共查询到16条相似文献,搜索用时 140 毫秒
1.
热带大气季节内振荡的几个基本问题 总被引:20,自引:5,他引:20
在一系列资料分析、数值模拟试验和理论研究的基础上,对热带大气季节内(30-60天)振荡的几个基本问题进行系统的综合讨论,包括热带大气季节内振荡的地域特征、空间尺度特征、水平传播特征、与中高纬度大气季节内振荡的联系、同E1Nino间的相互作用以及热带大气季节内振荡的动力学机制。通过讨论和分析,对热带大气季节内振荡得到一个更全面和更系统的认识。 相似文献
2.
热带大气季节内振荡的进一步分析 总被引:2,自引:1,他引:1
利用ECMWF的格点资料对热带大气季节内振荡作了进一步分析研究,表明热带大气季节内振荡既有Kelvin波型扰动,也有Rossby波型扰动;影响热带大气季节内振荡移动的主要因素有扰动波型和积云对流活动的异常;伴随ElNino事件的发生,热带大气季节内振荡的动能急剧减小,而准定常扰动动能急剧增大,既反映了热带大气季节内振荡对ElNino的激发作用,也说明了在ElNino期间热带大气季节内振荡偏弱的原因。 相似文献
3.
4.
5.
6.
El Ni?o影响热带大气季节内振荡的动力学研究 总被引:3,自引:0,他引:3
根据El Ni?o期间热带大气状态的异常特征,确定了在简单大气动力模式中描写海温异常的参数化方法。然后利用斜压半地转两层模式从动力学上分析研究了El Ni?o对热带大气低频波的影响。理论分析同有关热带大气季节内振荡的资料分析结果完全一致,El Ni?o事件使热带大气季节内振荡减弱。 相似文献
7.
中国热带大气季节内振荡研究进展 总被引:7,自引:1,他引:6
热带大气季节内振荡(包括MJO)是大气环流的重要系统,它的活动及异常既对其他系统有一定的作用,也对长期天气和短期气候有明显影响。因此,热带大气季节内振荡一直是大气科学的前沿研究课题之一。文中对近5—10年中国学者的有关研究工作及其进展做了简要回顾和综合,主要包括:(1)热带大气季节内振荡特别是MJO的动力学机制;(2)热带大气季节内振荡以及MJO的数值模拟问题,特别是大气非绝热加热廓线对模式模拟MJO的重要作用;(3)热带大气季节内振荡和MJO,特别是在赤道西太平洋地区,与ENSO的相互作用关系;(4)热带大气季节内振荡(包括MJO)及其流场形势对西太平洋台风活动的重要影响,即MJO对西北太平洋台风生成数的调制作用,以及热带大气季节内低频气旋性(LFC)和反气旋性(LFAC)流场对西太平洋台风路径的影响;(5)热带大气季节内振荡(包括MJO)的活动及异常对东亚和南亚夏季风建立、活动异常的影响,以及它们与中国降水异常的密切关系。 相似文献
8.
与中国东部天气气候相关的大气季节内振荡研究及业务应用 总被引:1,自引:0,他引:1
回顾了近年来国内外对大气季节内振荡(ISO)活动影响东亚地区,尤其是影响我国东部地区冬夏季降水变化的研究成果,重点阐述了夏季影响我国长江流域的ISO来源及影响路径,并对目前国际上基于热带大气季节内振荡活动开展的次季节-季节预测研究计划和业务应用以及我国热带大气季节内振荡的业务现状进行评述。 相似文献
9.
10.
11.
LI Chongyin LING Jian SONG Jie PAN Jing TIAN Hu CHEN Xiong 《Acta Meteorologica Sinica》2014,28(5):671-692
Tropical intraseasonal oscillation (including the Madden-Julian oscillation) is an important element of the atmospheric circulation system. The activities and anomalies of tropical intraseasonal oscillations affect weather and climate both inside and outside the tropical region. The study of these phenomena therefore represents one of the frontiers of atmospheric sciences. This review aims to synthesize and summarize studies of intraseasonal oscillation (ISO) by Chinese scientists within the last 5-10 years. We focus particularly on ISO's mechanisms, its numerical simulations (especially the impacts of diabatic heating profiles), relationships and interactions with ENSO (especially over the western Pacific), impacts on tropical cyclone genesis and tracks over the northwestern Pacific, and influences on the onset and activity of the South and East Asian monsoons (especially rainfall over China). Among these, focuses of ongoing research and unresolved issues related to ISO are also discussed. 相似文献
12.
