近）,<Q₁>ISO扰动在4月底到5月初突然增强:5～8月期间,这个强的ISO信号沿30°N向西传播到110°E～120°E附近的长江流域,同时也有自南海向北传播到江淮地区的ISO扰动:6月初到7月初是自东向西传播与自南向北传播的<Q₁>ISO正位相交汇于我国长江流域的时间:交汇区的南北位置和出现时间变化与长江流域夏季“梅雨”带出现的位置和时间有关系。但对于长江流域严重干旱年,西北太平洋中部副热带地区则没有明显的<Q₁>ISO扰动的强信号发生并向西传播。因此,西北太平洋中部副热带地区的<Q₁>ISO扰动的强信号激发及其向西传播可能是江淮“梅雨”触发的另外一个机制。（4）对典型的长江流域特大洪涝年,伴随着<Q₁>ISO的变化,夏季5～8月,在西太平洋副热带地区和热带赤道附近不断有ISO（反）气旋环流系统生成,并向西、向北移动到我国东部及沿海地区。到长江流域的持续性暴雨时期,850hPa上形成一个强大的自南海北部到日本南部洋面的ISO反气旋环流系统,我国江南地区到日本岛南部形成一条强盛ISO低空急流带,长江流域到朝鲜半岛形成一个ISO辐合带;200hPa上长江流域是一个ISO反气旋环流系统的中心,南海北部到台湾南部洋面是ISO气旋系统辐合带。与ISO环流系统配合,长江流域有非常利于降水的ISO环流条件和水汽条件稳定维持。更多还原

【Abstract】 Based on the daily datasets from the National Center for Environment Prediction and National Center for Atmospheric Research（NCEP/NCAR）reanalysis（versionⅠ）, Outgoing Longwave Radiation（OLR）data and the daily rainfall from the Chinese National Meteorological Information Centre,surrounding on the themes of the atmospheric heat sources（<Q₁>）and their low frequency oscillation,the features of climatology,low frequency oscillation of <Q₁> over the Tibetan Plateau and Eastern Asia and their mechanism and relations to the subtropical high and the drought-flood of eastern China are clearly investigated by the synoptic-dynamical diagnosis.Main results are as follows:（1）The significant differences between the East Asian Monsoon System and South Asian（Indian）Monsoon System can be distinguished by the 30-70 days Oscillation（Intraseansonal Oscillation,ISO）and Bi-weekly Oscillation（BWO）of climatic <Q₁>.In the East Asian Monsoon area,there are two intensity oscillation belts of the <Q₁> ISO and BWO,the north oscillation belt is located to the subtropical latitude between the Yangtze River basin and the Pacific area of Southern Japan which is relation to the East Asian subtropical monsoon,the south oscillation belt is located to the tropical area between the South China Sea and the Ocean of the eastern Phillips which is relation to the tropical monsoon.In the South Asian（Indian） Monsoon area,the <Q₁> ISO is the most intensity oscillation over the Arabian Sea, side of the southwestern Tibetan Plateau and Bay of Bengal,but the intensity and area of the <Q₁> BWO are the weak and little.（2）In summer of the weak or strong East Asian monsoon,the <Q₁> over the Eastern Tibetan Plateau,the active or break rainfall of the Tibetan Plateau and the northward or southward shift of the subtropical high ridge have the same low frequency oscillation features.Their BWO are all very significance in summer of the weak monsoon,but the ISO are all more important in summer of the strong monsoon. Based on the correlation analysis,the <Q₁> variety over the Eastern Tibetan Plateau lead to the rainfall active or break on the Eastern Plateau,and then affected the northward or southward shift of the subtropical high.（3）For the typical great flood years and climate rainfall of the Yangtze River basin,the intensity of <Q₁> and OLR ISO is abruptly increasing from the ending of April to the beginning of May over the subtropical area of the northwest Pacific central section（near by 150°E,30°N）.The strong ISO signal propagate westward to the Yangtze River basin of eastern China along 30°N during May and August,at one time,the ISO signal of the South China Sea propagate northward to the Yangtze and Huaihe River basin of China.The positive <Q₁> ISO（or the negative OLR-ISO）are converged over the Yangtze and Huaihe River basin in June and July,the location and time of the convergent area are maybe relations to the area and time of the "Meiyu" rainfall belt in summer.But the strong <Q₁> ISO signal is not obviously and westward propagation over the subtropical area of the northwest Pacific for the drought year of the Yangtze River basin,therefore it maybe be an another mechanism of the "Meiyu" rainfall that the strong <Q₁> ISO signal arises and propagate westward over the subtropical area of the northwest Pacific.（4）For the typical great flood years of the Yangtze River basin,the ISO anticyclone and cyclone system are continue making and move westward and northward to the eastern China and the coastwise western Pacific by the change of <Q₁> ISO during May and August.In the continuous strong rainfall period,on the 850hPa,a powerful ISO anticyclone system is formed from the South China Sea to the Pacific of south Japan,at one time,a strong ISO low-level jet stream belt is make from the China Jiangnan district to southern Japan Island and it is the convergence area from the Yangtze River basin to the Korea Island.On the 200hPa,it is an ISO anticyclone system centre over the Yangtze River basin and there is the ISO cyclone system convergence belt from the South China Sea to the ocean of eastern Taiwan. Owing to the ISO circulation system on the 850hPa and 200hPa,there are very steady ISO circulation conditions and moisture conditions which is beneficial to rainfall of the Yangtze River basin.更多还原