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1.
利用燕山南麓1951-2005年夏季降水资料和NCEP再分析资料,采用统计分析等方法,对燕山南麓夏季降水演变规律进行了研究.结果表明:近55 a来,燕山南麓夏季降水线性减少趋势显著,平均每10 a年减少29 mm,夏季降水在20世纪70年代末发生了一次气候突变.燕山南麓夏季降水和东亚夏季风变化周期不一致.燕山南麓夏季降水减少主要是由于亚洲中纬度地区和极地地区环流变化造成的. 相似文献
2.
利用贵州地区52个测站1961～2000年夏季(6～8月)降水资料，采用突变分析、小波分析等方法，对贵州夏季降水的时间变化特征进行了诊断分析，并运用均生函数对贵州夏季降水建立预测模型，进行试报和预报检验。结果表明：贵州地区近40a来夏季降水呈上升趋势，具有明显的年际变化特征；夏季降水比较明显的突变点出现在1971年和1994年(没有通过显著水平a=0．05的信度检验)，其1971年后到1994年前降水为减少趋势，1994年后降水开始增多；夏季降水在年际尺度上主要存在显著的准2a、准4a和4～6a、8～10a周期振荡；均生函数对夏季降水预测效果较好，尤其对极值的预测，效果更加明显。 相似文献
3.
根据1961—2000年辽宁地区降水资料,将辽宁地区降水划分为4个区,分析各分区降水的年际、年代际、季节变化以及周期特征。结果表明:辽宁南部和东南部地区降水明显减少;自20世纪90年代开始,东南部和南部地区降水显著减少,而中部地区降水增加;东南部地区的夏冬季和南部地区的冬季降水减少,西部地区春季降水增多。周期特征为春季和冬季周期为2 a或4 a,夏季和秋季为10 a。各分区夏季降水的影响因子不同,辽南地区多雨年东亚槽明显加深,东南区多雨年东亚槽略有加深并且偏东;南部和东南部夏季降水与副热带高压系统相关显著;各区夏季降水与太阳黑子负相关较好,其中8月相关显著,南部和中部相关性均好于东南部和西部地区。 相似文献
4.
近45a辽宁夏季降水的气候特征 总被引：7，自引：0，他引：7
利用1961～2005年辽宁省53个测站,6～8月降水量资料,采用EOF、趋势分析等方法,对辽宁地区夏季降水量的空间分布特征和时间演变规律进行了诊断分析研究。结果表明：辽宁地区夏季降水的空间分布既有整体一致的性质,也存在东南部和西北部相反变化的差异。近45 a来,辽宁地区夏季降水有减少趋势,并且存在着4～6 a的周期变化。辽宁夏季及其各月降水都有明显的年代际变化特征,20世纪60年代夏季降水处于偏多时段,70年代偏少,80年代和90年代偏多,进入21世纪的前5 a降水偏少。 相似文献
5.
利用淮海地区1955—2004年23个气象站点的逐日降水资料,分析了淮海地区降水的主要周期振荡以及突变点,结果表明:该地区降水均有多个时间尺度的周期变化特征,降水周期变化显著,干湿交替现象明显;降水的年代际以及年际尺度的主要周期:年降水为12a、9a、5a,春季降水为14a、6a、3a,夏季为10a、4a,秋季为21a、10a、7a,冬季为18a、5a。年降水减少趋势明显,在1967年发生了突变,由相对多雨期转入相对少雨期;春季、夏季、秋季降水都有不同程度的减少趋势,而冬季降水则表现为增加的趋势。 相似文献
6.
利用1951～2004年计54 a鞍山市逐年春夏季降水资料,采用线性趋势估计法、小波分析方法等统计学方法,分析了鞍山市半个世纪以来春夏季降水的变化特征。结果表明:鞍山市春季降水线性变化趋势为增加趋势,其线性变率为2 mm/10 a,夏季降水线性变化趋势为减少趋势,其线性变率为5 mm/10 a,并且从80年代开始春夏季降水的不稳定性开始增强。春季降水存在着4～6 a和16～18 a的主要变化周期,夏季降水有18～20 a和6～8 a的主要变化周期,各周期变化在不同时期起着主导作用。 相似文献
7.
