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1.
大气热源和大地形对夏季印度季风和东亚季风环流形成作用的数值模拟 总被引：6，自引：1，他引：6
本文利用一个σ坐标的三层初始方程热带球圈数值模式,以全球夏季平均纬向风场为初始场,研究地形的纯动力作用和不同地区的大气热源、冷汇对亚洲夏季两支独立的季风环流系统形成的影响,针对它们对季风环流的主要成员如越赤道气流、季风槽、青藏高压等的相对重要性设计并进行了—系列试验,东亚季风环流和印度季风环流系统的成员被很好地模拟出来。 相似文献
2.
梅雨期及其前后东亚地区的经向环流结构 总被引：2，自引：1，他引：1
本文分析了1983年江淮流域入梅前、梅雨期以及出梅后东亚地区各期平均的经向环流结构及其演变特征。在不同时期,印度热带季风环流和东亚热带及副热带季风环流具有显著差异。研究指出,江淮流域梅雨是亚洲夏季三个季风系统相互作用的结果,是东亚副热带季风系统中经向环流上升支中的产物,同时又与其它两个季风系统密切相关,梅雨结束则与印度热带季风环流减弱南撤、西太平洋高压加强西伸、东亚副热带季风环流北上有关。 相似文献
3.
梅雨期及其前后东亚地区的径向环流结构 总被引：2，自引：0，他引：2
本文分析了1983年江淮流域入梅前、梅雨期以及出梅后东亚地区各期平均的径向环流结构及其演变特征。在不同时期，印度热带季风环流和东亚热带及副热带季风环流具有显著差异。研究指出，江淮流域梅雨是亚洲夏季三个季风系统相互作用的结果，是东亚副热带季风系统中径向经向环流上升支中的产物，同时又与其它两个季风系统密切相关，梅雨结束则与印度热带季风环流减弱南撤、西太平洋高压加强西伸、东亚副热带季风环流北上有关。 相似文献
4.
夏季中国南方流域性致洪暴雨与季风涌的关系 总被引：28，自引：1，他引：28
中国淮河以南地区夏季最易受到洪水灾害的威胁，这种致洪暴雨一般出现在沿着河谷走向的静止锋上。在引发致洪暴雨的环流系统中，季风涌的作用非常重要，它提供了暴雨产生所必须的水汽。分析了1998、2003、2005及2006年中国南方流域性致洪暴雨和东亚季风涌，以及与赤道附近大气环流的30～60天振荡（称作Madden—Julian Oscillation，简称MJO）活动的关系。当来自赤道印度洋的MJO引起南海地区西风的加强；南海西风的加强，触发中国南部大陆出现季风涌；季风涌与来自北方的冷空气交绥，造成静止锋上的致洪暴雨。由此提出我国南方夏季流域性致洪暴雨中、短期预报的基本思路。 相似文献
5.
1998年夏季长江上游暴雨过程的水汽输送特征 总被引：1，自引：0，他引：1
应用ECMWF再分析资料,分析了1998年夏季长江上游9次暴雨过程的水汽输送特征.结果表明:长江上游暴雨的水汽主要来源于孟加拉湾、南海和西太平洋,也存在由阿拉伯海北部经印度半岛北部再经青藏高原东南部进入长江上游的水汽路径;不同暴雨过程其水汽来源差别较大;长江上游的复杂地形和水汽输送形式的共同作用是决定长江上游暴雨发生的一个重要因素;当西太平洋副热带高压偏南、偏西、偏强,印度季风低压偏弱时,有利于长江上游暴雨的水汽输送;长江上游水汽输送的特征决定了其暴雨过程发生发展的复杂性. 相似文献
6.
随季节而变化的季风环流是与每年亚洲大陆的加热和冷却作用相联系的,它构成了大气环流的最重要的大尺度特征。印度季风是指印度洋地区低层大气的盛行风向一年之内作两次逆转变化,这主要是北部的大陆和南部的海洋之间的加热不同所造成的。“季风”一词不仅用于印度洋上的盛行风系统,而且还与非洲和南亚的热带和赤道地区的天气现象相联系。亚洲夏季季风则意味着6—9月期间的降雨。印度夏季季风与亚洲许多国家的国计民生息息相关。以往由于印度洋地区资料缺少,使研究工作受到限制。最近通过“季风试验”(MONEX)和“全球大气研究计划第一次全球试验”(FGGE),这方面的研究正在取得新的进展。 相似文献
7.
