排序方式： 共有47条查询结果，搜索用时 718 毫秒
1.
利用9层15波全球大气环流谱模式研究了太平洋海温异常对南海西南季风建立早晚的影响作用.结果表明:西-中太平洋海温异常数值试验结果最能反映出南海西南季风爆发早、晚年4～5月份大气环流的差异特征.数值试验结果显示:西太平洋海温正(负)异常可导致西太平洋副高减弱(加强);中太平洋海温正(负)异常主要使得中太平洋上空的洋中槽减弱(加深);东太平洋海温正(负)异常可造成东太平洋赤道两侧高层环流产生反气旋性(气旋性)变化,孟加拉湾-南海-西太平洋热带地区出现东风(西风)异常,西太副高加强(减弱).可见西太平洋海温异常和东太平洋海温异常都可以对副高强弱变化产生明显影响,从而对南海西南季风建立早晚产生影响,只不过西太平洋海温异常的影响作用更为显著.西太平洋正(负)海温异常与中太平洋负(正)海温异常经常是同时出现的,其激发出的与向东传的Kelvin波和向西传的行星波相联系的环流异常为南海季风建立早(晚)提供有利的条件,因而这一海温分布型是影响南海西南季风建立早晚的重要影响因子. 相似文献
2.
According to the basic characteristics of the activities of summer monsoon in the South China Sea,Standardized index,Is,has been designed that integrates a dynamic factor(southwesterly component) and a thermodynamic factor(OLR) for the indication of summer monsoon in the South China Sea,With the index determined for individual months of June,July and August and the entire summertime from 1975 to 1999,specific months and years are indicated that are either strong or weak in monsoon intensity,The variation is studied for the patterns and Is‘s relationship is revealed with the onset of summer monsoon and the precipitation in Guang-dong province and China.The results show that there are quasi-10 and quasi-3-4 year cycles in the interannual variation of the monsooon over the past 25 years.When it has an early(late)onset,the summer monsoon is usually strong (weak),In the strong(weak)monsoon,years,precipitation tends to be more(less)in the first raining season of the year but normal or less(normal)in the second,in the province,but it would be more(less) in northeastern China and most parts of the northern china and south of the lower reaches of the Changjiang River and less(more)in the middle and lower reaches of the river,western part of northern China and western China. 相似文献
3.
4.
The work has made a statistic study of the variations of extremely severe cold winter months in
the south of China and general circulation and external forcing factors in preceding periods. The result shows
that from the current month to the preceding March the subtropical high in the west Pacific is persistently weak
or located more to the east and south. When the summer monsoon is weak in East Asia in the year before, the
winter monsoon will be strong in the current year in which the extremely severe cold month occurs. The Asian
polar vortex expands in the preceding July, August and September and the current winter. The Tibetan Plateau
has fewer days of snow cover in the November and December before the cold month occurs. There is less snow
in the Tibetan Plateau in the preceding winter / spring of each extremely severe cold month. There are more
polar ice in the polar Region for the 11 months before the current February, especially the previous March
through August, and in Region in January ~ November before the current cold month of December but less
ice in Region in March ~ August. 相似文献
5.
6.
南海西南季风爆发日期及其影响因子 总被引：40，自引：6，他引：34
利用1950～1999年NCEP全球格点日平均资料,在总结南海西南季风爆发前后850 hPa大气环流特征的基础上,提出了一个较为客观的确定南海西南季风爆发日期的大气环流方法.在与1980～1991年其他多种指标确定的爆发日期比较后,作者认为该大气环流方法所确定的爆发日期基本合理,并给出了1950～1999年各年南海西南季风爆发的日期.通过合成对比分析和相关分析发现,前期热带太平洋地区海温异常分布是影响南海西南季风爆发早晚的重要因素.菲律宾以东洋面海温偏高,赤道太平洋中部偏东地区海温偏低,可以使低层西太平洋副高减弱、高层中东太平洋洋中槽加深,印度洋热带地区偏西风偏强,印度洋-太平洋热带地区Walker环流偏强,为热带对流在孟加拉湾-南海地区发展提供了有利的环境.在孟加拉湾南部偏西气流的作用下,南海地区对流活动较为容易发展起来,低层较弱的西太平洋副热带高压也容易较早地撤出南海上空,使得南海西南季风较早爆发.反之亦然. 相似文献
7.