采用东北地区99个测站1960～2000年逐日降水资料，运用小波分析、突变分析、旋转EOF等方法，研究了东北地区不同区域夏季降水的长期变化特征。结果表明，东北地区夏季降水呈减少趋势，并存在14年和2～4年的变化周期。东北地区夏季降水异常可分为5种空间分布类型：东北西南部型、东北东南部型，东北东北部型、东北西北部型、东北中部型。东北东南部地区夏季降水减少趋势最明显，东北西南部降水的增加趋势最明显。各区域降水的变化周期有所区别，东北东北部存在16～18年的变化周期，其它地区存在10～14年的变化周期，各区域降水突变的时间主要在60年代和80年代。 相似文献
8.
利用六盘水市1961-2000年近40 a夏季(6-8)月降水资料,采用小波分析、二项式系数加权滑动平均等方法,对六盘水地区夏季降水异常进行了分析,结果表明:六盘水夏季降水近40 a来呈上升趋势,具有明显的年际、年代际变化特征;降水存在显著的12~14 a、准6 a、2~4 a左右的振荡周期;近40 a来降水变化的能量主要集中在较小时间尺度的演变上。 相似文献
9.
利用中国160站1951-2005年的逐月降水资料,以华北17站夏季降水异常为研究对象,在对其时空变化特征进行分析的基础上,探讨了影响其异常的同期因子——该地区上空大尺度环流异常特征.研究结果表明,华北夏季降水在55a里总的趋势是减少的,该地区干旱化的趋势明显,华北夏季降水存在准3a、准6a、准8a的年际周期和17～19a的年代际振荡周期。在华北夏季降水异常的年份,其降水通常与江南和华南的呈现反位相。在低层850hPa,当贝加尔湖地区的东北气流、中南半岛的西南气流及青藏高原北侧的偏西气流较常年偏强时,华北夏季降水较常年偏多;中层500hPa,副热带高压较常年偏弱、偏北、偏西,冷空气偏强,低纬热带季风活跃,南方水汽也供应充沛,从而华北多雨. 相似文献
10.
用统计方法对冀中平原地区1957—2004近50 a的气温和降水资料进行分析,发现:冀中平原年气温变化存在15 a和5 a左右的周期振荡,气候突变发生在20世纪80年代中期。冬季气温变化趋势与年气温变化趋势非常一致,夏季气温变化与年气温变化明显不同,春、秋季气温变化趋势与年气温变化趋势基本一致,目前,年气温和四个季节气温都处于升高偏暖时期,冬季气温上升比其他季节更为明显。冀中平原年降水存在10~15 a和4 a的短周期振荡,气候突变发生在1987年。春、秋、冬3个季节降水现在基本上都为增多趋势,与年降水变化趋势不一致,只有夏季降水变化趋势与年降水变化趋势比较一致,为减少的趋势。 相似文献
11.
Possible Impacts of the Arctic Oscillation on the Interdecadal Variation of Summer Monsoon Rainfall in East Asia 总被引：18，自引：5，他引：18
The influences of the wintertime AO (Arctic Oscillation) on the interdecadal variation of summer monsoon rainfall in East Asia were examined. An interdecadal abrupt change was found by the end of the 1970s in the variation of the AO index and the leading principal component time series of the summer rainfall in East Asia, The rainfall anomaly changed from below normal to above normal in central China, the southern part of northeastern China and the Korean peninsula around 1978. However,the opposite interdecadal variation was found in the rainfall anomaly in North China and South China.The interdecadal variation of summer rainfall is associated with the weakening of the East Asia summer monsoon circulation. It is indicated that the interdecadal variation of the AO exerts an influence on the weakening of the monsoon circulation. The recent trend in the AO toward its high-index polarity during the past two decades plays important roles in the land-sea contrast anomalies and wintertime precipitation anomaly. The mid- and high-latitude regions of the Asian continent are warming, while the low-latitude regions are cooling in winter and spring along with the AO entering its high-index polarity after the late 1970s. In the meantime, the precipitation over the Tibetan Plateau and South China is excessive, implying an increase of soil moisture. The cooling tendency of the land in the southern part of Asia will persist until summer because of the memory of soil moisture. So the warming of the Asian continent is relatively slow in summer. Moreover, the Indian Ocean and Pacific Ocean which are located southward and eastward of the Asian land, are warming from winter to summer. This suggests that the contrast between the land and sea is decreased in summer. The interdecadal decrease of the land-sea heat contrast finally leads to the weakening of the East Asia summer monsoon circulation. 相似文献
12.
