青藏高原与伊朗高原热力协同作用对夏季南亚高压与中国降水的影响

发布时间：2018-02-04 07:21

本文关键词： 青藏高原伊朗高原地表感热通量地表潜热通量南亚高压　出处：《中国气象科学研究院》2017年硕士论文　论文类型：学位论文

【摘要】：青藏高原是我国东部地区灾害性天气的“上游关键区”,伊朗高原热力作用对其邻近地区和下游区域的大气环流也有重要影响,是影响我国气候的众多因子中不可忽视的一部分。因此对两高原的热力协同作用进行研究,可以进一步认识造成我国气候异常的外强迫因子,有助于提高气候预测准确率进而减少洪涝等自然灾害带来的损失。本文综合利用再分析资料与台站观测资料,基于EOF分析、SVD分析、相关分析等统计方法,详细分析了春夏季青藏高原与伊朗高原地表热通量的时空分布特征和联系,以及春季两个高原地表感热异常对夏季南亚高压和中国降水的影响。主要结论如下:(1)青藏高原地表热通量的时空分布表现为:春、夏季地表感热量值西部大而东部小,地表潜热则相反,东部地区潜热大而西部地区潜热小;地表感热在春季最大且大于地表潜热,地表潜热在夏季最大且大于地表感热。在年际时间尺度上,春夏季青藏高原地表热通量异常的年际变化在东、西部是不一致的,高原西部地表感热与潜热有较强的负相关关系,而高原东部地表感热与潜热关系并不显著。青藏高原地表感热异常具有很强的持续性,当春季地表感热较强(弱)时,夏季高原地表感热同样较强(弱)。青藏高原东部与西部地表热通量的年代际变化有明显差异,春(夏)季青藏高原东部地表感热有显著的年代际减弱趋势,在1998(2001)年发生年代际转折,由正异常转为负异常;而青藏高原西部地表感热在春季有显著的增大趋势,在2003年发生年代际转折,由负异常转为正异常。青藏高原东部地表潜热仅在春季为显著减弱趋势,在2003年出现年代际转折,由正异常转为负异常;青藏高原西部地表潜热在春、夏季都有显著减弱趋势,年代际转折出现在21世纪初,由正异常转为负异常。(2)对于伊朗高原,春、夏季地表热通量的空间分布在整个区域较一致,地表感热在夏季最大,地表潜热在春季大、夏季小,但各季节地表感热都大于地表潜热。相对于青藏高原地表感热,伊朗高原地表感热在各月都更大。在年际时间尺度上,春、夏季伊朗高原各区域地表热通量异常的年际变化较一致;地表感热与潜热有很强的负相关关系;伊朗高原地表感热、潜热异常都具有持续性,当春季地表感热(潜热)通量较强(弱)时,夏季地表感热(潜热)通量同样较强(弱)。伊朗高原北部与南部地表热通量的年代际变化存在差异。其中,春、夏季伊朗高原北部地表感热(潜热)呈显著增加(减弱)趋势,在20世纪末发生了年代际转折,春、夏季北部地表感热(潜热)由负(正)异常转为正(负)异常。伊朗高原南部春、夏季热通量无显著变化趋势,但春季地表感热、潜热与夏季地表感热同样在20世纪末存在年代际转折,地表感热(潜热)由负(正)异常转为正(负)异常。(3)春、夏季两个高原地区地表热通量的关系主要表现为:就春季同期变化而言,伊朗高原地表感热与青藏高原西部地表感热具有同位相变化关系,与青藏高原东部地表感热具有反相变化关系,伊朗高原地表潜热与青藏高原东部地表潜热具有同位相变化关系;就非同期变化而言,春季伊朗高原地表感热与夏季青藏高原东部地表感热存在反相变化关系。(4)春季月份中,5月伊朗高原与青藏高原地表感热异常协同作用(两个高原地区感热异常反相变化)与6月南亚高压的关系最密切。当5月伊朗高原感热偏大(小)而青藏高原感热偏小(大)时,6月印度夏季风强(弱),印度北部的对流活动旺盛(衰弱),因此印度北部凝结潜热释放偏强(偏弱),南亚高压偏西北(东南)。(5)5月两高原地表感热异常协同作用只是引起南亚高压主体位置西北-东南方向摆动的触发机制,对南亚高压的影响只能持续到6月。7月南亚高压的西北-东南方向摆动是环流与降水带来的凝结潜热之间的正反馈过程导致的。6月南亚高压位置偏西北(东南),通过调节印度夏季风区与东亚夏季风区的凝结潜热造成7月南亚高压位置偏西北(东南),使7月印度夏季风和东亚夏季风偏强(弱)。(6)7月印度夏季风偏强(弱)造成印度北部降水偏多(偏少),东亚夏季风偏强(弱)造成中国长江中下游降水偏少(偏多),而这种降水配置又进一步使南亚高压位置偏西北(东南)。
[Abstract]:The Tibetan Plateau is the eastern region of China weather disasters "upstream key region, atmospheric circulation in Iran plateau region and the thermal effect on the downstream region also has an important influence, is an important part of many factors influence the climate in China. So the thermodynamic two plateau synergy research, can to further understand the cause of abnormal climate in China external forcing factors, help to improve the accuracy of climate prediction and reduce the losses caused by floods and other natural disasters. This paper uses analysis data and observation data analysis of SVD stations, EOF analysis, based on the statistical methods of correlation analysis, a detailed analysis of the temporal and spatial distribution characteristics and the the plateau in spring and summer and the surface heat flux of the Iran plateau, and in the spring of two plateau surface sensible heat anomaly of summer South Asian high and China precipitation. The main conclusions are as follows: (1) green The temporal and spatial distribution of Tibetan Plateau surface heat flux as follows: spring, summer surface calorific value western and Eastern small, surface latent heat in the eastern region and the western region of small latent heat latent heat; sensible heat and latent heat in the spring maximum is bigger than the surface, surface latent heat in summer and more than the maximum surface sensible heat on the interannual. On the scale of the spring and summer of Qinghai Tibet plateau surface heat flux anomalies interannual variation in the East, the west is not consistent, the western plateau surface sensible heat and latent heat has a strong negative correlation, while the eastern part of the plateau surface sensible heat and latent heat is not significant. The relationship between Tibetan Plateau sensible heat anomaly is persistent, when the spring surface sensible heat strong (weak) summer, the plateau surface sensible heat as strong (weak). There was significant difference between the interdecadal variation of the eastern Tibetan Plateau and the western surface heat flux, the spring season (summer) in the eastern Tibetan Plateau have significant surface sensible heat The interdecadal weakening trend, in 1998 (2001) years interdecadal, by positive anomalies in turn negative anomaly; while the western Qinghai Tibet plateau surface sensible heat in spring has a significant increasing trend, in 2003 the interdecadal turning from