热带大气季节内振荡的异常与1997年El Nio 事件的发生     

李崇银  龙振夏 《大气科学》2001,(5)

利用美国NCEP资料分析热带大气季节内振荡（ISO）与ENSO的关系，揭示了1997年El Ni o事件的发生，与赤道中西太平洋地区大气 ISO在 1996年冬到 1997年春期间的异常增强有重要关系。而且该地区 ISO的异常增强并不主要由赤道印度洋地区移来，主要表现为ISO在印度尼西亚上空被激发增强和东传。印度尼西亚地区ISO的被激发，则是由于东亚冬季风强异常在该地区引起的强对流活动的结果。  相似文献   

INVESTIGATION ON GEOSTROPHIC ADJUSTMENT,FRONTOGENESIS AND OSCILLATIONS^*          下载免费PDF全文

PAN Yinong  WU Rongsheng 《Acta Meteorologica Sinica》2001,15(3):346-355

Geostrophic adjustment and frontogenesis are examined by means of the 2-D ARPS model.The simulation shows that.without the large-scale forcing,both the frontogenesis and frontolysisare observed during the geostrophic adjustment process and the intensity of the front oscillates inthe case of no discontinuity.The convergence (divergence) induced by the secondary circulation isthe most important factor for frontogenesis (frontolysis) at the top and bottom boundaries.Theamplitude and period of oscillation are dependent on the initial atmospheric stratification and theCoriolis frequency,and they are related to the inertio-gravity wave.  相似文献   

中国降水准两年周期变化   总被引：22，自引：1，他引：22  

朱乾根  智协飞 《南京气象学院学报》1991,14(3):261-268

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EFFECT OF ARCTIC ICE COVER ON THE MONTHLY TEMPERATURE AND PRECIPITATION IN CHINA          下载免费PDF全文

Chen Yinsheng  Chen Longxun 《Acta Meteorologica Sinica》1992,6(3):275-286

Filtering technique, extended empirical orthogonal function (EEOF), spectrum distribution function and correla-tion analysis have been employed to study the relationship between arctic ice cover (AIC) and monthly mean tempera-ture and precipitation in China. The function of power spectrum density shows that not only a semi-annual and an an-nual oscillation but also a quasi-biennial oscillation can be found in AIC area index series, especially in June, Septemberand November. During the period of analysis, it can also be found that there exists a good correlation between the ElNino events and the AIC area index. An analysis on the EEOF of AIC and the temperature over China exhibits somesignificant temporal-spatial patterns and a better time-lag interrelationship between them. The results from the correla-tion analysis indicate that the variation of AIC area has a significant influence on the temperature and precipitation insubsequent months over China. In addition, it experiences a quasi-biennial low-frequency oscillation and displays tocertain extent some features of propagation.  相似文献   

1982—1983年冬季亚澳地区低频振荡的分布与联系     

王坚红  何金海 《南京气象学院学报》1992,15(1):39-46

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夏季风场40—50天振荡的全球分布及波动特征   总被引：1，自引：0，他引：1  

徐建军  何金海 《南京气象学院学报》1992,15(3):358-367

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上扬子台地西缘峨眉地区三叠纪高频层序与海平面振荡研究   总被引：2，自引：1，他引：2  

赵玉光  许效松  刘宝珺 《沉积与特提斯地质》1996,16(1):1-18

通过精细露头层序地层学的研究，将三叠纪标定了二级层序２个，三级层序９个。提出并厘定了层序旋回的等级系列：一级（２００—４００Ｍａ），二级（１０—１００Ｍａ），三级（１—１０Ｍａ），四级（０．１—０．２Ｍａ），五级（０．２—０．０５Ｍａ）和六级（±０．０２Ｍａ）层序旋回。将三叠纪盆地划分为被动边缘（Ｔ１＋２）和前陆盆地（Ｔ３）阶段。进一步标定了古构造沉降对有效容纳空间及层序形成的贡献。提出并规范了高频层序的内涵本质及其划分方案。建立并标定了不同物质背景之下的高频层序四种鉴定类型：三角洲河口坝或滨岸旋回序列型；波痕指数垂向有序变化型；厚层灰岩或白云岩与薄层灰岩或白云岩有序叠置偶合型和砂屑灰岩与砂、泥岩层偶型。高频层序行为堆叠样式及其所携带的信息可深刻地揭示三级层序的内部构架，提高地层对比精度。为建立高分辨率层序地层学和定量编制全球海平面变化曲线奠定了基础。  相似文献   

夏季中低纬低频波的活动特征和驱动机制     

王建德  唐东升 《南京气象学院学报》1993,16(4):413-417

利用１９８４年夏季ＥＣＭＷＦ／ＷＭＯ资料分析了低频涡度系统和低频辐散环流系统，讨论了两者之间的相互作用。结果表明西太平洋和南印度洋上的低频涡旋具有对流性天气系统的三维环流特征，低频速度势场在上述两区域表现为最大的辐合辐散强度和最宽广的辐合辐散区，低频散度波的能量频散激发和驱使印度洋至西太平洋区域内辐散环流呈现明显的准４０天振荡。  相似文献   

The Propagation of Disturbances Excited by Low-Frequency Oscillations in the Tropics     

Lu Peisheng 《大气科学进展》1993,10(3):287-295

The propagation of disturbances excited by low-frequency oscillations in the tropics is investigated by applying the theory of wave packet dynamics. For simplicity, a linearized barotropic model is adopted and the zonal circulation is taken as basic current. Suppose that the disturbances or waves are superimposed on jet-like westerly basic cur-rent and excited by the forcing in the tropics. We have (1) only the eastward propagating (m>0, n>0 and σ>0) low-frequency disturbances and the stationary (σ = 0) waves can propagate into the middle and high latitudes in the Northern Hemisphere; the others, such as the westward propagating low-frequency wave (m>0, n<0, σ<0) and the high-frequency waves, are restricted only in the vicinity of source region; (2) a stationary wave (σ = 0) reaches a given latitude even more quickly than some low-frequency ones (σ>0) due to the fact that the group velocity of stationary wave is larger; (3) there is a whole wave train excited by the forcing in the tropics and extended into the middle and high latitudes, if the amplitude of the source is independent on time, especially, the low-frequency wave (σ > 0) is of travelling type propagating along the ray; (4) if the source lasts only for an interval of time, namely, its amplitude also has the character of low-frequency oscillation, the excited wave train is not always a whole one, but is restricted in the vicinity of source region in the beginning, extended from the source region to the middle and high latitudes in its saturated stage, after that it gradually becomes weaker and weaker and is detectable only in some area at high latitude, and eventually disappears. Undoubtedly, case (4) is closer to the reality, even though case (3) gives a more impressive wavy pattern.  相似文献   

青藏高原感热加热对7月份大气环流和亚洲夏季风影响的数值试验   总被引：4，自引：1，他引：4       下载免费PDF全文

胡江林  朱乾根 《热带气象学报》1993,9(1):78-84

根据低纬地区地表温度高、蒸发及降水量大、辐合上升运动剧烈等特点,本文构造了一个正压模式的方程组,提示出影响低纬大气波动的一个重要因素——海表温度SST。研究指出:(1)当SST<25℃时,含蒸发风反馈机制的Rossby波向西传播,当SST>25℃时.含蒸发风反馈机制的Rossby波向东传播。(2)SST的数值越高,空气越潮湿,含蒸发风反馈机制的Rossby波传播速度就越小。当SST超过29℃时,会形成周期为30天的低频振荡。  相似文献