It is well known that suppressed convection in the tropical western North Pacific(WNP) induces an anticyclonic anomaly,and this anticyclonic anomaly results in more rainfall along the East Asian rain band through more water vapor transport during summer, as well as early and middle summer. However, the present results indicate that during late summer(from mid-August to the beginning of September), the anomalous anticyclone leads to more rainfall over central southern China(CSC), a region quite different from preceding periods. The uniqueness of late summer is found to be related to the dramatic change in climatological monsoon flows: southerlies over southern China during early and middle summer but easterlies during late summer. Therefore, the anomalous anticyclone, which shows a southerly anomaly over southern China, enhances monsoonal southerlies and induces more rainfall along the rain band during early and middle summer. During late summer,however, the anomalous anticyclone reflects a complicated change in monsoon flows: it changes the path, rather than the intensity, of monsoon flows. Specifically, during late summers of suppressed convection in the tropical WNP, southerlies dominate from the South China Sea to southern China, and during late summers of enhanced convection, northeasterlies dominate from the East China Sea to southern China, causing more and less rainfall in CSC, respectively. 相似文献
13.
南海季风爆发的年代际转折与东亚副热带夏季降水的关系 总被引：1，自引：0，他引：1
利用1979—2016年NCEP再分析资料, 分析了南海季风爆发的年代际转折与东亚副热带夏季降水的关系。结果表明:南海夏季风爆发时间在1993/1994年出现年代际转变, 1979—1993年爆发时间相对偏晚, 夏季华南降水偏少, 长江中下游至日本南部降水偏多; 1994—2016年爆发时间偏早, 夏季华南降水偏多, 长江中下游到日本南部降水偏少。南海季风爆发时间年代际转折与夏季东亚副热带降水关系可能受到菲律宾越赤道气流强度的调控, 季风爆发时间与菲律宾越赤道气流有显著正相关, 且均在1993/1994年间存在年代际转变。在1994—2016(1979—1993)年南海夏季风爆发偏早(晚), 菲律宾越赤道气流偏弱(强), 澳大利亚北部有偏北(南)风异常, 将暖池的热量往赤道输送, 使得赤道对流增强(减弱), 产生异常上升(下沉)运动汇入Hadley环流上升支, 增强(减弱)的Hadley环流导致下沉主体偏北(南), 促使副高脊线偏北(南), 从西北太平洋(孟加拉湾)往华南地区(江淮到日本南部)输送水汽增强, 所以华南(江淮到日本南部)夏季降水偏多。 相似文献
14.
Renguang WU 《大气科学进展》2017,34(1):4-15
The Indian and East Asian summer monsoons are two components of the whole Asian summer monsoon system.Previous studies have indicated in-phase and out-of-phase variations between Indian and East Asian summer rainfall.The present study reviews the current understanding of the connection between Indian and East Asian summer rainfall.The review covers the relationship of northern China,southern Japan,and South Korean summer rainfall with Indian summer rainfall;the atmospheric circulation anomalies connecting Indian and East Asian summer rainfall variations; the long-term change in the connection between Indian and northern China rainfall and the plausible reasons for the change; and the influence of ENSO on the relationship between Indian and East Asian summer rainfall and its change.While much progress has been made about the relationship between Indian and East Asian summer rainfall variations,there are several remaining issues that need investigation.These include the processes involved in the connection between Indian and East Asian summer rainfall,the non-stationarity of the connection and the plausible reasons,the influences of ENSO on the relationship,the performance of climate models in simulating the relationship between Indian and East Asian summer rainfall,and the relationship between Indian and East Asian rainfall intraseasonal fluctuations. 相似文献
15.
华北和印度夏季风降水变化的对比分析 总被引：3，自引：0，他引：3
利用华北和印度夏季降水资料，采用趋势分析、小波变换等方法，对两地区夏季风降水进行了对比分析。结果表明：1) 华北和印度夏季风降水量都存在线性减少倾向，但华北更为显著，减少达16 mm/10 a；2) 华北和印度夏季风降水变化都以18 a周期为主，近年都有逐渐缩短的趋势，而印度的这种周期缩短得比华北更快，近年降水变化周期接近15 a；3) 华北和印度夏季风降水变化在1956、1976、1992/1993年发生了趋势转折；4) 华北和印度降水量主要集中在6-9月，夏季风降水特征非常明显，但两地变化特征表现不尽相同。 相似文献
16.
