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1.
《气象》2017,(汛)
本文利用站点数据、再分析数据,采用经验正交函数分解(EOF)、合成分析等统计方法,探讨了2015年汛期(4—9月)内我国南方逐候降水的空间模态及其对应的环流特征。结果表明:2015年汛期,南方地区汛期总体表现为东西反向降水型,体现了强El Nino发展年的一般特征,但进一步分析发现汛期内候尺度东西反向降水型具有多样性特征。对候尺度降水资料EOF展开后的第一模态(EOF1)和第三模态(EOF3)为两类东西反相型降水,在对流层高、中、低层都有明显的差异。EOF1东多西少(A1)型是由低层菲律宾反气旋主导的降水型,副热带高压偏强西伸显著,南亚高压偏强偏东,我国南方东部的大部分地区降水偏多。而EOF3的东多西少(A2)型是由热带气旋活动主导的降水型,南海北部为气旋式环流;副热带高压偏强,相对于A1型偏东;南亚高压较常年同期偏强、偏东,东南沿海降水偏多。EOF1的东少西多(B1)型明显受到南下冷空气活动的影响,副热带高压偏强,位置相对偏东,印缅槽增强,有利于南方西部降水偏多。而EOF3的东少西多(B2)型是菲律宾反气旋位置异常主导的结果,副热带高压明显偏强偏西,引导水汽到南方西部地区。2015年汛期内东西反相旱涝型与菲律宾反气旋活动及位置、热带气旋活动及位置、冷空气活动路径有密切的关系,受到多种环流配置的影响。 相似文献
2.
利用NCAR/NCEP月平均再分析资料,探讨夏季西太平洋副热带高压异常时东亚热带季风、梅雨锋及中高纬环流的变化特征.研究表明:夏季西太平洋副热带高压脊线异常偏南或脊点异常偏西时,东亚夏季风环流偏弱,850 hPa矢量风距平场上东亚热带地区出现反气旋性环流,副热带地区呈气旋性环流,500 hPa垂直速度距平场上东亚热带地区上升运动减弱,梅雨锋区上升运动加强,500 hPa高度上东亚高纬鄂霍次克海区域出现阻塞高压,高纬冷空气直达中纬度,梅雨锋扰动加强,造成江淮流域汛期降水偏多.夏季西太平洋副热带高压脊线异常偏北或脊点异常偏东时,东亚夏季风环流偏强,东亚大气环流系统的活动出现了与上述情况相反的异常型,江淮流域汛期降水偏少. 相似文献
3.
使用1951—2013年NOAA OLR、NCEP/NCAR风场和高度场再分析资料、中国气象局热带气旋资料,分析2013年影响广西热带气旋数量偏多的原因。结果表明：2013年6—9月西太平洋副热带高压明显偏强,西伸脊点明显偏西,脊线略偏北,同时副热带高压南侧对流活跃,降水过程潜热释放有助于副热带高压位置偏北,这种形势非常有利于热带气旋向广西移动。索马里越赤道气流强劲,在南海及菲律宾与北太平洋反气旋西南侧的东南气流相遇,形成季风槽,非常有利于热带气旋生成频数偏多。热带低频强对流带在印度洋和西太平洋活动频繁,并分别向东向西移动;赤道东太平洋海温偏低;哈得来和沃克环流较常年偏强,沃克环流上升支位置偏西,这些也可能是2013年影响广西热带气旋数量偏多的原因之一。 相似文献
4.
利用5月份澳大利亚海平面气压和中国107站的6—7月降水资料,使用SVD方法揭示了5月份澳大利亚高压(简称澳高)与江苏汛期(6—7月)降水(简称汛期降水)的联系及可能原因,研究表明:当5月澳高偏强时,汛期环流特征表现为:(1)低层风场在30°N附近存在明显的风向切变,上升气流显著,并且西太平洋副热带高压较常年偏西,这样有利于降水增多;(2)130°E附近的越赤道气流显著加强,为降水提供了很好的水汽条件。主要影响途径:当5月澳高偏强(偏弱)时,与澳高相联系的印度尼西亚附近海温持续性偏冷(偏暖),偏冷(偏暖)的海温一方面使得其区域低层风场的异常辐散(辐合),异常辐散(辐合)风场作为涡度源通过Gill型响应可引起西太平洋异常反气旋(气旋)环流,有利于副热带高压较常年偏强偏西(偏弱偏东),也增强(减弱)了自南向北的暖湿气流的输送;另一方面引起其区域下沉(上升)气流异常,进而通过类似与EAP波列,激发江淮地区的异常上升(下沉)气流,使得汛期降水偏多(偏少)。 相似文献
5.
