共查询到20条相似文献，搜索用时 31 毫秒
1.
In this paper, four problems are discussed: (1) the monsoon circulation over southern Asia; (2) the seasonal variation of the general circulation of the atmosphere; (3) the influence of the monsoon on the rainfall in southwestern China; and (4) the source region of water vapor for the rainfall in the Changjiang valley. 相似文献
2.
3.
东亚夏季风与中国夏季降水年际异常的分型研究 总被引：10，自引：0，他引：10
以海陆气压差定义的夏季风强度指数为依据,讨论了东亚夏季风年际异常与中国夏季降水的关系,发现东亚夏季风强时,中国夏季降水可能多也可能少,但以少雨为主,季风弱时,中国降水也是或多或少,但以多雨为主,依此可以将季风与降水的异常关系分成强季风强降水（Ａ）,强季风弱降水（Ｂ）,弱季风强降水（Ｃ）,弱季风弱降水（Ｄ）四种关系,其中（Ａ）型和（Ｄ）型,（Ｂ）型和（Ｃ）型的降水呈反相似性分布,主要特殊性反映在东北 相似文献
4.
东亚夏季风的变化与中国降水 总被引：13，自引：1，他引：12
本文分析了1951—1980年东亚夏季风的强弱变化及其与我国降水分布的关系,发现夏季风强弱不同的时期,我国降水分布有明显差异。同时研究表明,随季风强弱的变化,相应的行星尺度环流亦发生明显改变。最后对夏季风强弱变化的可能原因进行了讨论. 相似文献
5.
THE EAST ASIAN SUBTROPICAL SUMMER MONSOON INDEX AND ITS RELATION WITH THE CLIMATE ANOMALIES IN CHINA
A new East Asian subtropical summer monsoon circulation index is defined, where the barotropic and baroclinic components of circulation are included. Results show that this index can well indicate the interannual variability of summer precipitation and temperature anomalies in China. A strong monsoon is characterized by more rainfall in the Yellow River basin and northern China, less rainfall in the Yangtze River basin, and more rainfall in south and southeast China, in association with higher temperature in most areas of China. Furthermore, comparison is made between the index proposed in this paper and other monsoon indexes in representing climate anomalies in China. 相似文献
6.
冬季风异常年份的环流特征及其与华南前汛期降水的关系 总被引：3，自引：0，他引：3
本文分析了1963—1982年资料,研究了冬季风异常年份的环流特征及其与华南初夏降水的关系。结果表明:冬季风强年,500百帕西太平洋副高偏弱,亚洲西风环流弱,东亚槽南伸,200百帕115°E西风急流强而偏北。冬季风弱年的环流特征与此相反。强冬季风年后期环流演变特点,中高纬度环流逐渐向夏季型过渡,而副热带环流则变化强烈。弱冬季风年后期中高纬度环流在2月下旬至3月上旬有一个反复的过程,副热带环流则是逐步增强北上的。强冬季风年初夏500百帕西太平洋副高较正常年偏强,位置偏北,西脊点偏东,100百帕南亚高压偏西,华南及珠江三角洲前汛期降水偏少。弱冬季风年初夏环流特点与此相反,华南及珠江三角洲前汛期降水偏多。 相似文献
7.
Liang Pingde 《Acta Meteorologica Sinica》1989,3(4):482-489
The analyses have been made of the summer precipitation data over Indian and North China during1891—1983.The statistic results show that the climatic characteristics of the Indian summer monsoon rainfallare similar to summer rainfall in North China,and a steady and significant positive correlation exists be-tween them.The circulation systems associated with the Indian monsoon and the rainfall in North China in summerhave also been discussed.It is found that there are same predictors in April to be used for the forecast ofNorth China rainfall and Indian monsoon. 相似文献
8.
东亚夏季风降水年代际变异模态及其与太平洋年代际振荡的关系 总被引：3，自引：0，他引：3
利用全球陆地月平均降水资料、英国气象局哈德莱中心的月平均海表温度距平(SSTA)资料及NCEP/NCAR再分析大气环流资料,探讨东亚夏季风降水年代际变率及其与太平洋年代际振荡(PDO)的联系。研究指出:东亚夏季风降水年代际变异模态以及PDO均在1976年前后呈现显著的年代际转折,并且东亚夏季风降水与PDO在年代际尺度上具有较好的相关关系。PDO能够在对流层低层激发出与年代际东亚夏季风环流较为相似的大气环流异常特征,表明东亚夏季风环流的年代际变化可能受大气外强迫因子PDO在对流层低层的外源强迫作用影响,最终导致东亚夏季风降水发生年代际变化。 相似文献
9.
1 INTRODUCTION Summer climate plays an especially important role in the people’s daily life around East Asia, one of the most populated regions in the world, for most of the regions receive more than 70% of the annual precipitation in summer due to the effect of monsoon climate. Global climate change caused by mankind activities have become a hot topic in recent years, though it is still not clear how these activities result in the climate change around East Asia. Successive studies (Qi… 相似文献
10.
