500hPa全球动能年际变率及1983和1987年两个厄尼诺年动能距平的差异

利用１９８０—１９８８年９年期间ＥＣＭＷＦ５００ｈＰａ全球风场资料，计算７个“纬度带”上三种基本动能模态，研究这些动能模态的各年异常情况。结果表明，１９８３年是这９年内动能唯一的正值异常年，而１９８７年和１９８５年动能基本上属于正常年，只有个别动能模态有异常。这说明，１９８０年代两个厄尼诺年的异常情况有很大的差异。动能模态与赤道东太平洋海温距平（ＳＳＴＡ）的后延相关表明，１９８３年事件的影响可以波及范围相当广泛甚至波及全球大气，而１９８７年事件所能影响的范围远比１９８３年事件要小。此外，还表明北半球副热带急流轴附近是对ＳＳＴＡ响应的敏感地区。     

关于阻塞形势演变过程中波数域能量的诊断分析

本文对北半球冬季维持时间较长的三次阻塞形势形成前的纬向平均西风变化以及阻塞过程中波数域动能及其转换进行了诊断分析。分析结果表明：在阻塞形势形成前，由于波流相互作用，使得平均流减弱，并且波流相互作用在太平洋地区和大西洋地区有不同的特点；分析结果还表明：阻塞形势维持期间，由于波波相互作用，行星波异常增幅；而在崩溃期间，也主要通过波波相互作用使得行星波动能减少。     

El Nio与La Nia期间大气加热场的特征及其对大气环流的影响

本文采用欧洲中心７层网格点逐月平均全球资料和同期美国ＫＷＢＣ的太平洋海温资料分析了１９８２年１月～１９８３年１２月ＥｌＮｉｎｏ期间和１９８８年１月￣１９８９年１２月ＬａＮｉｎａ期间大气加热场的特征。结果表明，海表温度异常时，海面向上输送的感热、潜热通量变化并不大，有时甚至出现和海温距平变化相反的趋势，而另一方面，各辐射量和凝结加热量变化却很重要。进一步本文又分别以多年平均的１２月、ＥｌＮｉｎｏ及ＬａＮｉｎａ强盛时的１９８２年１２月和１９８８年１２月的实测海温和实测大气资料为初值作了数值模拟，模拟的大气状况与真实大气状况一致。根据资料分析和数值模拟的结果，本文认为作大尺度中长期天气预报及研究海气相互作用时应充分考虑辐射收支和凝结加热量的变化。     

1982/1983年El Ni?o演变的动力学结构分析

目前，ENSO循环动力学机制仍存在争议。本文在研制热带太平洋线性分层模式的基础上，利用ECMWF 1981～1984年的风场分析资料，进一步模拟分析了El Ni?o的海洋动力学结构和机制。结果较真实地揭示了海洋温跃层扰动的演变。指出海洋表层与次表层间卷挟作用激发新的Kelvin模和Rossby模，它们与经典的动量交换激发的Kelvin模和Rossby模相叠加是温跃层扰动的基本动力学机制。东边界反射Rossby模对温跃层扰动和海洋气候状态恢复具有重要作用。上述动力学模态是El Ni?o循环时滞振荡子机制的本     

The Influence of Tibetan Plateau on the Interannual Variability of Asian Monsoon

ＴｈｅＩｎｆｌｕｅｎｃｅｏｆＴｉｂｅｔａｎＰｌａｔｅａｕｏｎｔｈｅＩｎｔｅｒａｎｎｕａｌＶａｒｉａｂｉｌｉｔｙｏｆＡｓｉａｎＭｏｎｓｏｏｎ①ＷｕＡｉｍｉｎｇ（吴爱明）ａｎｄＮｉＹｕｎｑｉ（倪允琪）ＤｅｐａｒｔｍｅｎｔｏｆＡｔｍｏｓｐｈｅｒｉｃＳｃｉｅ...     

