台湾附近地形对台风影响的数值模拟

利用ＴＣＭ－９０资料分析并用数值方法成功地模拟了９０１７号台风经过台湾时发生复杂变化的过程，包括环流场副中心和高度场副中心形成及与其主中心的合并过程，环流中心合并时路径跳跃过程，台湾西侧低压中心异常北移过程，台湾海峡低层急流变化过程以及上下层高度中心与环流中心明显偏离的现象，并详细分析了模拟中每隔３小时的演变过程，给出了台风经过台湾前后的结构及详细的路径变化，这种详细的演变图像不可能从间隔６小时的     

ENHANCED REGIONAL NUMERICAL PREDICTION SYSTEM AND ITS PERFORMANCE

During the "8th Five-Year Plan"(1991～1995), a new operational mesoscale numerical predictionsystem is developed, which is called the "Regional Enhanced Numerical Prediction System". The system possesses higher resolution(45 km grid sise in horizontal, 10 layers in vertital), as well as fullphysical processes, and can be run operationally in the Guangzhou Regional Meteorological Centre(GRMC). A plenty of experiments indicate its better performance in predicting various weather systemsaffecting the south of China, especially the typhoon and heavy rain in the "early floods stage"(annuallyspeaking). Verification of the prediction of all typhoon cases affecting the region in 1993～1995 indicatethat rainfall prediction scores of the system are obviously higher than those of the LAFS in the NationalMeteorological Centre, and track prediction error is no larger than those of NWPs in main world centressuch as the National Hurrieane Center of NOAA and the JMA. The aim of the paper is to give a generalized introduction and analysis to the system and its performance.     

925hPa资料对高度场分析和预报的影响

通过连续１５天的平行业务数据预报试验，详细地分析了９２５ｈＰａ资料的应用对高度场分析和预报的影响。结果表明，９２５ｈＰａ资料的加入对印度洋西北部及马来西亚至菲律宾以南热带地区的分析影响较大，对其余地区影响较小。总的来说对形势场分析影响不很大，且对低层的影响大于中高层。同时，可以明显地减小从Ｐ面分析场到模式σ面的垂直插值误差。此外，对２４小时预报场的影响小于对初始场的影响，同时对模式积分的平稳性和预     

华南区域短期气候模式产品时间过滤方案及实例分析

用尺度分离方法分析了短期气候预测序列中所包含的各种尺度的过程,建立了不同尺度变化的过滤、提取方法;分析讨论了各种过滤序列所具有的气候意义和重要程度;用模拟实例分析了所提出和使用的尺度分离方法的有效性及模式的性能     

区域增强数值预报系统中的客观分析

主要介绍了广州区域气象中心新建立的区域增强数值预报系统的资料处理方案。该分析方案的实施包含三个步骤，第一步以Ｔ６３模式的分析（或预报）作为初估场，进行多变量的最优统计插值（ＯＩ），将不同类型的观测资料插值到模式网格点上，同时分析增量满足一些简单的动力约束关系；第二步是对分析要素作单变量的逐步订证；第三步则是对分析场进一步做变分调整。通过这三个步骤，不仅可以使最终的分析场保留大尺度气象特征，而且可以     

NUMERICAL SIMULATION STUDY OF THE EFFECTS OF TERRAIN AROUND TAIWAN ON TYPHOON DOT(1990)

With the use of analyzed TCM-90 data,Typhoon Dot(1990)and complex evolutions are successfullyreproduced in numerical sboulation as it travels over the island of Taiwan. The simulation includes theformation of secondary highs in both circulation and geopotential fields, trajectory jumps during mergence with main centers, anomalous northward movement of a low center west of Taiwan, evolutionalprocess of a low-level jet over the Taiwan Straits and significant deviations of circulation center fromgeopotentia1 center between upper and lower levels. By examining ev0lutions of 3-h interval simulatedresults, detailed processes of changes in structure and track before and after Dot's passage of Taiwanis given, whose evolutional images are otherwise impossible with conventionai observations at intervalsof 6 h. A number of control experboents are conducted in the end of the work for understanding causesand mechanisms behind various properties.     

中尺度模式中p-面与σ-面扩散差异的数值分析

对常用的四阶线性水平扩散的两种方案进行了量纲分析和简化，并用有地形中尺度模式对两种方案做了详细的对比数值试验和分析。一种方案是在σ－面上计算水平扩散（以下简称为方案Ａ），另一种方案是通过坐标变换使扩散在准ｐ－面上进行（以下称为方案Ｂ）。试验结果表明，在地形平缓区域，两种方案的预报差异较小，而在陡峭地形附近，则预报差异很大，两方案的２４小时降水预报差异可达５０ｍｍ以上。原因是方案Ａ中出现了温度和湿度     

THE PROPAGATION CHARACTERISTICS OF INTERANNUAL LOW-FREQUENCY OSCILLATIONS IN THE TROPICAL AIR-SEA SYSTEM

The time series of sea surface temperature(SST), sea level pressure (SLP), zonal wind (U) and total cloudiness (CA), for the period of 1950-1979, over a 8°×8° grid-point latitudinal belt between 32° S and 32°N are made from COADS (Comprehensive Ocean-Atmosphere Data Set). The time harmonic analysis and power spectra analysis show that there exist quasi-biennial oscillation (QBO), three and half years oscillation (SO), five and half years oscillation (FYO) and eleven years oscillation (EYO) in these time series. The main propagation characteristics of these interannual low-frequency oscillations are as follows:(1) The variance analysis of SST shows that there is an active region of QBO and SO (with maximum variance), coming from the southwestern part of the subtropical Pacific, stretching eastward up to the west coast of South America, and then northward to the eastern equatorial Pacific. The QBO and SO disturbances of SST follow the same route and cause the anomaly of SST (El Nino and period of col