大气季节内振荡对夏季西北太平洋热带气旋群发性的影响 总被引:13,自引:1,他引:12
利用中国气象局上海台风研究所整编的热带气旋最佳路径资料、 向外射出长波辐射 (OLR) 和NCEP/NCAR再分析风场资料, 研究了1991年夏季西北太平洋热带气旋的群发性特征及其与大气季节内振荡的关系。结果表明, 1991年6~9月西北太平洋地区的对流活动存在20~60天的准周期振荡, 该区域的热带气旋活动也具有这种频率的季节内变化, 即热带气旋的活动具有明显的群发性和周期性。进一步分析表明, 热带气旋易集中出现在大气季节内振荡的湿位相, 这是因为湿位相期间大气低层维持的较大尺度的低频气旋性环流为天气尺度的热带气旋的生成提供了有利的背景环流场。低频气旋中心东南侧的不稳定低空西风急流容易激发出一些小扰动, 低空的低频正涡度异常又有利于这些初始小扰动的增长, 同时, 热带气旋发生势 (genesis potential) 表现为正距平, 说明热带气旋发生发展的垂直风切变条件容易满足, 因而导致热带气旋的相继群发。 相似文献
13.
FURTHER STUDIES ON EVAPORATION-WIND FEEDBACK 总被引:1,自引:0,他引:1
李崇银 《热带气象学报(英文版)》1997,3(1):11-17
The results from simple dynamic studies on the evaporation-wind feedback show that the effect cannot change the nature of tropical atmospheric waves (by retarding the speed), so that the evaporation-wind feedback alone cannot be an exciting mechanism of intraseasonal oscillation in the tropical atmosphere. This is different from that of the wave-CISK mechanism. With combined effect of the cumulus convection heating and evaporation-wind feedback, the CISK-Kelvin waves and CISK-Rossby waves will develop unstably, explaining the dynamic mechanism of tropical intraseasonal oscillation in a more complete and reasonable way than the convection heating alone. Therefore, the evaporation-wind feedback is also important to the intraseasonal oscillation in the tropical atmosphere. 相似文献
14.
Intraseasonal Oscillation in the Tropical Indian Ocean 总被引:1,自引:1,他引:1
1. Introduction The intraseasonal oscillation (ISO or Madden- Julian Oscillation, MJO) in the tropical atmosphere has been studied extensively, including its existence, structure, evolution and propagation (Madden and Ju- lian, 1971; Murakami, et al., 198… 相似文献
15.
Comparison of the Structure and Evolution of Intraseasonal
Oscillations Before and After Onset of the Asian Summer Monsoon 下载免费PDF全文
High-resolution satellite-derived data and NCEP-NCAR reanalysis data are used to investigate intraseasonal oscillations (ISO) over the tropical Indian Ocean.A composite evolution of the ISO life cycle is constructed,including the initiation,development,and propagation of rainfall anomalies over the tropical Indian Ocean.The characteristics of ISO over the tropical Indian Ocean are profoundly different before and after the onset of the Indian summer monsoon.Positive precipitation anomalies before monsoon onset appear one phase earlier than those after monsoon onset.Before monsoon onset,precipitation anomalies associated with ISO first initiate in the western tropical Indian Ocean and then propagate eastward along the equator.After monsoon onset,convective anomalies propagate northward over the Indian summer monsoon region after an initial eastward propagation over the equatorial Indian Ocean.Surface wind convergence and air-sea interaction play critical roles in initiating each new cycle of ISO convection. 相似文献
16.
The impact of tropical intraseasonal oscillations on the precipitation of Guangdong in Junes and its physical mechanism are analyzed using 30-yr (1979 to 2008), 86-station observational daily precipitation of Guangdong and daily atmospheric data from NCEP-DOE Reanalysis. It is found that during the annually first rainy season (April to June), the modulating effect of the activity of intraseasonal oscillations propagating eastward along the equator (MJO) on the June precipitation in Guangdong is different from that in other months. The most indicative effect of MJO on positive (negative) anomalous precipitation over the whole or most of the province is phase 3 (phase 6) of strong MJO events in Junes. A Northwest Pacific subtropical high intensifies and extends westward during phase 3. Water vapor transporting along the edge of the subtropical high from Western Pacific enhances significantly the water vapor flux over Guangdong, resulting in the enhancement of the precipitation. The condition is reverse during phase 6. The mechanism for which the subtropical high intensifies and extends westward during phase 3 is related to the atmospheric response to the asymmetric heating over the eastern Indian Ocean. Analyses of two cases of sustained strong rainfall of Guangdong in June 2010 showed that both of them are closely linked with a MJO state which is both strong and in phase 3, besides the effect from a westerly trough. It is argued further that the MJO activity is indicative of strong rainfall of Guangdong in June. The results in the present work are helpful in developing strategies for forecasting severe rainfall in Guangdong and extending, combined with the outputs of dynamic forecast models, the period of forecasting validity. 相似文献