中国沿岸海平面变化原因的探讨

对中国沿岸的月均海平面的变化原因进行了较为细致的分析，讨论了温、压、降水对中国沿岸海平面的影响。得出渤海是我国月均海平面变化最大的海区；黄海月均海面的变化仅次于渤海；东海更次；南海最小。出现极值的时间自北向南依次滞后。静压效应的影响也是自北而南逐渐变小。月均海面中除包含了８～９年及１０多年的长周期变化外，１４．０和１８．０个月左右的周期对海平面有明显的影响，３年的周期不是一种沿岸传播的波动周期。ＥｌＮｉｎｏ对中国沿岸海平面起补偿平衡作用。黑潮的增强使中国沿岸海平面均有明显的抬升。     

Evolutions of flow field and heat exchange on equatorial Pacific surface in El Nino-La Nina cycle

Abstract-In this paper, the monthly averages and deviations of temperature, pressure, tonal wind, specific humidity, cloud rover and the components of heat budget have been remputed on the equatorial (5°S-3°N) Pacific surface (EPS) based on the 2^*×2^* grid data of CORDS from 1950 to 1987 and the evolutions of tt0ese elements have been provided. Two feedback mechanisms of El Nino-La Nina cycle which include the dynamic, thermal and hydrological processes in the coupled air-sea system are verified. During El Nino, the pressure gradient and trade wind decreased on the EPS, the sensible and latent heat exchanges enlarged on the central-eastern EPS, the water vapor and cloud cover rose in the atmo sphere, the net longwave radiation and incident solar radiation decreased and the net gain (loss) of the heat reduced (increased) on the central and eastern EPS:During La Nina the circumstances were opposite     

赤道太平洋温度、流场距平EOF分析及与厄尔尼诺的关系

利用EOF分析方法,讨论了最近20a赤道太平洋次表层温度、纬向流距平与厄尔尼诺的关系.结果表明:赤道太平洋海温距平EOF分析第一、二主分量占总量的近80%,其中第一主分量类似于厄尔尼诺模态,第二主分量类似于暖池模态;后一模态存在着突变和渐变两种过程,其中由冷位相变暖位相过程为渐变过程,而暖位相变冷位相过程为突变过程.厄尔尼诺事件是赤道西太平洋暖池突变过程的结果.赤道太平洋纬向流距平EOF的第二主分量代表赤道西太平洋潜流和东太平洋南赤道流的变化,这个模态存在着半年左右的振荡和与厄尔尼诺同位相的年际振荡两种频率.另外,它还存在明显的年代际变化.赤道西太平洋潜流和东太平洋南赤道流减弱是产生厄尔尼诺的必要条件.统计回归分析表明,赤道太平洋海温距平和纬向流距平EOF的第二特征向量的时间系数对厄尔尼诺和拉尼娜均有一定的预报意义.     

Morphodynamics of a high discharge tropical delta, San Juan River, Pacific coast of Colombia

The San Juan River has one of the most extensive and best developed deltas on the Pacific coast of South America, measuring 800 km². The river drainage basin measures 16?465 km² and is located in one of the areas with the highest precipitation in the western hemisphere. The annual rainfall varies from 7000 to 11?000 mm, and as a result the San Juan River has the highest water discharge (2550 m³ s⁻¹), sediment load (16×10⁶ t yr⁻¹), and basin-wide sediment yield (1150 t km⁻² yr⁻¹) on the west coast of South America. The San Juan delta growth began approximately 5000 years BP. The structure of the delta is determined by the interactions between fluvial deposition and the effect of 1.7-m significant swells, mostly from the SW, and strong tidal currents. Analysis of delta progradation indicates that during 1848-1992 the morphology of the delta was characterized by beach ridge accretion, spit growth, narrowing of inlets, and a general advance of the delta shoreline. During the past decade processes such as rapid erosion of the delta shore, narrowing of barrier islands, and breaching of a new inlet, are the result of a long-term relative sea-level rise of 2.6 mm yr⁻¹ due to tectonically induced subsidence coupled with a eustatic rise of sea-level. The delta also experiences strong oceanographic manifestations associated with the El Niño-La Niña cycle, causing regional sea-level elevation of 20-30 cm during El Niño years. Recent coastal subsidence in the delta is evidenced by: (1) increased occurrence of non-storm washover events; (2) increased erosion of barrier islands with average loss of 11 m yr⁻¹ during 1993-1997; and (3) a relative sea-level rise of 3.4 mm yr⁻¹ during 1991-1999. The morphology and recent evolution of the San Juan delta are unique when compared to other deltas of South America because of the singular combination of extreme climatic, geologic, and oceanographic conditions under which the delta has formed and the absence of human-induced impact in the drainage basin.