1979年东亚夏季风环流建立过程的分析 总被引：5，自引：0，他引：5
本文用1979年5—7月低纬地区的格点风资料,对东亚季风地区的逐日平均经圈环流进行了分析,发现东亚夏季风环流的建立过程和印度季风有很大不同。东亚夏季风环流建立时间较早,它是由副热带季风环流和南海热带季风环流组成的。副热带季风环流与源于南亚副热带地区的偏南风,北支高空东风相联系;而南海热带季风环流与源于澳大利亚的跨赤道气流,南支高空东风相联系。印度夏季风环流建立时间较晚,它与索马里低空急流,北支高空东风急流相联系。在季风环流的结构上,两者也是不同的,东亚季风环流是一个准经向环流圈,而印度季风环流则是一个准纬 相似文献
8.
中国气象科学研究院曾长期组织和从事东亚季风及其对中国天气和旱涝影响的研究。该文对中国气象科学研究院在东亚季风研究方面取得成果进行综述, 并回顾了20世纪50年代以来国内有关季风的研究活动, 也回顾了影响我国天气气候、东亚季风环流系统的提出及其后续的有关东亚和印度季风系统的相互作用, 引发中国大陆暴雨生成的水汽输送, 表达中国大陆季风活动的季风指数设计等研究结果。综述了南海夏季风爆发、梅雨开始、中国雨季开始及传播等有关研究成果; 东亚季风系统中副热带地区低频振荡纬向和经向传播特征及与赤道地区不同之处, 东亚低频振荡对El Ni?o形成及夏季东亚热带和副热带季风爆发的可能影响, 东亚热带和副热带季风低频振荡对中国天气气候的影响等有关成果; 亚洲地区大气热源的计算及其分布, 青藏高原夏季热源对东亚夏季风及降水的可能影响, 青藏高原冬季冷源对El Ni?o生成的可能影响等有关成果; 东亚季风及降水的年际变化特征, 准4年年际振荡的分析及与ENSO形成间的相互作用, 极地对东亚夏季降水的影响及东亚季风年代际变化特征等成果。综述东亚季风系统形成的可能机制, 特别是亚洲大陆—西太平洋海陆热力差异及非洲、印度半岛、中南半岛及澳大利亚陆地与周围海洋对冬夏季风形成、印度和东亚季风系统形成、南海夏季风形成作用的结果。 相似文献
9.
南海表面温度距平对我国夏季风和降水影响的数值试验 总被引：7，自引：1，他引：7
我国东部夏季降水不仅与副高脊线的向北推进有关,而且与对流层低层夏季季风向北推进有关。Shukla,在研究印度季风降水量对阿拉伯海域海表温度响应时也指出,对季风环流模拟的真实性直接影响印度季风降水模拟的真实性。本文以观测分析结果为依据,用英国 相似文献
10.
亚洲—太平洋夏季风系统的基本模态特征分析 总被引：5，自引：1，他引：4
亚洲—太平洋季风区各季风子系统间的相互作用对季风区甚至全球的气候变化都有着显著的影响.整个亚洲—太平洋夏季风系统都处于高层辐散、低层辐合的庞大辐散环流中,从高层辐散中心流出的三支气流分别对推动印度夏季风、东亚副热带夏季风和南海夏季风起着重要的作用,很好地表现了亚洲—太平洋夏季风系统的整体性特征.季风区多种气象要素的基本模态在年代际和年际尺度上都表现出较为一致的变化特征:年代际尺度上亚洲—太平洋夏季风系统整体呈现减弱趋势;年际尺度上存在准2年和准4年的两个周期,其中准2年振荡特征表现为若印度西南季风偏强,则印度季风雨带偏强偏北,导致印度大陆中北部地区降水偏多;同时,由于西太平洋副热带高压的北移和偏强的印度西南季风显著向东延伸,10°N~30°N范围内的西北太平洋地区则表现为异常的气旋性环流,而30°N~50°N之间为反气旋性环流异常,对应东亚夏季风偏强,季风雨带能够北推至我国华北地区.也就是说,当亚洲夏季风中某一季风子系统表现为异常偏强时,另一季风子系统在这一年中也将表现为异常偏强,反之亦然.准2年的振荡周期可能是亚洲—太平洋夏季风系统的一种固有振荡,它从年际尺度上反映了亚洲—太平洋夏季风受热带太平洋—印度洋海温的强迫表现出明显的整体一致特征. 相似文献
11.
THE RELATIONSHIP BETWEEN INDIAN MONSOON SYSTEMS IN SUMMER AND THE CONTINUOUS HEAVY RAIN OVER THE UPPER REACHES OF CHANGJIANG RIVER 
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下载免费PDF全文 In this paper,the continuous heavy rains over the upper reaches of Changjiang River during June—Augustare analyzed.They are closely related to the Indian monsoon systems.The average synoptic situationsand the average distributions of some meteorological elements over the Bay of Bengal during the period ofheavy rains are presented.The correlation coefficients between meteorological elements and rainfall arecalculated and the main monsoon influence systems and the key regions are denoted.Results can be usedas a reference in the 24 h forecast of rainfall. 相似文献
12.
