对流层中层动能的全球性季节过渡与季节性急变

本文利用１９８０—１９８８年ＥＣＭＷＦ全球资料，计算了５００ｈＰａ各纬度带上的纬向平均动能（Ｋｚ）、涡动动能（ＫＥ）及波数域动能（Ｋｎ，ｎ＝１，２，３，…，１０）。以此考察了南、北半球动能季节过渡的差异，并用Ｔ检验方法讨论了南、北半球以及全球各动能模态的季节性急变现象。现在工作单位：     

全球500kPa角动量与EP通量的季节变化

利用ＥＣＭＷＦ提供的９ａ（１９８Ｏ－１９８８）资料，从定性和定量角度分析５００ｈＰａ全球东西风带的角动量和ＥＰ通量的季节过渡。结果发现：不仅角动量存在明显的季节性急变，而且反映波活动的ＥＰ通量也存在相应的季节性急变。另外，季节性急变的发生时间在东西风带亦有所不同。     

海南热带气旋的球谐分析及其预报

利用球坐标系的正交系数族展开北半球５００ｈＰａ高度场，再用其展开系数与海南热带气旋长期预报六要素求相关，建立同期相关模型，并利用上年１－１２月５００ｈＰａ球谐系数及同年１－４月５００ｈＰａ球谐系数分别建立了海南省热带气旋长期预报六要素的预报模型。经使用检验，效果较好。     

亚洲季风区大气热源和水汽汇的季节内变化Ⅱ. 水汽汇的季节内变化

研究了北半球初秋（９月）５００ｈＰａ孟加拉湾（１５°Ｎ，８５°Ｅ）与日本海（４０°Ｎ，１３０°Ｅ）的遥相关结构、年际变化及其与热带东风急流、厄尔尼诺事件、中国降水的关系．指出，当孟加拉湾５００ｈＰａ高度上升时，日本海高度下降。这时通常是低南方涛动指数或发生厄尔尼诺、并且在１００ｈＰａ上热带东风入口区为西风距平。这些特征造成中国东部初秋降水偏少。利用这些结果可以清楚地诊断近４０年中发生的厄尔尼诺事件。     

中国西北夏季降水的EOF分析及其与500hPa高度场的关系

本利用我国１１０°Ｅ以西的１４０个台站７－９月月降水量及５００ｈＰａ１０°×５°网格点资料（１９６０－１９９０年），与７－９月月降水量分别进行ＥＯＦ分解，并与５００ｈＰａ高度场进行了对比。结果发现：７－９月月降水量第一特征向量在青藏高原东北侧有一高值中心，该中心与有关学计算的信噪比高值中心和准３年周期显的区域一致（均指降水量）；７－８月月降水量第一特征向量与５００ｈＰａ高度场在２０°－４０°     

1980年和1981年旱涝异常的热力及环流特征

应用５００ｈＰａ非绝热热流量诊断资料和５００ｈＰａ、１００ｈＰａ高度资料，分析了１９８０、１９８１年北半球大所热力场及大气环流特征。分析结果表明：这两年盛夏，北半球非热热流量距平存在明显差异，在欧亚大陆一带表现出相反发布，前期６月也具有类似特征，相应北半球大气环流存在显著不同。     

与厄尔尼诺有关的北半球100hPa大气环流异常

研究了北半球１００ｈＰａ冬季遥相关现象，指出，北半球冬季１００ｈＰａ存在ＰＮＡ流型，它的波列与５００ｈＰａ流型很接近，当厄尔尼诺发展到盛期（冬季）时，１００ｈＰａ出现强ＰＮＡ型，这种对应关系比５００ｈＰａ好些，此外，还研究了厄尔尼发生、发展各阶段的１００ｈＰａ低纬风场以及１００ｈＰａ春，夏，秋，冬四季平均环流异常特征，发现在厄尔尼诺发生年春季，１００ｈＰａ高度比反厄尔尼诺年大范围偏低，发生前的冬季     

100hPa南亚高压变化与陕南秋季（9—10月）降水的关系

分析１９７０￣１９９２年９￣１０月１００ｈＰａ历史资料和陕南地区平均面雨量资料。结果表明，５００ｈＰａ形势及台风活动对１００ｈＰａ南亚高压变化具有较大影响，且能造成陕南地区秋季（９￣１０月）降水。     

数值预报对热带气旋移动路径的预报能力的检验

作者利用１９９５年６－１０月影响南中国海的１０个热带气旋实况资料以及５００ｈＰａ天气图，对日本地面２４小时数值预报和ＥＣＭＷＦ５００ｈＰａ为数值预报产品对热带气旋移动路径的预报能力进行检验和分析，结果表明；１．日本的２４小时地面数值预报对热带气旋的路径趋势有一定的预报能力，它对路径稳定的热带气旋预报能力较好，对热带气旋的突变转折预报能力较差。２．ＥＣＭＷＦ５００ｈＰａ数值预报对热带气旋的移动路长有     