The Relationship between Precipitation and Airflow over the Tibetan Plateau in Boreal Summer 
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下载免费PDF全文 Based on the observation data and the reanalysis datasets, the variability and the circulation features influencing precipitation in the Tibetan Plateau (TP) are investigated. Taking into account the effects of topography, surface winds are deconstructed into flow-around and flow-over components relative to the TP. Climatologically, the flow-around component mainly represents cyclonic circulation in the TP during the summer. The transition zone of total precipitation in the summer parallels the convergence belt between the southerlies and the northerlies of the flow-over component. The leading mode of rainfall anomalies in the TP has a meridional dipole structure, and the first principal component (PC1) mainly depicts the variation of rainfall in the southern TP. The wet southern TP experiences strengthened flow-over, which in turn mechanistically favors intensified ascent forced by the flow-over component. In addition, variations in the Indian summer monsoon (ISM) have an important role in influencing the flow over the southern TP, and the ISM ultimately impacts the precipitation over southern TP. 相似文献
17.
On the onset of the south china sea summer monsoon in 1998 总被引：21，自引：0，他引：21
1.IntroductionChinesescientistshavepointedoutsincethe1980sthattheAsiansummermonsooniscomposedoftheSouthAsian(Indian)monsoonsystemandtheEastAsianmonsoonsystem,whichhavetheirparticularcharacteristicsrespectivelybutalsointeractoneachother;andtheAsiansummermonsoonbreaksoutintheSouthChinaSea(SCS)regionatfirst,thenspreadsnorthwestwardandnorthwardrespectively,finallytheSouthAsiansummermonsoonandtheEastAsiansummermonsoonaresetup(TaoandChen,1987;JinandChen,1985;Zhuetal.,1986).Muchattentionhasbe… 相似文献
18.
通过对观测资料和大气再分析资料的诊断分析,研究了影响江西省夏季降水变率的物理机制。结果表明江西省夏季降水存在显著的年际变率。极端条件下,降水偏多的夏季可达降水偏少的夏季的降水量的三倍。中纬度地区的准静止波列和热带关键海区的海温异常是造成江西夏季降水异常的主要原因。当江西省夏季降水偏多时,欧亚大陆地区存在"正—负—正"的准正压Rossby波列结构,位于贝加尔湖的正活动中心能引导干冷空气南下,从而有利于江南地区的锋生和江西降水的增加。此外,当江西省夏季降水偏多时,前期冬季中东太平洋地区有El Ni1o事件的活动,并能通过大气桥在夏季印度洋地区形成正海温异常。通过"印度洋电容器"机制,印度洋的暖海温能激发向东传播的Kelvin波,引起菲律宾地区降水的减少。菲律宾地区抑制的降水能激发向北传播的EAP/PJ波列,使得西太平洋副热带高压西伸增强,从而有利于水汽向江南地区的输送,并造成江西夏季的降水增加。 相似文献
19.
This study investigates the relationship between summer low-frequency rainfall over southern China and tropical intraseasonal oscillation (ISO) in the atmosphere by examining systematically the propagation features of the tropical ISO in terms of focusing on five large-scale low-frequency rainfall regimes in summer over southern China. It is demonstrated that there is a close linkage between the five rainfall regimes over southern China and the northward propagation of the tropical ISO. The moist ISO signals, which influence the low-frequency rainfall events in different regions of southern China, mainly propagate northwestward from the tropical ocean to the southeast of China. The southeast China rainfall regime is intimately associated with the moist ISO signals propagating northwestward from the equatorial mid-western Pacific Ocean. For both the Yangtze River regime and South of Yangtze River regime, the moist ISO signals over the northern South China Sea show an evident northward propagation towards the Yangtze River region, and then propagate westward. It is further found that the interaction between the northward propagation of low-latitude ISO signals and the southward propagation of high-latitude ISO signals can also make a clear influence on the low-frequency rainfall in southern China. For the Southern China regime, the moist ISO signals show a significant northward propagation from the Philippines. Moreover, for the rainless regime, southern China is under dry ISO signals’ control, and the latter shows no clear propagation to southern China. This study may provide insights for the extended-range forecasting of summer rainfall in southern China. 相似文献