揭示热带气旋在湖南的降水规律可为热带气旋影响湖南的降水预报提供技术支撑。采用近67 a的热带气旋影响资料,通过统计方法,分析了影响湖南降水的热带气旋特点及环流异常特征。结果表明:7—9月是影响的高峰季节,以在广东、福建沿海登陆的热带气旋对湖南影响次数最多、程度最重,浙江、福建沿海登陆的热带气旋在湖南形成的降水范围最大,热带气旋对湖南影响所产生的降水主要集中在湖南省东南部,热带气旋对湖南产生的强降水范围有增大的趋势,降水强度有增强的趋势。福建和广东沿海登陆对湖南影响的热带气旋的环流特征为南亚高压偏强、偏东、偏北,导致西太平洋副热带高压偏强、偏西、偏北,引导副热带高压南侧的东南气流与南海和菲律宾以东洋面的西南风气流汇合,形成季风槽,中国华南和华东沿海为东南气流,有利于热带气旋在该区域登陆影响中国。只是前者表现为南亚高压位置较后者偏北更明显,西太平洋副热带高压更偏北,季风槽更偏东,导致福建登陆对湖南影响的热带气旋在湖南大部为气旋性环流控制,湖南全省降水偏多;而广东登陆对湖南影响的热带气旋在湖南省东南部为气旋性环流控制,该区域降水偏多。 相似文献
6.
副热带东南太平洋海温对东北夏季降水的影响及可能机制 总被引：1，自引：0，他引：1
诊断分析表明,前期副热带东南太平洋海温尤其是前春海温与东北夏季降水存在持续稳定的负相关关系。无论是在年际时间尺度还是年代际尺度上,冬、春、夏季海温演变趋势与降水均呈反位相。尺度分离结果显示,关键区海温与降水的显著负相关主要依赖于其年代际分量,但年际分量也起到较重要贡献。相关分析和合成分析结果都发现,当副热带东南太平洋海温偏低时,其上空可激发出反气旋式距平风场,而在关键区海域西北部激发出气旋式距平环流。同时在所罗门群岛和菲律宾南部分别出现反气旋式和气旋式距平环流。西太平洋副热带高压(副高)位置较常年偏西,副高区为反气旋式距平环流。在东北地区西侧则为气旋式距平环流。在这样的环流背景下,副高西侧的南风加强了源自南海和西太平洋的暖湿气流和北方冷空气在东北地区的交汇,从而使东北夏季多雨。反之,当东南太平洋海温偏高时,其激发的气旋及反气旋距平中心和偏低年刚好相反,副高位置偏东,其西侧的南方水汽输送偏弱,同时东北冷涡也偏弱,冷暖空气汇合形成的低空辐合弱,东北降水因此偏少。这表明,副热带东南太平洋海温异常时确实能激发出一个从关键海区到东北地区的跨越南北半球的气旋-反气旋交替波列,引发北半球中高纬度大气环流异常,从而影响东北夏季降水。 相似文献
7.