1995年北半球主要环流特征及其影响

１９９５年北半球大气环流的主要特征是：５００ｈＰａ西太平洋副热带高压异常偏强，初夏脊线位置偏南，盛夏偏北；亚洲西风带，春季经向环流发展，初夏东亚阻塞形势稳定，盛夏纬向环流盛行；５００ｈＰａ青藏高原位势高度夏半年偏高，冬半年偏低；北半球１００ｈＰａ位势高度低纬度持续偏高，中高纬度持续偏低，南亚高压偏强；１９９４年开始的厄尔尼诺事件于１９９５年３月结束。     

On the seasonal transition and the interannual variability in global kinetic energy at 500 hPa,accompanied with anomalies of energy during the 1982/83 ENSO

Utilizing the material of monthly means of the three primary kinetic energy modes over the whole globe at 500 hPa during the nine years of 1980-1988, both the rapid seasonal changes and the interannual variability in the general circulation in terms of the energy modes have been investigated, with special attention paid to the unusual year 1983. Two main results are obtained. One, there are remarkable seasonal rapid changes over the Northern Hemisphere, oc-curring generally in April and October. The other, among the nine years of 1980-1988, 1983 is the only one with unusual energy modes and remarkably abnormal seasonal changes.     

全球不同纬度带平均有效位能的季节急变

利用1980～1988年ECMWF的资料，计算了对流层500 hPa、300 hPa和平流层100 hPa逐日和月平均的纬向平均有效位能（PZ），分析其季节过渡，比较不同纬度带的季节性急变。结果表明，在4月和10月附近，各纬度带上均可出现PZ的急变。而且用逐日资料还可分析出6月急变。在北半球对流层高层（100 hPa）PZ的季节性急变不如低层（500 hPa）明显，而在南半球PZ的季节性急变与北半球相反，高层比低层明显。     

Nonlinear kinetic energy interactions and their contributions to the growth and decay of atmospheric waves in the lower troposphere during summer monsoon, 1979

Summary Lower tropospheric (1000–500) hPa kinetic energy (KE), temporal variations of KE and nonlinear KE transfer of rotational and divergent flows and energy conversion between them, partitioning further into stationary and transient components in the Fourier spectral domain and the mechanism for the evolution of significant transient waves for the month July 1979 in the latitudinal belt 10° S–30° N are studied.Divergent zonal and eddy KE show their maxima at the lowest level 1000 hPa. Lower tropospheric monsoon motion provides a non-divergent level close to 850 hPa. The daily flow patterns bear little resemblence to the climatology over tropics at 500 hPa. Although the transient mode of synoptic scale waves is stronger than that of planetary scale waves they are comparable. Analysis of energetics over global tropics can get signature of transient activities embedded in the large scale system. Summer momentum flux in the lower troposphere is essentially associated with stationary planetary and transient synoptic scale waves. Waves 1, 3 and 6 are the most preferred transient waves. Divergent to rotational KE conversion is the most dominating mechanism for the maintenance of planetary and synoptic scale waves. All categories of waves contribute towards the maintenance of zonal flows. The primary source of energy for transient synoptic scale waves is the transient divergent rotational KE transfer whereas the interaction between zonal stationary and transient wave is likely to be secondary source. Transient KE and all transient interactions, stationary KE and all stationary interactions are found to be strongest at 500 hPa and 850 hPa respectively. Growth and decay of transient waves 1 and 3 are mainly controlled by divergent-rotational KE conversions whereas those of transient wave 6 are controlled by KE transfer due to zonal-wave interaction.With 13 Figures     

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。     

春夏季节过渡期间北半球500百帕能量变化的波谱分析和研究

本文利用1972-1982年5月初-7月底春夏季节过渡期间北半球500百帕高度资料计算有关能量谱、角动量输送谱和扰动动能向平均动能转换率谱,分析了大气环流由春到夏季节过渡期间能量谱变化特征及过渡前后特征差异,并揭示了它们与初夏中期主要天气过程-梅雨天气过程的关系。结果表明由春到夏季节过渡前后,对流层中层扰动动能谱和大气波能密度均有显著变化,大气波能密度值有个急剧减弱过程,经向扰动动能集中的波数由超长波向长波转移,55、45、35°N角动量输送平均辐散也有明显转折,这些是春夏二种不同流型在能量学上的基本差异点。对流层中层扰动动能向平均动能转换率谱在季节过渡前后也有显著不同:过渡前高纬强于中纬;而过渡后中纬转换明显增强,并大大超过高纬。大气环流由春到夏的季节过渡,一般由一次或二次长波急剧发展来完成。在大型环流转变上对应为一次副热带高压明显北跳加强及西风带迅速北撒减弱,在天气表现形式上江淮流域对应为梅雨这种大型天气过程的出现。      

