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1.
江淮北区6~7月降水异常与北太平洋海温的SVD分析   总被引:2,自引:6,他引:2  
REOF结果表明,江淮地区6~7月降水可以分为南、北两个区;江淮北区6~7月降水和海温的SVD分析结果表明:影响江淮北区6~7月降水异常的海温关键区(关键区)是北太平洋海域,关键时段是当年的1~2月;当年1~2月北太平洋关键区海温异常偏高(偏低),同年6~7月中国的江淮、华南、东北地区降水偏多(少),华北、西北、西南呈降水偏少(多),其中江淮北区相关系数绝对值最大,通过0.05的Monte-Carlo显著性水平检验。  相似文献   

2.
中国东部气温异常型与海表温度异常模关系的诊断   总被引:2,自引:1,他引:1  
关惠戈  余锦华 《气象科学》2014,34(6):656-665
基于国家气候中心整编的160站常规观测气温资料和HADLEY中心的海表温度资料,应用最大协方差分析方法,诊断了中国东部各季节气温异常型和前期海表温度异常(SSTA)模的关系,并重点分析冬季气温与SSTA模的最佳耦合模态及海温异常对大气环流的影响。结果表明:中国东部四季气温异常型与前期海盆SSTA模的显著耦合关系表现出不同的特征。超前6个月的热带太平洋第二模和南印度洋第二模与东部地区冬季气温一致变化型耦合关系最佳。西南冷东北暖的气温异常型与超前4个月热带大西洋一致增暖模有最佳耦合关系。大气环流对与全区气温一致偏冷型对应的SSTA模的回归表现为:西伯利亚高压和阿留申低压增强,东亚大槽加深,中纬度西风加强。对与气温西南冷东北暖型对应的SSTA模的回归表现为:西伯利亚高压和阿留申低压略有增强,东亚大槽槽区附近位势升高,大槽变浅,槽线偏向西南,东部40°N以北风速加强,以南风速减弱。  相似文献   

3.
利用1951—2016年Hadley中心海温资料、NCEP/NCAR再分析资料和全国160站气温资料,研究了夏季北大西洋三极型海温异常与中国气温年际变化的联系及可能机制。结果表明,夏季北大西洋三极型海温异常与同期中国西南地区气温年际变化存在显著的负相关关系。夏季北大西洋“-+-”三极型海温异常激发的北半球中高纬欧亚遥相关波列,引起贝加尔湖地区位势高度升高,产生反气旋性环流异常,并引起东亚地区位势高度降低,产生气旋性环流异常。西南地区在对流层中下层位于贝加尔湖异常反气旋性环流的东部和东亚异常气旋性环流的西部,在两者的共同作用下,受异常偏北气流影响,有利于冷空气南下和堆积。与此同时,对流层高层的东亚副热带西风急流位置偏南,西南地区位于急流南侧的异常上升气流中。此种环流形势配置导致中国西南地区气温降低,反之亦然。  相似文献   

4.
利用53年的NCEP/NCAR再分析资料和英国气象局Hadley气候预测和研究中心的海表面温度资料,使用SVD方法研究了东亚-北太平洋地区表层海温(SST)异常与大气环流异常间的主要耦合模态.分析结果表明,中纬度北太平洋地区存在两种主要的海-气耦合模态,第一模态是海温异常分布的纬向型,第二模态主要表现为经向海温差异分布.两种空间耦合模态共同反映出中纬度北太平洋地区大气和海洋的异常中心有很强的局地耦合性.在第一模态的正(负)异常年,东亚-北太平洋地区主要为负(正)的降水异常,在第二模态的正(负)异常年,东亚和北太平洋的大部分地区出现降水正(负)异常,北美西岸及以西的部分区域出现降水的负(正)异常.两个模态所对应的降水差异显示,海气耦合模态的循环变化有利于形成我国降水分布南北差异的改变.  相似文献   

5.
利用HadISST OI海温和中国东北地区92站逐日气温资料,使用广义平衡反馈分析方法(GEFA)结合EOF分析方法(GEFA-EOF)研究了近50a中国东北地区冬季气温对海表温度异常(SSTA)的响应.结果表明:对于热带和北半球中纬度5个海盆来说,东北地区冬季气温异常与同期热带大西洋和北大西洋海温异常有密切关系,与其他海盆关系不显著;热带大西洋的"正—负—正"三极型模态(TA3)以及北大西洋纬向上"正—负—正"三极型模态(NA3)分别对东北地区冬季气温的异常偏低和偏高有显著的强迫作用,且对北部地区的强迫作用大于南部地区.热带大西洋和北大西洋对东北地区冬季气温异常影响的可能途径为:热带大西洋TA3模态通过在北半球激发的"正—负—正"的遥相关波列,致使东亚大槽移至贝加尔湖地区,有利于极地冷空气南下至东北地区,导致该地区的冷冬;北大西洋的"正—负—正"三极型模态(NA3)直接响应使得东亚大槽减弱消失,极地冷空气南下受阻,导致该地区冬季气温异常偏高.  相似文献   