The NCEP reanalyzed data, OLR and SST observations are used to study the onset time and the multi-time scales features of the South China Sea (SCS) summer monsoon in 1998 and its interaction with the sea surface temperature and the effect on the precipitation in Guangdong province. It is found that the 1998 SCS summer monsoon set in on May 17 (in the fourth pentad of the month). The year witnesses a weak monsoon with the OLR oscillating at cycles of about 1 month and the Southwest Monsoon of about 1/2 month. The mon-soon over the Bay of Bengal and the cross-equatorial current near 105°are two driving forces for low-frequency variations of the SCS monsoon. The weak activity in the year was resulted from positive anomalies of SST in the equatorial eastern Pacific in early spring and subsequent formation of positive anomalies of SST in the SCS through the Arabian Sea. 相似文献
8.
Impact of the Thermal State of the Tropical Western Pacific on Onset Date and Process of the South China Sea Summer Monsoon 总被引：8，自引：0，他引：8
Since the early or late onset of the South China Sea summer monsoon （SCSM） has a large impact on summer monsoon rainfall in East Asia, the mechanism and process of early or late onset of the SCSM are an worthy issue to study. In this paper, the results analyzed by using the observed data show that the onset date and process of the SCSM are closely associated with the thermal state of the tropical western Pacific in spring. When the tropical western Pacific is in a warming state in spring, the western Pacific subtropical high shifts eastward, and twin cyclones are early caused over the Bay of Bengal and Sumatra before the SCSM onset. In this case, the cyclonic circulation located over the Bay of Bengal can be early intensified and become into a strong trough. Thus, the westerly flow and convective activity can be intensified over Sumatra, the Indo-China Peninsula and the South China Sea （SCS） in mid-May. This leads to early onset of the SCSM. In contrast, when the tropical western Pacific is in a cooling state, the western Pacific subtropical high anomalously shifts westward, the twin cyclones located over the equatorial eastern Indian Ocean and Sumatra are weakened, and the twin anomaly anticyclones appear over these regions from late April to mid-May. Thus, the westerly flow and convective activity cannot be early intensified over the Indo-China Peninsula and the SCS. Only when the western Pacific subtropical high moves eastward, the weak trough located over the Bay of Bengal can be intensified and become into a strong trough, the strong southwesterly wind and convective activity can be intensified over the Indo-China Peninsula and the SCS in late May. Thus, this leads to late onset of the SCSM. Moreover, in this paper, the influencing mechanism of the thermal state of the tropical western Pacific on the SCSM onset is discussed further from the Walker circulation anomalies in the different thermal states of the tropical western Pacific. 相似文献
9.
冬季广东气温变化与500hPa环流的关系及预测研究 总被引：3，自引：2，他引：1
１ 资 料 本研究中以１月份代表广东的冬季,主要使用了广东省３６个气象站１９６０～１９９６年１月平均气温和北半球５°×１０°５００ｈＰａ平均位势高度资料。分析发现,广东省各地１月份平均气温的变化具有较强的一致性,３６个站月平均气温的平均可以很好地反映出广东省月平均气温的变化。因此,以下的讨论中所使用的１月平均气温为３６站月平均气温的平均。２ 与同期５００ｈＰａ位势高度的关系 从１月份广东平均气温与同期５００ｈＰａ位势高度的相关系数分布中可以看出,在我国东部地区和西太平洋上存在一个显著的正相关… 相似文献
10.
本文采用所谓“以测站扫描格点”的逐步订正方案分析500毫巴热带流场。预备场是由有限元法提供的。得到了满意的分析结果。计算量减少到原来的二十七分之一,大大缩短了计算时间。此方案对业务工作有实用价值。 相似文献