我国夏季雨型的前期异常特征及预报方法的初步研究 总被引：5，自引：2，他引：3
用１９５１～１９９５年资料研究了我国东部夏季降水各雨型的前期大气环流及我国地面气象要素场的异常特征．结果表明,在冬季１月份北太平洋地区、秋季中国南海地区的海平面气压场有预报我国夏季雨型的信号．夏季不同雨型的前期冬季特征不同,我国的降水、气温场也有差异,４月份我国大范围的温度异常也是值得注意的预测信号．这些特征可以作为我国夏季雨型的预报信号及预报工具． 相似文献
11.
This study has investigated the possible relation between the Indian summer monsoon and the Pacific Decadal Oscillation (PDO) observed in the sea surface temperature (SST) of the North Pacific Ocean. Using long records of observations and coupled model (NCAR CCSM4) simulation, this study has found that the warm (cold) phase of the PDO is associated with deficit (excess) rainfall over India. The PDO extends its influence to the tropical Pacific and modifies the relation between the monsoon rainfall and El Niño-Southern Oscillation (ENSO). During the warm PDO period, the impact of El Niño (La Niña) on the monsoon rainfall is enhanced (reduced). A hypothesis put forward for the mechanism by which PDO affects the monsoon starts with the seasonal footprinting of SST from the North Pacific to the subtropical Pacific. This condition affects the trade winds, and either strengthens or weakens the Walker circulation over the Pacific and Indian Oceans depending on the phase of the PDO. The associated Hadley circulation in the monsoon region determines the impact of PDO on the monsoon rainfall. We suggest that knowing the phase of PDO may lead to better long-term prediction of the seasonal monsoon rainfall and the impact of ENSO on monsoon. 相似文献
12.
In this paper, we have compared and contrasted competing influences of greenhouse gases (GHG) warming and aerosol forcing on Asian summer monsoon circulation and rainfall based on CMIP5 historical simulations. Under GHG-only forcing, the land warms much faster than the ocean, magnifying the pre-industrial climatological land-ocean thermal contrast and hemispheric asymmetry, i.e., warmer northern than southern hemisphere. A steady increasing warm-ocean-warmer-land (WOWL) trend has been in effect since the 1950’s substantially increasing moisture transport from adjacent oceans, and enhancing rainfall over the Asian monsoon regions. However, under GHG warming, increased atmospheric stability due to strong reduction in mid-tropospheric and near surface relative humidity coupled to an expanding subsidence areas, associated with the Deep Tropical Squeeze (DTS, Lau and Kim, 2015b) strongly suppress monsoon convection and rainfall over subtropical and extratropical land, leading to a weakening of the Asian monsoon meridional circulation. Increased anthropogenic aerosol emission strongly masks WOWL, by over 60% over the northern hemisphere, negating to a large extent the rainfall increase due to GHG warming, and leading to a further weakening of the monsoon circulation, through increasing atmospheric stability, most likely associated with aerosol solar dimming and semi-direct effects. Overall, we find that GHG exerts stronger positive rainfall sensitivity, but less negative circulation sensitivity in SASM compared to EASM. In contrast, aerosols exert stronger negative impacts on rainfall, but less negative impacts on circulation in EASM compared to SASM. 相似文献
13.
The purpose of this study is to assess the connections between the monsoon anticyclone, gulf surges, and rainfall within the Lower Colorado River Basin (LCRB) during North American monsoon seasons from 1988-2006. The methods involved calculating rainfall characteristics and near-surface humidity for 500-hPa circulation patterns, creating circulation and near-surface humidity composites for rainfall days, and creating near-surface humidity composites for rainfall days occurring under each circulation pattern. The circulation was dominated by the monsoon anticyclone being over or to the immediate east of the basin. The anticyclone was shifted to the northwest (east) of its seasonal mean position on rainfall days in the central portion of the basin (far eastern portion of the basin). Rainfall influenced by gulf surges was most likely when the monsoon anticyclone was shifted westward, especially northwestward, of its typical position. The central portion of the basin received substantially more surge-influenced rainfall than did the far eastern portion of the basin. 相似文献
14.
ENSO 与中国东部夏季降水的关联 总被引：8，自引：1，他引：7
计算1 月减6 月El Niño 3.4 指数与6—8 月平均200、850 hPa 风场的相关矢量,分析中等或强ElNiño/La Niña 事件后的夏季(6—8 月)中国东部降水异常分布、西太平洋副热带高压异常特征。结果表明,对ENSO 的响应,无论高、底层大气环流还是西太平洋副热带高压,1970 年代中期气候突变后变为更敏感。主要表现在:对衰减的El Niño 的响应,夏季南亚高压偏东,西太平洋副热带高压偏强、偏西、偏南,印度季风、南海季风减弱,黄河下游以南副热带季风增强。黄河中下游及以南形成异常环流辐合带,由El Niño 导致的降水正异常最有可能出现在这一西南-东北的带状区域。对衰减的La Niña 响应大致相反。 相似文献
15.
