【作者】 李勇；

【导师】 何金海； 陆日宇；

【作者基本信息】 南京信息工程大学 ， 气象学， 2006， 硕士

【摘要】 本文采用美国NCEP/NCAR月平均再分析资料、英国东安吉利亚大学(University of East Anglia)气候研究室的北半球月海平面气压资料、NOAA Extended Reconstructed SST资料以及国家气象中心月平均的全国160站温度和降水资料,从大尺度环流的角度分析了太平洋西部遥相关型(WP)异常及其与我国冬季气候的关系,揭示出了WP型与赤道中东太平洋海温以及北极涛动、东亚高空急流等环流系统之间的可能联系。此外,还综合讨论了冬季若干气候因子对我国大陆气温的影响。主要结论归纳如下: 北半球冬季WP遥相关型有明显的年际变化和年代际变化特征。该遥相关型在对流层不同层次高度场上均存在,具有相当正压结构。高低WP指数年大尺度环流场具有明显差异。高指数年东亚地区经向气压梯度偏大,中纬度西风偏强,环流呈纬向型,对应海平面气压场上西伯利亚高压偏弱,东亚冬季风偏弱。在这样的环流背景下,我国东部沿海、华南及西南部分地区温度偏高,相应东部地区的降水也偏多。低指数年上述情况则恰好相反。 WP遥相关型与赤道中东太平洋海温不仅具有同时相关关系,而且海温超前WP型5个月时这种关系就很显著了。WP型可能是联系赤道中东太平洋海温与东亚冬季风的一个桥梁。赤道中东太平洋海温通过影响WP型进而影响东亚冬季风。进一步的研究也表明,WP型相对于海温表现出一定的独立性,它的存在并不依赖于海温,而是更多地由大气内部动力过程决定,海温异常仅仅对WP型的强弱有一定影响作用。 WP遥相关型还与北极涛动、东亚高空急流等环流系统有一定关系。北极涛动也可能通过影响WP遥相关型异常进而影响东亚冬季风。此外,高(低)WP指数年,东亚高空急流偏弱(强)。表明WP不仅受到低纬度热带海洋的影响,中高纬系统可能对其也有显著作用。同时,不仅对流层下层系统对其有影响,对流层上层系统也可能对其产生影响。 WP遥相关型、东亚高空急流及西伯利亚高压在年际尺度上对我国大陆气温有显著影响。WP型的影响主要存在于我国东部从东北南部至广东沿海一带大陆边缘区,高空急流主要影响我国中部地区,而西伯利亚高压的影响范围则大的多,几乎涵盖了除黄河长江上游部分地区外的整个中国。但在年代际尺度上,北极涛动与ENSO的影响则是主要的。从空间分布来看,ENSO与温度的关联区位于35°N以北的整个北方及长江中下游地区。与之相比,北极涛动的范围更大,除长江上游沿江地区外的其它地区均有关联。更多还原

【Abstract】 The NCEP/NCAR global reanalysis monthly data、 the NOAA Extended Reconstructed monthly SST from the Climate Diagnostics Center, The northern hemisphere monthly sea level pressure data set provided by the University of East Anglia and the monthly 160-station temperature and precipitation data set of the Chinese mainland provided by the National Climate Center are used in the paper. We present a study on the anomaly feature of western Pacific teleconnection pattern (WP) and their relation with the climate of China in winter from the point view of lager-scale circulation. The relationships between WP pattern and Arctic Oscillation (AO)、Eastern Asian Jet (EAJ) were also analyzed. In addition, we discussed synthetically the effects of several climate factors on winter temperature over China. The main results show as following:In boreal winter, WP pattern have obvious the interannual and interdecadal variation characters. It can be observed in the whole troposphere and there is an equivalent barotropic structure in vertical direction. The differences of the circulation are extraordinarily notable between strong and weak WP pattern. In the higher WP index years (strong WP pattern) , the longitudinal pressure gradient enlarges and the middle latitude western wind is strengthened, the circulation is zonal pattern in East Asian . In accordance, the Siberian High (SB) and the East Asian winter monsoon (EAWM) are weak than normal. An inverse circulation sense was observed in the lower WP index years (weak WP pattern). In addition, the WP index positively correlates to the winter temperature and precipitation in China. In temperature aspect, significant correlations are concentrated in the region which begins from the eastern coast, goes to the south, then turns to the southwestern region, while only eastern region of China is significant to precipitation.The WP pattern is intimately related to the sea surface temperature (SST) in the tropical central eastern Pacific not only in winter but also the preceding summer season. From summer-autumn seasons the SST starts to affect the WP pattern and persists to the end of winter. The SST can affect strength of the EAWM by influencing WP pattern, WP pattern acts as a bridge between the EAWM and SST in the tropical central eastern Pacific. Further studies shows that WP is independent with SST in a certain degree. WP pattern is not entirely determined bySST and interior dynamic force is also important in the atmosphere.There are also some relationship between the WP pattern and ACK EAJ in winter. The AO can also affect strength of the EAWM by influencing WP pattern. The EAJ is weaker than normal when WP index is higher. An inverse sense was found in the lower WP index years. This indicates that WP pattern is related to not only low-latitude systems but also high-latitude systems, and to system not only in low troposphere but also in high troposphere.The western Pacific teleconnection pattern and SB have significant influence on winter temperature in China on the interannual timescale. WP pattern mainly influences the east of marginal areas from the south of the northeast China to coastal cities in Guangdong province. EAJ influences the central of China. The region associated with SB covers almost the entire China except for the upper reach of Yangtze and Huanghe River, which is larger than that associated with the WP pattern. However, the temperature is strongly affected by AO and ENSO on the interdecadal timescale. The area under the impact of ENSO includes North China and the middle and lower reaches of Yangtze River. Compared to ENSO, AO affects larger areas including the entire mainland except for some regions on the upper reach of Yangtze River.更多还原