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
13.
14.
Summary The west coast of the Indian peninsula receives very heavy rainfall during the summer Monsoon (June–September) season with
average rainfall over some parts exceeding 250 cm. Heavy rainfall events with rainfall more than 15 cm day−1 at one or more stations along the west coast of India occur frequently and cause considerable damage. A special observational
programme, Arabian Sea Monsoon Experiment, was carried out during the monsoon season of 2002 to study these events. The spatial
and temporal distributions of intense rainfall events, presented here, were used for the planning of this observational campaign.
The present study using daily rainfall data for summer monsoon season of 37 years (1951–1987) shows that the probability of
getting intense rainfall is the maximum between 14° N–16° N and near 19° N. The probability of occurrence of these intense
rainfall events is high from mid June to mid August, with a dip in early July. It has been believed for a long time that offshore
troughs and vortices are responsible for these intense rainfall events. However, analysis of the characteristics of cloud
systems associated with the intense rainfall events during 1985–1988 using very high resolution brightness temperature data
from INSAT-IB satellite shows that the cloud systems during these events are characterized by large spatial scales and high cloud tops.
Further study using daily satellite derived outgoing longwave radiation (OLR) data over a longer period (1975–1998) shows
that, most of these events (about 62%) are associated with systems organized on synoptic and larger scales. We find that most
of the offshore convective systems responsible for intense rainfall along the west coast of India are linked to the atmospheric
conditions over equatorial Indian Ocean. 相似文献
15.
Investigations into the climatic forcings that affect the long-term variability of the Indian summer monsoon are constrained by a lack of reliable rainfall data prior to the late nineteenth century. Extensive qualitative and quantitative meteorological information for the pre-instrumental period exists within historical documents, although these materials have been largely unexplored. This paper presents the first reconstruction of monsoon variability using documentary sources, focussing on western India for the period 1781–1860. Three separate reconstructions are generated, for (1) Mumbai, (2) Pune and (3) the area of Gujarat bordering the Gulf of Khambat. A composite chronology is then produced from the three reconstructions, termed the Western India Monsoon Rainfall reconstruction (WIMR). The WIMR exhibits four periods of generally deficient monsoon rainfall (1780–1785, 1799–1806, 1830–1838 and 1845–1857) and three of above-normal rainfall (1788–1794, 1813–1828 and 1839–1844). The WIMR shows good correspondence with a dendroclimatic drought reconstruction for Kerala, although agreement with the western Indian portion of the tree-ring derived Monsoon Asia Drought Atlas is less strong. The reconstruction is used to examine the long-term relationship between the El Nino-Southern Oscillation (ENSO) and monsoon rainfall over western India. This exhibits peaks and troughs in correlation over time, suggesting a regular long-term fluctuation. This may be an internal oscillation in the ENSO-monsoon system or may be related to volcanic aerosol forcings. Further reconstructions of monsoon rainfall are necessary to validate this. The study highlights uncertainties in existing published rainfall records for 1817–1846 for western India. 相似文献
16.
Summary The spatial organization of Monsoon rainfall over Sri Lanka is examined using Orthogonal Factor Analysis (OFA) on long-term mean monthly rainfall data. Three types of orthogonal structure of Monsoon regime in Sri Lanka have been identified. Interpretation of orthogonal factor scores revealed that a large amount of rainfall occurs from March to October in the southwestern parts of Sri Lanka, from December to February in the eastern parts, and in November in the northern and mid-western parts which are all represented by high positive factor scores. Orthogonal factor scores for the first three factors account for 93.6% of the total variance of mean monthly rainfall and clearly indicate that the southeast and northwest parts of the country with lowest rainfall, resulting from lack of Monsoons, are represented by negative factor scores. The three orthogonal factors identified different rainfall maxima in different time periods and, additionally, significant spatial differences between regions. Seasonal changes in the Monsoon wind system, ITCZ weather phenomena, and topography were the main factors which influence the spatial structure of Monsoon rainfall over Sri Lanka.With 4 Figures 相似文献
17.