CHARACTERISTICS OF ATMOSPHERIC HEATING AND ATMOSPHERIC CIRCULATION DURING ACTIVE PERIOD OF 500 hPa HIGH OVER THE TIBETAN PLATEAU IN SUMMER*

In correspondence with the establishment of the "upper high and lower high" pressure pattern due to the activities of 500 hPa high over the Tibetan Plateau in summer,a series of changes of the East Asia atmospheric circulation will take place.In this paper,the distributions of divergence and vertical velocity of 500 hPa high,the evolutions of atmospheric heat source,the variations of vorticity and zonal wind at 100 hPa level and vertical meridional cell over the Tibetan Plateau etc.are statistically analyzed.Thus,we can see that the ascending motion and the convective heating over the Tibetan Plateau,the South Asia high and the westerly jet on the north of the Plateau at 100 hPa level are weakned.The northern branch and the southern branch of the easterly jet on the south of the Plateau merge into a single whole and situate on the south of the former northern branch.In the meantime,thermodynamic land-sea discrepancy in South Asia and the convective heating over the Bay of Bengal is enhanced.It will play an important role in the maintenance of the easterly jet and the South Asia monsoon.     

北半球500hPa 3—5年周期的初步研究

本文用带通时间滤波器，对北半球500hPa高度距平（从1951年1月—1986年12月共432个连续月）的每个格点的时间序列进行滤波计算，初步结果如下:1．北半球500 hPa普遍存在3—5年周期，该周期的相对方差都在30%以上。35°N以南相对方差可达50%以上，在太平洋、大西洋、欧亚低纬地区最大相对方差高于70%。2．3—5年周期的水平结构要比Wallace的遥相关型更具有波列结构，通过波列的射线路径可以把能量从低纬度频散到高纬度。3．从分析1982/1983 El Nino年个例可以看到，赤道东太平洋海水异常增暖对大气的影响，除了一般公认的通过PNA型影响北美外，可能还存在另一条路径。     

南半球500hPa月平均场谱物理量的气候特征

本文利用南半球500hPa多年（1972年5月至1987年12月）逐月高度场资料，在地转近似条件下，计算了500hPa高度场的各谱物理量，包括月平均环流场、纬向动能谱、经向动能谱、扰动角动量输送以及扰动动能向平均动能转换率。分析了它们的气候特征，发现谱物理量前3波的分布基本上决定了其总体分布，优势域的位置和强度随季节的变化较显著。     

Characteristics of Zonal Propagation of Atmospheric Kinetic Energy at Equatorial Region in Asia

Based on the daily NCEP/NCAR reanalysis dataset from 1980 to 1997, the zonal propagations of 850 hPa kinetic energy (KE) and meridional wind (v) at equatorial region are examined respectively. Results show that the strongest center of KE in the tropical Asian monsoon region is located at 75°-90°E, with the secondary over the Somalia low-level jet channel, i.e., about 50°E. East to 90°E, disturbances of both KE and v observed are mainly coming from the western Pacific Ocean and propagating westward to the Bay of Bengal (BOB) passing through the South China Sea. But the propagation directions of both KE and v are rather disorderly between the BOB and the Somalia jet channel. Therefore, the East Asian summer monsoon and the Indian summer monsoon are different in the propagating features of the disturbances of KE and v. Above facts indicate that East Asian monsoon system exists undoubtedly even at the equatorial region, and quite distinct from the Indian monsoon system, it is mainly affected by the disturbances coming from the tropical western Pacific rather than from the Indian monsoon region. The boundary of the two monsoon systems is around 95°-100°E, which is more westward than the counterpart as proposed in earlier studies by 5-10 degrees in longitude.     

1979年7月热带地区的动能平衡

应用欧洲中期预报中心的FGGEⅢ-b个客观分析资料计算了1979年7月热带大气的动能平衡。热带环流系统的动能主要集中在定常涡旋部分。对流层下层,105°E和150°E为两半球间瞬变涡旋的通道。对流层上层,瞬变涡旋的通道和洋中槽相联系,位于150°E和30°W附近。 索马里急流是对流层下层制造动能的主要环流系统。对流层上层,南亚东风急流入口区制造动能,出口区破坏动能,其动能收支与中纬度西风急流相似。 非洲-阿拉伯海季风区和孟加拉湾—南海季风区的动能平衡很不相同。动能的垂直输送可能在季风环流中很重要。