《气象》2021,(4)
2020年汛期准确预测了"我国气候状况总体偏差,极端天气气候事件偏多""涝重于旱"的总体特征,对长江中下游、黄河中上游、海河流域以及松花江流域降水较常年同期偏多和辽河流域降水偏少的预测与实况吻合。较好把握了华南前汛期雨季开始偏早、梅雨开始偏早和结束偏晚、华北雨季开始偏晚等雨季进程;但低估了长江中下游降水偏多的异常程度,对江淮西部、汉水降水明显偏多预测不准确,对四川盆地降水异常偏多也估计不足。对全国气温偏高以及我国南方高温日数偏多等主要趋势特征的预测与实况一致,对汛期台风数量较常年偏少及前期生成偏少后期生成偏多,以及在夏末至秋季较常年同期活跃的变化趋势的预测也均与实况吻合。2020年汛期预测重点考虑了前冬赤道中东太平洋弱暖水衰减的演变趋势对东亚夏季环流的滞后影响,同时热带印度洋的持续暖海温的接力作用有利于西太平洋副热带高压持续偏强偏西、菲律宾异常反气旋偏强。预测中低估了热带印度洋的异常偏暖程度及其对长江中下游、江淮地区降水的影响,导致预测中出现了较大偏差。国家气候中心模式对我国东部地区降水整体偏多的特征把握较好,这主要与模式对夏季平均的热带和副热带主要环流系统的空间分布型预测准确有关。但对季节内尺度的环流变化特征把握不好,包括中高纬欧亚地区在6—7月表现出的"两脊一槽"双阻型环流,以及7月副热带高压脊线位置持续偏南,季节进程较常年明显偏晚。 相似文献
8.
广州春季降水存在以准2年为主的年际变化和以30年为主的年代际变化，目前处于年代际尺度上的少雨时段。Nino3区的海温异常是广州春季降水最强的前兆信号，它与广州春季降水的显著正相关在前一年的11月份就已出现，并且一直稳定维持到4月份。前冬Nino3区海温异常对广州春季降水的影响是通过影响春季北太平洋副热带高压和低层风场异常实现的。前冬Nino3区海温正异常时，春季副热带高压偏强、位置偏西，华南处于副高边缘垂直运动的上升区，菲律宾以东的低层反气旋环流增加了向华南的水汽输送，从而使得广州春季降水偏多；前冬Nino3区海温负异常时，副热带高压偏弱、位置偏东，华南地区远离副高、处于垂直运动的下沉区，菲律宾以东低层为气旋环流控制，华南地区盛行偏北气流，不利于水汽的向北输送，从而使得广州春季降水偏少，造成春旱。 相似文献
9.
基于1986—2015年湖南逐日降水资料、同期美国气象环境预报中心(NCEP)和美国国家大气研究中心(NCAR)再分析资料,通过分析强低频振荡年的汛期强降水特征和低频环流场演变对强降水的影响,建立了湖南省汛期延伸期强降水过程预报指数。结果表明:(1)汛期33%的强降水过程均发生在具有显著30~60 d低频振荡的年份中,且大多位于低频降水峰值阶段。(2)通过对强低频振荡年进行合成发现,在活跃位相,南亚高压偏强偏东,副热带高压偏西偏强,这种环流配置导致中国南方大部分地区的高层环流为辐散,底层环流为辐合,有利于降水的产生。在中断位相,南亚高压呈东西带状分布且其位置偏西、强度偏弱,副热带高压偏东偏弱,使得向湖南地区输送水汽的西南气流减弱,进入降水中断期。(3)基于低频散度场不同位相的变化特征,选取了与低频降水相关的两个关键区,从而建立延伸期预报指数,该指数对低频降水显著年的强降水回报准确率能够达到73%。(4)前期4月黑潮的海温异常(SSTA)可作为湖南省强低频振荡年的预测指标。 相似文献
10.
2012年华南前汛期降水特征及环流异常分析 总被引：5，自引：1，他引：4
2012年华南前汛期于4月第2候开始,6月第5候结束。前汛期降水经历了三个不同的阶段：第一阶段是4月第2候至5月第3候的降水集中期（锋面降水）,江南大部和华南大部降水偏多25％以上,第二阶段是5月第4候至6月第2候的少雨期,华南中部和东部降水偏少50％以上,第三阶段是6月第3—5候的第二个降水集中期（季风降水）,江南东南部至华南中西部降水偏多50％以上。对各阶段大气环流距平场的分析结果表明：华南前汛期开始后,偏强的乌拉尔山高压脊导致南下的冷空气偏强,偏强的低层副热带高压使得我国南方为整层水汽输送的异常辐合区,两者共同导致华南前汛期第一阶段的锋面降水较常年同期偏多;南海夏季风在爆发后偏弱和西北太平洋副热带高压（以下简称副高）持续3候异常偏北是导致第二阶段前汛期降水明显偏少的主要原因;第三阶段,南海夏季风异常偏强,副高南落并增强,以及孟加拉湾季风槽的偏强使得华南前汛期此阶段的季风降水偏多。 相似文献
11.
