1901-2007年澳门地面气温变化的分析

 利用澳门的气温观测资料, 分析了澳门1901-2007年地面气温变化的基本特征。结果表明：近107 a的升温率为0.066℃/10a, 明显低于全球平均升温率。季节平均气温的年代际变化有明显的季节差异，最大的增暖发生在春季和冬季，夏季的增暖最小；冬、夏季的变化分别有明显的时间尺度约为60 a和30 a的振动。年平均最高气温的升温率仅为最低气温的一半左右。最高气温的年代际变化呈缓慢的气候波动现象，20世纪80年代中期以后的升幅与历史上的增暖大致相当；最低气温近20多年来的增暖趋势可能是其长期（变暖）趋势的延续。年平均日较差整体来说是趋于减少的，但近30 a却趋于增加。     

南海台风Vongfong(2002)登陆前后内核结构和近海加强原因的数值模拟研究

利用6 km细网格区域的显式模拟结果分析了Vongfong(2002)的内核结构;对Vongfong近海加强的动力学机制进行了研究.结果表明:(1) 轴对称性结构中,Vongfong最大风速半径(RMW)在强盛期随高度递减.Vongfong在近海时,低层最强的流入在其移行的前方,而流出区在其后方.这些特征与大西洋飓风和西太平洋台风相反.(2) 动力场和热力场都有明显的不对称结构.在强盛期,对流西北强、东南弱;强对流云带与最大风速区的位置一致.在加强期,低层西冷东暖、中高层西暖东冷;到强盛期,低层和中高层都有明显的暖心结构.(3) 中纬度中上层冷低压系统和台风的相互作用是Vongfong近海加强的重要原因.①由于冷低压系统外围的冷空气从西北侧进入台风的中层,低层有暖湿空气配合,使得位势不稳定能量增加,对流发展.②因为冷低压中心的下沉气流正是二级环流的下沉支,冷低压南移填塞,台风近海加强.两个方面最终通过CISK(第二类条件不稳定)机制来实现.     

西太平洋副热带高压强度和位置的气候特征

利用45年西太平洋副热带高压5个特征指数的月平均资料,对副高强度和位置变化的气候特征进行了诊断研究。结果表明,副高的强度在一年中出现两次峰值,第一次出现的在6月,第二次在9月。在45年里,副高强度有明显加强,融高位置有南落西移的趋势。副高强度存在3-4年、10-13年的振荡周期,10-13年的周期振荡在1950、1960、1970年代占主要地位,3-4年的周期振动在1980、1990年代占主要地位。副高在1978年附近发生气候突变,副高强度由负距平为主转为距平为主,而脊线位置正好相反。     

广东"97.7"暴雨的成因分析

1997年7月1～11日广东出现连续11天暴雨.暴雨过程的特点是:持续时间长,降水量大,范围广.据7月1日08时至12日08时统计,降水量>200mm的县(区)有48个,降水中心出现在英德(表1).     

一次华南暴雨过程的数值模拟及结果分析

利用非静力平衡的中尺度模式（ＭＭ５）对１９９４年５月初华南地区的暴雨过程进行模拟和分析,结果表明：（１）ＭＭ５相当准确的模拟出此次暴雨过程以及有关的中尺度系统的发生发展过程。（２）在弱的天气尺度背景条件下,边界层的中尺度辐合对暴雨的产生起了触发作用。暴雨强度一般随对流层上下部的辐散差值的增大而增大,最大的降水强度对最大的辐散差值的滞后时间不超过一小时。（３）降水的潜热加热作用对此次暖区暴雨的发展和     

凝结加热和地表通量对华南中尺度对流系统(MCS)发生发展的影响

通过有无凝结加热和地表通量影响的数值模拟对比研究，分析了非绝热过程对一次华南暴雨MCS发生发展过程的影响。结果表明：（1）凝结加热对MCS的降水影响很大，在MCS发展的各个时期，如不考虑凝结加热，MCS的降水强度很快减弱，无法继续发展。（2）凝结加热在MCS涡旋的形成期最为重要，在涡旋形成之后，影响相对减弱。（3）凝结加热通过对MCS发展过程的影响从而也影响了MCS环境场中尺度低空急流、高层辐散等中尺度结构特征的形成。（4）地表感热、潜热通量等边界层非绝热过程对MCS的形成也有重要影响；在暴雨MCS发生前期，地表非绝热过程造成气压下降，导致华南南部来自海洋的偏南风加大，辐合加强，从而使低层的湿度增大，气层变得更加不稳定，有利于对流的启动。     

广东省持续性暴雨的气候特征

分析了1952-2002年广东省持续性暴雨的气候特征,结果表明:地形对持续性暴雨的分布有重要影响,持续性暴雨的中心主要分布在沿海地区,粤中地区是次多发区.持续性暴雨中心主要在沿山体南侧分布,即迎风向的山前和迎风坡,前汛期主要以沿海的恩平、阳江和斗门为中心;后汛期主要以海丰、南澳为中心.全省各站都以持续2 d的暴雨为主,持续性暴雨在前汛期发生的次数比后汛期多,最多的月份是6月.全省全年及前后汛期持续性暴雨次数的年代际变化相似;但从年际变化看,前汛期与全年发生持续性暴雨次数呈正相关关系,而后汛期与之则呈现一定的反相关关系.持续性暴雨有20~25 a的长周期变化和2~4 a的短周期振荡.     