6.
EFFECTS OF INDIAN OCEAN SSTA WITH ENSO ON WINTER RAINFALL IN CHINA   总被引:2,自引:1,他引:1  
Based on Hadley Center monthly global SST, 1960-2009 NCEP/NCAR reanalysis data and observation rainfall data over 160 stations across China, the combined effect of Indian Ocean Dipole (IOD) and Pacific SSTA (ENSO) on winter rainfall in China and their different roles are investigated in the work. The study focuses on the differences among the winter precipitation pattern during the years with Indian Ocean Dipole (IOD) only, ENSO only, and IOD and ENSO concurrence. It is shown that although the occurrences of the sea surface temperature anomalies of IOD and ENSO are of a high degree of synergy, their impacts on the winter precipitation are not the same. In the year with positive phase of IOD, the winter rainfall will be more than normal in Southwest China (except western Yunnan), North China and Northeast China while it will be less in Yangtze River and Huaihe River Basins. The result is contrary during the year with negative phase of IOD. However, the impact of IOD positive phase on winter precipitation is more significant than that of the negative phase. When the IOD appears along with ENSO, the ENSO signal will enhance the influence of IOD on winter precipitation of Southwest China (except western Yunnan), Inner Mongolia and Northeast China. In addition, this paper makes a preliminary analysis of the circulation causes of the relationship between IOD and the winter rainfall in China.  相似文献   

7.
Under the background of global warming, summer (JJA) low temperature events in Northeast China had not occurred for about 15 yr since 1994, but one such event took place in 2009. By using the NCEP/NCAR reanalysis data, the 100-yr station temperature data at Harbin and Changchun, and the Hadley Center sea surface temperature (SST) data, this paper intends to reveal the cause, circulation background, and influencing factors of this event. Analysis of both horizontal and vertical circulations of a low-value system over Northeast China in summer 2009 during the low temperature event shows that anomalous activities of the Northeast China cold vortex (NECV) played the most direct role. A decadal cooling trend of-0.8 C (10 yr)-1 over 1999-2008 at Changchun and Harbin was found, which is obviously out-of-phase with the linear warming trend (0.2 C (10 yr)-1 ) over 1961-2000 for Northeast China in response to the global warming. The previous winter North Pacific polar vortex (NPPV) area index, significantly positively related to the observed summer temperatures of Harbin and Changchun, was also in a significantly declining tendency. These provide favorable decadal backgrounds for the 2009 low temperature event. Different from the average anomaly field of 500-hPa height for summer 1994-2008 in Northeast China, in the summer of 2009, the Arctic Oscillation (AO) showed a strong negative phase distribution, and significant negative height anomalies dominated Northeast Asia, Aleutian Islands, and North Atlantic. Furthermore, the negative phase of North Pacific Oscillation (NPO) in the winter of 2008 was obviously strong, and it maintained in the spring of 2009. Meanwhile, the SSTA in the equatorial eastern-central Pacific Ocean in the winter of 2008 showed a La Nina phase, but the strength of the La Nina weakened obviously in the spring of 2009. The abnormally strong activities of NECV in June and July of 2009 were related to the disturbances of stationary waves that replaced the original ultra-long waves over the North Pacific region in April and May 2009. The singular value decomposition (SVD) and harmonic analysis results suggest that the anomalous phase of NPO is an important precursor for summer temperature variations over Northeast China, and also a stable planetary-scale component that can be extracted from the atmospheric circulation in addition to the chaotic components on the synoptic scale.  相似文献   

8.
分析了近55 a来中国冬季气温变化特征及其与大尺度环流异常的关系,结果显示:1) 中国冬季气温变化有两个主要空间模态,第一模态表现为20世纪80年代中期以后全国一致变暖;第二模态表现为80年代以后东北、西北地区冬季气温升高,而西南、华南地区气温降低。2) 西伯利亚高压变化与中国冬季气温变化的第一模态关系密切,当西伯利亚高压偏强时,我国大部分地区气温偏低,反之亦然。3) 北极涛动(AO)与冬季气温变化的第二模态关系密切,它与中国冬季气温相关最显著的区域主要在东北和西北地区,当AO为正位相时,上述区域气温往往偏高。  相似文献   