negative abnormal to positive anomalies in the eastern Tibetan Plateau. Only the surface latent heat in the spring as a significant weakening trend, interdecadal turning point in 2003, by the positive anomaly to negative anomaly; Western Tibetan Plateau surface latent heat in the spring and summer have a significant weakening trend, interdecadal transition appears at the beginning of twenty-first Century, the positive anomaly to negative anomalies. (2) for the Iran plateau, the spring, the surface heat flux in summer the spatial distribution in the whole region is consistent with the surface sensible heat in the summer, surface latent heat in the spring, summer is small, but the seasonal surface sensible heat is greater than the surface latent heat sensible heat. Compared to the Qinghai Tibet Plateau, Iran in the form of sensible heat in each month are more In the inter annual time scale, spring and summer interannual variation in Iran plateau regions of the surface heat flux anomalies are consistent; surface sensible heat and latent heat has a strong negative correlation; Iran plateau surface sensible heat, latent heat anomaly has a persistent, when spring surface sensible heat (latent heat flux) strong (weak) when in summer, the surface sensible heat (latent heat flux) equally strong (weak). The existence of Iran plateau north and south of the interdecadal variation of surface heat flux differences. Among them, the spring and summer in North Iran plateau surface sensible heat (latent heat) was significantly increased (decreased) trend, interdecadal shifts, at the end of twentieth Century spring. The northern summer surface sensible heat (latent heat) from negative (positive) anomaly to positive (negative) anomalies. The southern Iran plateau in spring, summer heat flux had no significant change, but the spring sensible heat, latent heat and sensible heat in summer also has decadal turning at the end of twentieth Century, the surface sensible heat (latent heat) A negative (positive) anomaly to positive (negative) anomalies. (3) the spring summer two plateau surface heat flux is mainly as follows: the spring period changes, Iran plateau and Western Tibetan Plateau sensible heat of surface sensible heat in phase change, phase change has relationship with the Tibetan Plateau the original Eastern Iran plateau surface sensible heat, latent heat and latent heat in the eastern Tibetan Plateau having phase change between non collocated; period change, spring Iran plateau sensible heat flux and surface sensible heat over the eastern Tibetan Plateau have inverse relationship. (4) the spring months in May, the Iran plateau and Qinghai Tibet plateau surface sensible heat anomaly synergy (two plateau phase change thermal anomaly) most closely with the June South Asia high relationship. In May when the Iran plateau sensible heat is larger (smaller) and the Qinghai Tibet Plateau sensible heat is small (large), the June India summer monsoon strong (weak), India The strong convective activity in the North (weak), the northern India latent heat release is stronger (weaker), South Asia high Northwest (southeast). (5) surface in May two plateau sensible heat anomaly synergy caused only Northwest - southeast of South Asia high body position swing the trigger mechanism of the South Asia high impact only last June.7 months to South Asia high Northwest - southeast direction swing between latent heat circulation and precipitation brought the positive feedback process leads to.6 months of South Asia high position Northwest (southeast), the latent heat regulation area of India summer monsoon region and East Asia summer wind in July caused the South Asia high position Northwest (southeast) so, the July India summer monsoon and the East Asian summer monsoon is strong (weak). (6) July India summer monsoon is stronger (weaker) resulting in more rainfall in northern India (small), the East Asian summer monsoon is strong (weak) caused by rainfall in the Yangtze River downstream of Chinese (partial Much more), and this precipitation allocation further makes the South Asian high pressure north-west (southeast).

【学位授予单位】：中国气象科学研究院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P461

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