THE CLIMATIC CHARACTERISTICS OF SUMMER MONSOON ONSET OVER THE SOUTH CHINA SEA Ⅰ40—YEAR AVERAGE

By using 40-year NCEP reanalysis daily data91958-1997),we have analyzed the climatic characteristics of summer monsoon onset in the South China Sea(1050°E-120°E,5°N-20°N,to be simplified as SCS in the text followed) pentad y pentad(5 days),According to our new definition,in the monsoon area of the SCS two of the following conditions should be satistied:1)At 850hPa,the southwest winds should be greater than 2m/s.2)At 850 hPa.θse should e greater than 335°K.The new definition means that the summermonsoon is the southwest winds high temperature and high moisture.The onset of the SCS summer monsoon is defined to start when one half of the SCS area(105°E-120°E,5°N-20°N)is controlled by the summer monsoon.The analyzed results revealed the following:1) The summer monsoon in the SCS starts to build up abruptly in the 4th pentad in May.2) The summer monsoon onset in the SCS is resulted from the development and intensification of southwesterly monsoon in the Bay of Bengal.3) The onset of the summer monsoon and establishment of the summer monsoon rainfall season in the SCS occur simultaneously.4) During the summer monsoon onset in the SCS,troughs deepen and widen quickly in the lower troposphere of the India:the subtropical high in the Western pacific moves eastward off the SCS in the middle troposphere:the easterly advances northward over the SCS in the upper troposphere.     

CLIMATIC CHARACTERISTICS OF THE ONSET OF SOUTH CHINA SEASUMMER MONSOONⅡ.INTER—DECADAL VARIATION

By using the 40-year NCEP(1958-1997) grid point reanalysis meteorological data.we analyzed the inter-decadal variation on the climatic characteristics of the onset of South China Sea summer monsoon.The results are as follows.(1) There was great difference on the onset date of the SCS summer monsoon between the first two decades and the last two decades,It was late on the 6^th pentad of May for the first two decades and was on the 4^th and 5^th pentad of May for the next two decades.(2)Except for the third decade(1978-1987),the establishment of the monsoon rainfall was one to two pentads earlier than the onset of the summer monsoon in all other three decades.(3) The onset of the SCS monsoon is the result of the abrupt development and eastward advancement of the southwesterly monsoon over the Bay of Bengal.The four-decade analysis shows that there were abrupt development of the southwesterly monsoon over the Bay of Bengal between the 3rd and 4th pentad of May,but there was great difference between its ewastward ovement and its onset intensity.These may have important effect to the earlier or later onset of the SCS summer monsoon.(4) During the onset of the SCS summer monsoon.there were great difference in the upper and lower circulation feature between the first two and the next two decades.At the lower troposphere of the first two decades.The Indian-Burma trough was stronger and the center of the subtropical high was located more eastward.At the upper troposphere.the northward movement of the center of subtropical high was large and located more northward after it landed on the lndo-China Peninsula.After comparison.we can see that the circulation feature of the last two decades was favorable to the establishment and development of the SCS summer monsoon.     

THE CLIMATIC CHARACTERISTICS OF SUMMER MONSOON ONSET OVER THE SOUTH CHINA SEA I.40-YEAR AVERAGE

By using 40-year NCEP reanalysis daily data (1958-1997), we have analyzed the climatic characteristics of summer monsoon onset in the South China Sea (105°E ~ 120°E, 5°N ~ 20°N, to be simplified as SCS in the text followed) pentad by pentad (5 days). According to our new definition, in the monsoon area of the SCS two of the following conditions should be satisfied: 1) At 850hPa, the southwest winds should be greater than 2m/s. 2) At 850 hPa, θ_se should be greater than 335°K. The new definition means that the summer monsoon is the southwest winds with high temperature and high moisture. The onset of the SCS summer monsoon is defined to start when one half of the SCS area (105°E ~ 120°E,5°N ~ 20°N) is controlled by the summer monsoon. The analyzed results revealed the following: 1) The summer monsoon in the SCS starts to build up abruptly in the 4th pentad in May. 2) The summer monsoon onset in the SCS is resulted from the development and intensification of southwesterly monsoon in the Bay of Bengal. 3) The onset of the summer monsoon and establishment of the summer monsoon rainfall season in the SCS occur simultaneously. 4) During the summer monsoon onset in the SCS, troughs deepen and widen quickly in the lower troposphere of the India; the subtropical high in the Western Pacific moves eastward off the SCS in the middle troposphere; the easterly advances northward over the SCS in the upper troposphere.