9.
By using 1958-2001 NOAA extended reconstructed sea surface temperature(SST) data, ERA40 reanalysis soil moisture data and precipitation data of 444 stations in China(east of 100°E), the possible relationships among South China Sea(SCS) SST anomaly(SSTA), soil moisture anomalies(SMA) and summer precipitation in eastern China as well as their possible physical processes are investigated. Results show that the SSTA of SCS bears an evidently negative correlation with spring soil moisture in the east part of Southwest China. More(less) precipitation happens in the Yangtze River basin and less(more) in the Southeast China in summer when the SSTA of SCS is higher(lower) than normal and the soil in the east part of Southwest China is dry(wet) in spring. Further analysis shows that when the SSTA of SCS is high(low), the southwesterly wind at low level is weak(strong), decreasing(increasing) the water vapor transport in South China, resulting in reduced(increased) spring precipitation in the east part of Southwest China and more(less) soil moisture in spring. Through the evaporation feedback mechanism, the dry(wet) soil makes the surface temperature higher(lower) in summer, causing the westward extension(eastward retreat) of the West Pacific Subtropical High, eventually leading to the summer precipitation anomalies.  相似文献   

10.
ENSO与中国夏季年际气候异常关系的年代际变化   总被引:17,自引:6,他引:17  
利用热带太平洋海表温度和中国降水和气温站点观测资料,通过滑动相关分析,揭示了ENSO与中国夏季年际气候异常关系的年代际变化事实。结果表明:ENSO与中国夏季年际气候异常的关系既有稳定的方面,又存在年代际变化特征。稳定的关系表现在:处于发展阶段的ENSO事件往往造成华北夏季降水偏少;处于衰减阶段的ENSO事件则易引起长江流域及江南地区夏季降水偏多。而二者关系的年代际变化表现在:1970年代中后期,处于发展阶段的ENSO事件引起的夏季降水异常在华南地区由偏少变为偏多,东北地区则由偏多变为偏少,而江淮地区偏多的现象不再明显,华北和东北夏季气温异常也由偏冷转变为偏暖,而华南则有偏冷趋势;处于衰减阶段的ENSO事件引起的夏季降水异常在华北地区由偏多变为偏少,江淮地区降水由偏少变为正常甚至偏多,华北夏季气温异常则由偏冷变为偏暖,长江流域和华南也有偏暖趋势。利用NCEP/NCAR再分析资料合成分析表明,在不同的年代际背景下ENSO引起的东亚中高纬度大气环流异常型发生了明显改变是ENSO和降水气温关系发生年代际变化的原因。  相似文献   

11.
The spatio-temporal variations of eastern China spring rainfall are identified via empirical orthogonal function (EOF) analysis of rain-gauge (gridded) precipitation datasets for the period 1958–2013 (1920–2013). The interannual variations of the first two leading EOF modes are linked with the El Niño–Southern Oscillation (ENSO), with this linkage being modulated by the Pacific Decadal Oscillation (PDO). The EOF1 mode, characterized by predominant rainfall anomalies from the Yangtze River to North China (YNC), is more likely associated with out-of-phase PDO–ENSO events [i.e., El Niño during cold PDO (EN_CPDO) and La Niña during warm PDO (LN_WPDO)]. The sea surface temperature anomaly (SSTA) distributions of EN_CPDO (LN_WPDO) events induce a significant anomalous anticyclone (cyclone) over the western North Pacific stretching northward to the Korean Peninsula and southern Japan, resulting in anomalous southwesterlies (northeasterlies) prevailing over eastern China and above-normal (below-normal) rainfall over YNC. In contrast, EOF2 exhibits a dipole pattern with predominantly positive rainfall anomalies over southern China along with negative anomalies over YNC, which is more likely connected to in-phase PDO–ENSO events [i.e., El Niño during warm PDO (EN_WPDO) and La Niña during cold PDO (LN_CPDO)]. EN_WPDO (LN_CPDO) events force a southwest–northeast oriented dipole-like circulation pattern leading to significant anomalous southwesterlies (northeasterlies) and above-normal (below-normal) rainfall over southern China. Numerical experiments with the CAM5 model forced by the SSTA patterns of EN_WPDO and EN_CPDO events reproduce reasonably well the corresponding anomalous atmospheric circulation patterns and spring rainfall modes over eastern China, validating the related mechanisms.  相似文献   