ABRUPT CHANGE IN ELEMENTS AROUND 1998 SCS SUMMER MONSOON ESTABLISHMENT WITH ANALYSIS OF ITS CHARACTERISTIC PROCESS 总被引：1，自引：0，他引：1 下载免费PDF全文
下载免费PDF全文 The latest dataset from the SCS(South China Sea)Monsoon Experiment is used to investigatethe features of abrupt change in some meteorological elements before,during and after the summermonsoon's establishment in 1998 and explore its onset characteristic process.We have arrived at apreliminary conclusion that the 1998 Asian summer monsoon is established first in the SCS as earlyas May 23,which is representative of the earliest indicator of the conversion from a winter into asummer monsoon situation in Asia;the continued retreat eastward of the western Pacificsubtropical high from the SCS region has direct effect on the SCS summer monsoon establishmentbecause the withdrawal favors the release of unstable energy,responsible for the sudden onset ofthe monsoon.Our tentative investigation indicates that the eastward extension of the westerly andrainfall band from the equatorial Indian Ocean into the Indo-China Peninsula and the southwardspreading of an active South-China stationary front,acting as the interaction between mid and lowlatitude systems,are likely to be the characteristic events contributing to the subtropical high'seastward retreating and the summer monsoon's onset over the SCS. 相似文献
18.
ABRUPT CHANGE IN ELEMENTS AROUND 1998 SCS SUMMER MONSOON ESTABLISHMENT WITH ANALYSIS OF ITS CHARACTERISTIC PROCESS* 下载免费PDF全文
下载免费PDF全文 The latest dataset from the SCS(South China Sea) Monsoon Experiment is used to investigate the features of abrupt change in some meteorological elements before,during and after the summer monsoon's establishment in 1998 and explore its onset characteristic process.We have arrived at a preliminary conclusion that the 1998 Asian summer monsoon is established first in the SCS as early as May 23,which is representative of the earliest indicator of the conversion from a winter into a summer monsoon situation in Asia;the continued retreat eastward of the western Pacific subtropical high from the SCS region has direct effect on the SCS summer monsoon establishment because the withdrawal favors the release of unstable energy,responsible for the sudden onset of the monsoon.Our tentative investigation indicates that the eastward extension of the westerly and rainfall band from the equatorial Indian Ocean into the Indo-China Peninsula and the southward spreading of an active South-China stationary front,acting as the interaction between mid and low latitude systems,are likely to be the characteristic events contributing to the subtropical high's eastward retreating and the summer monsoon's onset over the SCS. 相似文献
19.
Synoptic systems and microphysical properties associated with a sea fog event are
analyzed based on the measurements of visibility, meteorological elements and fog droplet
spectrum from a comprehensive field campaign in Xiamen, Fujian province during spring 2013.
The influences of meteorological elements on the microstructures of the sea fog are also
discussed. The results showed that the wind speed and direction changed suddenly during the
intermittent and disperse phases of the sea fog. Liquid water content, number concentration
and average diameter varied obviously in the development, mature and disperse phases of the
sea fog. The burst re-enforcement of sea fog was accompanied by explosive broadening of fog
droplet spectrum; average diameter, number concentration and liquid water content increased
sharply; and background meteorological conditions also changed significantly. The
microstructures fluctuated intensely due to changes in turbulence, radiation and
meteorological conditions at different stages, including nucleation, condensation,
coagulation, and evaporation, as well as the discontinuity of spatial distribution of
droplets. 相似文献
20.
2012年南海夏季风活跃期与非活跃期广东电白地区海陆大气边界层特征分析 总被引：2，自引：0，他引：2
利用2012年6—9月南海夏季风期间的近海海洋气象观测平台 (海上平台站) 和电白国家气候观象台 (电白站) 的地面气象站资料,气象塔资料以及GPS探空资料对海上平台站和电白站两站在季风活跃期和非活跃期的大气边界层结构特征进行研究分析。结果表明,活跃期与非活跃期两地的大气边界层结构特征有明显差异。(1) 在活跃期两站近地层风向全天由东南风主导,风速较大,且两站均出现连续降水,受云系和降水的影响,与非活跃期相比,电白站近地层日平均气温降低约为2 ℃;非活跃期两站风向全天无规则变化,且风速值小。(2) 在活跃期大气边界层内风向均为一致的东南风,风速较大,200 m以上的风速均大于8 m/s,而在非活跃期大气边界层内风速较小,风向变化较大,同一时刻不同高度的风向差可达180 °。(3) 在季风非活跃期混合层高度最高可达937 m,而在活跃期,受降水和云系的影响混合层高度明显降低,最大高度仅为700 m左右。(4) 活跃期受连续降水影响,大部分时刻的大气边界层内相对湿度大于80%。由此可见在季风活跃期与非活跃期不仅海陆气能量交换发生变化,大气边界层结构特征也有显著变化。 相似文献