Summary In 2002, India had experienced one of the most severe droughts. The severe drought conditions were caused by the unprecedented
deficient rainfall in July 2002, in which only 49% of the normal rainfall was received. One of the major circulation anomalies
observed during July 2002, was the active monsoon trough over Northwest (NW) Pacific and enhanced typhoon activity over this
region. The present study was designed to examine the long-term relationships between Tropical Cyclone (TC) activity over
NW Pacific and monsoon rainfall over India in July.
A statistically significant negative correlation between TC days over NW Pacific and July rainfall over India was observed.
Spatial dependence of the relationship revealed that TCs forming over NW Pacific east of 150° E and moving northwards have
an adverse effect on Indian monsoon rainfall. It was observed that TCs forming over the South China Sea and moving westwards
may have a positive impact on monsoon rainfall over India. Enhanced TC activity over NW Pacific during July 2002 induced weaker
monsoon circulation over the Indian region due to large-scale subsidence. 相似文献
16.
华南初夏干旱及多雨年份的季风环流特征 总被引：2，自引：0，他引：2
本文根据1961—1980年我国华南5月降水量资料,划分5月的旱或涝。并挑选1963、1966(干旱)1973、1975(涝)四年作为典型年,从天气气候角度分析了初夏季风环流结构与华南5月旱涝关系。华南地区旱5月和涝5月在夏季风来临早迟、持续期长短、强度强弱等方面都有明显差异。华南5月出现旱或涝,不仅在同期全球环流,而且在前期环流,特别是北半球中高纬度几个活动中心也有明显的差异。1月以阿留申低压及冰岛低压,4月以太平洋高压及大西洋高压差别比较明显。华南5月降水量的多少与前期3月低纬气压指标值有较好关系,涝 相似文献
17.
A continuous heavy rain visited Guangdong province during June 18-25, 2005 (named Heavy Rain 200506, HR200506) and had resulted in enormous economic loss. The ageostropic Q vectors, θse,meridional circulation, computed from the NCEP reanalysis, and TBB are used to study the rainfall processes. The results indicated that a convective system moved northwards from the South China Sea (SCS)and stayed in Guangdong for several days, which was a direct cause of HR200506. The process is a result of the activity of the South China Sea summer monsoon. There were two rainbands of HR200506 in Guangdong. One laid in the north of Guangdong that produced frontal rainfall; another situated on the south of Guangdong which produced monsoon rainfall. 相似文献
18.
热带环流异常对1998年长江流域特大洪涝的影响 总被引：1，自引：0，他引：1
分析了造成1998年长江流域特大洪涝灾害的大尺度热带环流成因。指出1998年处在热带环流强度偏弱的气候阶段，西太平洋暖池地区对流活动偏弱，南海热带季风持续异常偏弱，副热带夏季风偏强度是造成长江持续强降水的主要原因；西太平洋热带对流层高低层环流系统的异常分布，为1998年长江特大洪涝提供了有利的环流背景，还探讨了热带环流异常影响换国夏季降水的可能途径，它们的关系在1998年夏季降水预测中得到应用。 相似文献
19.
东亚海陆热力差指数及其与环流和降水的年际变化关系 总被引：32，自引：3，他引：32
利用 196 1～ 1999年海温和地温月平均资料 ,定义了一个海陆热力差指数 ,来表示东亚季风环流的纬向和经向海陆热力差异的变化强度 ,研究了夏季指数与东亚夏季风环流场和中国东部夏季降水的年际变化关系。结果表明 :(1)海陆热力差指数可用来表示东亚夏季风的强弱变化。强指数年东亚季风区低空西南夏季风气流和高层的东风气流明显偏强 ,表明这一年夏季风偏强 ,弱指数年反之。 (2 )海陆热力差指数能较好地反映东部季风区夏季降水的异常状况。强指数年 ,雨带偏北 ,江淮流域和长江中下游明显干旱 ,华南、华北降水偏多 ,弱指数年反之。这一降水异常特征可以从强弱海陆热力差指数年的环流场得到解释。 (3)海陆热力差指数所反映的东亚夏季风具有明显的准 2a和 3～ 6a周期的年际振荡 ,但其振幅和周期具有显著的年代际异常 相似文献
20.
The year 2019 experienced an excess monsoon season over the Indian region, with the seasonal rainfall being 110 % of the long period average (LPA). Several zones across the country suffered multiple extreme rainfall events and flood situations resulting in a massive loss of life and property. The first half of 2019 experienced a moderate El Niño Modoki event that lasted till mid-summer. Another important feature of 2019 was the strongest recorded positive Indian Ocean Dipole (IOD) that lasted approximately seven months from May to November. This study has examined the reasons for the intra-seasonal variability of rainfall over India during the 2019 monsoon using available remote sensing and reanalysis data. Our analysis has shown that the presence of El Niño and the formation of a very severe cyclonic storm (VSCS) in the Arabian Sea were unfavorable for the monsoon onset and its northward advancement during June. However, the Walker circulation associated with El Niño helped strengthen the IOD developed early in the Indian Ocean, much before the monsoon onset. The anomalously strong IOD strengthened the monsoon circulation during July-September and resulted in excess rainfall over India. 相似文献