12.
Interdecadal variation of the relationships between ENSO and the summer interannual climate variability in China is investigated by using techniques of sliding correlation analysis with the tropical Pacific SSTA and the observed surface air temperature and precipitation from stations in China. The results indicate that there are stable and robust relations that the Northern China is relatively dry during the developing phase of ENSO while the Yangtze River valley is relatively wet during the decaying phase of ENSO. On the other hand, interdecadal variations of the relations are also found in other regions. Over the time both prior to the Pacific decadal climate shift (before the late 1970s) and after it (after the late 1970s), during the developing phases of ENSO the summer precipitation anomaly in South China changed from below to above normal, whereas that in Northeast China changed from above to below normal; the summer surface air temperature anomaly in North and Northeast China changed from cooling to warming, whereas that in South China changed to cooling; during the decaying phases of ENSO the North China changed from wetter to dryer while the Huai River valley changed from dryer to normal; North China, Yangtze River valley and South China tend to be warmer. Based on the composite analysis of the NCAR/NCEP reanalyze datasets, significant differences existing in ENSO-related atmospheric circulation anomaly in East Asia during pre- and post-shift periods may be responsible for the interdecadal variation of relationships between ENSO and surface air temperature and precipitation in China.  相似文献   

13.
Forecasting grain production is of strategic importance in considerations of climate change and growing population. Here we show that the springtime North Atlantic Oscillation (NAO) is significantly correlated to the year-to-year increment of maize and rice yield in Northeast China (NEC). The physical mechanism for this relationship was investigated. Springtime NAO can induce sea surface temperature anomalies (SSTAs) in the North Atlantic, which display a tripole pattern and are similar to the empirical mode pattern in spring. The spring Atlantic SSTA pattern that could persists to summer, can trigger a high-level tropospheric Rossby wave response in the Eurasia continent, resulting in atmospheric circulation anomalies over the Siberia-Mongolia region, which is unfavorable (favorable) for cold surges that affect NEC. Weaker (stronger) cold surges can accordingly reduce (increase) cloud amount, resulting in an increase (a decrease) in daily maximum temperature and a decrease (an increase) in daily minimum temperature, thereby leading to an increase (a decrease) in diurnal temperature range. And summer-mean daily minimum temperature and diurnal temperature range are most significantly related to the NEC crop yields.  相似文献   

14.
近百年中国气候经历了两次明显的年代际变暖,分别发生在20世纪40年代之前和70年代之后。由大气环流变化引起的冷、暖平流异常可为理解两次变暖提供参考。首先基于最新研制的近百年32站气温观测和集合经验模分解(Ensemble Empirical Mode Decomposition,EEMD)方法揭示两次变暖过程中国的冷、暖分布格局,进而利用全球格点气温和海平面气压资料计算了同期地转风导致的温度平流。结果表明,20世纪40年代中国华北北部至东北大部分地区和华南沿海局部地区偏冷而中东部至西南内陆大部分地区偏暖的年代际气候异常,站点冷、暖异常与大尺度温度平流的空间关联系数达0.85;而对于近20年中国气候变暖而言,这一关联系数仅0.49。研究结果从一个新颖的角度说明:早期变暖过程中气候系统内部过程如大气环流异常的作用较大,而近几十年气候变暖则更多地受迫于外强迫。   相似文献   

15.
1 INTRODUCTION Chilling damage, flooding and drought in summer are the major climatic disasters inNortheast China. Before the 1980s chilling damage often occurred, and after 1990s flooding and drought disasters were more noticeable in this region. These c…  相似文献   

16.
中国东部夏季分区降水对海温异常响应特征的研究   总被引:6,自引:5,他引:1  
用刘征宇最新发展的广义平衡反馈方法结合经验正交分析和旋转经验正交分析法,研究中国东部6个分区夏季降水异常对各海盆海温异常(SSTA)模态的响应特征,探讨了东北区降水异常对SSTA的响应机制。结果表明:各分区降水异常对SSTA的响应特征有明显差异。东北区降水异常对热带太平洋SSTA的回应显著,当SSTA表现为类似El Niño模时,该区夏季降水增加;江淮区降水异常同时受到中纬度以及热带SSTA的强迫,对热带太平洋SSTA的类似La Niña Modoki模、北大西洋SSTA三极型模等回应显著;西南地区的降水异常主要与中纬度SSTA有密切关联。对流层高度场对热带太平洋SSTA类似El Niño模的直接回应在热带太平洋上空为显著正异常。通过东亚—太平洋型遥相关波列使东北地区上空高度场出现负异常,并在其西侧形成负异常中心,对流层低层为气旋性环流异常。这一环流回应与东北地区夏季降水偏多时的环流特征相近。  相似文献   

17.
中国东北南部冬季气温异常及其大气环流特征变化   总被引:9,自引:3,他引:9       下载免费PDF全文
该文在对东北冬季气温异常的时空变化特征进行分析的基础之上,利用NCEP/NCAR再分析资料,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。发现:东北冬季气温20世纪80年代中期以前处于冷期,60年代达到低谷,80年代中期以后一直处于暖期,90年代为49年来最暖期,1986年是由冷转暖的明显突变点;气温异常存在3~4年、8~9年的年际周期及16~18年的年代际周期;东北地区冬季气温异常与黄河以北地区一致性非常好,是49年全国增暖最显著的地区之一;冷、暖冬年,欧亚中高纬度大气环流异常存在显著的差异,西伯利亚高压、亚洲极涡、贝加尔湖高压脊、东亚大槽及极锋急流是影响其异常的同期重要因子。  相似文献   

18.
周连童  黄荣辉 《大气科学》2008,32(6):1276-1288
利用1951~2000年我国西北干旱、 半干旱区地温、 气温和表面风场逐日4个时次 (02、 08、 14和20时) 的台站观测资料, 计算并分析了我国西北干旱、 半干旱区春、 夏季感热的年代际变化特征。分析结果表明: 中国西北干旱、 半干旱区春、 夏季感热输送出现相反的年代际变化特征, 春季感热从20世纪70年代中期开始增强, 而夏季感热却减弱了。并且还分析了中国西北干旱、 半干旱区4月感热与中国夏季降水的相关关系, 其结果表明了中国西北干旱、 半干旱区的春季感热输送与中国夏季降水有很好的相关关系, 其中正相关区分别位于东北地区和长江中下游地区, 而负相关区分别位于华北地区和西南地区。作者还利用欧洲中心 (ECMWF) 1958~2000年再分析资料分析水平和垂直环流的年代际变化特征, 在1977~2000年期间, 中国西北地区春季感热增强, 使此地区上升气流增强, 华北地区上空下沉气流增强, 不利于华北地区夏季降水偏多, 并出现持续性干旱, 而长江流域的上升气流增强有利于长江中下游地区夏季降水增多, 出现洪涝。因此, 西北地区春季感热异常可以作为我国夏季降水的一个预报因子。  相似文献   

19.
This study investigates the interannual variation of summer surface air temperature over Northeast Asia(NEA) and its associated circulation anomalies.Two leading modes for the temperature variability over NEA are obtained by EOF analysis.The first EOF mode is characterized by a homogeneous temperature anomaly over NEA and therefore is called the NEA mode.This anomaly extends from southeast of Lake Baikal to Japan,with a central area in Northeast China.The second EOF mode is characterized by a seesaw pattern,showing a contrasting distribution between East Asia(specifically including the Changbai Mountains in Northeast China,Korea,and Japan) and north of this region.This mode is named the East Asia(EA) mode.Both modes contribute equivalently to the temperature variability in EA.The two leading modes are associated with different circulation anomalies.A warm NEA mode is associated with a positive geopotential height anomaly over NEA and thus a weakened upper-tropospheric westerly jet.On the other hand,a warm EA mode is related to a positive height anomaly over EA and a northward displaced jet.In addition,the NEA mode tends to be related to the Eurasian teleconnection pattern,while the EA mode is associated with the East Asia-Pacific/PacificJapan pattern.  相似文献   

20.
利用1951—2008年中国东北地区气温资料和NCEP高度场再分析资料,通过线性趋势分析和M-K检验方法,对东北地区冬季气温变化进行研究。结果表明:东北地区冬季变暖的时间是从20世纪80年代中期开始,突变年为1986年;冬季气温最暖年代出现在21世纪初;东北三省冬季累年气温变化趋势倾向基本是纬度越高气温趋势倾向值越大,特别是在1999—2008年黑龙江省冬季气温趋势倾向增温最显著。而在年气温变化趋势中,东北三省平均趋势倾向值没有冬季趋势倾向值大,其中吉林省气温趋势值最大。冷、暖冬年500 hPa高度距平场分布为冷冬负距平中心位于中国东北地区中部;暖冬年正距平中心位于贝加尔湖到中国东北地区中北部。低空冷冬年,东北地区受西北风、西风和东北风控制,冷空气势力强;暖冬年,东北地区仅受西北风影响,冷空气势力弱。  相似文献   

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