The spatial and temporal variations of daily maximum temperature(Tmax), daily minimum temperature(Tmin), daily maximum precipitation(Pmax) and daily maximum wind speed(WSmax) were examined in China using Mann-Kendall test and linear regression method. The results indicated that for China as a whole, Tmax, Tmin and Pmax had significant increasing trends at rates of 0.15℃ per decade, 0.45℃ per decade and 0.58 mm per decade,respectively, while WSmax had decreased significantly at 1.18 m·s~(-1) per decade during 1959—2014. In all regions of China, Tmin increased and WSmax decreased significantly. Spatially, Tmax increased significantly at most of the stations in South China(SC), northwestern North China(NC), northeastern Northeast China(NEC), eastern Northwest China(NWC) and eastern Southwest China(SWC), and the increasing trends were significant in NC, SC, NWC and SWC on the regional average. Tmin increased significantly at most of the stations in China, with notable increase in NEC, northern and southeastern NC and northwestern and eastern NWC. Pmax showed no significant trend at most of the stations in China, and on the regional average it decreased significantly in NC but increased in SC, NWC and the mid-lower Yangtze River valley(YR). WSmax decreased significantly at the vast majority of stations in China, with remarkable decrease in northern NC, northern and central YR, central and southern SC and in parts of central NEC and western NWC. With global climate change and rapidly economic development, China has become more vulnerable to climatic extremes and meteorological disasters, so more strategies of mitigation and/or adaptation of climatic extremes,such as environmentally-friendly and low-cost energy production systems and the enhancement of engineering defense measures are necessary for government and social publics. 相似文献
12.
Yuepeng PAN Mengna GU Yuexin HE Dianming WU Chunyan LIU Linlin SONG Shili TIAN Xuemei Lü Yang SUN Tao SONG Wendell W. WALTERS Xuejun LIU Nicholas A. MARTIN Qianqian ZHANG Yunting FANG Valerio FERRACCI Yuesi WANG 《大气科学进展》2020,37(9):933-938
正While China’s Air Pollution Prevention and Control Action Plan on particulate matter since 2013 has reduced sulfate significantly, aerosol ammonium nitrate remains high in East China. As the high nitrate abundances are strongly linked with ammonia, reducing ammonia emissions is becoming increasingly important to improve the air quality of China. Although satellite data provide evidence of substantial increases in atmospheric ammonia concentrations over major agricultural regions, long-term surface observation of ammonia concentrations are sparse. In addition, there is still no consensus on 相似文献
13.
Observed daily precipitation data from the National Meteorological Observatory in Hainan province and daily data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis-2 dataset from 1981 to 2014 are used to analyze the relationship between Hainan extreme heavy rainfall processes in autumn (referred to as EHRPs) and 10–30 d low-frequency circulation. Based on the key low-frequency signals and the NCEP Climate Forecast System Version 2 (CFSv2) model forecasting products, a dynamical-statistical method is established for the extended-range forecast of EHRPs. The results suggest that EHRPs have a close relationship with the 10–30 d low-frequency oscillation of 850 hPa zonal wind over Hainan Island and to its north, and that they basically occur during the trough phase of the low-frequency oscillation of zonal wind. The latitudinal propagation of the low-frequency wave train in the middle-high latitudes and the meridional propagation of the low-frequency wave train along the coast of East Asia contribute to the ‘north high (cold), south low (warm)’ pattern near Hainan Island, which results in the zonal wind over Hainan Island and to its north reaching its trough, consequently leading to EHRPs. Considering the link between low-frequency circulation and EHRPs, a low-frequency wave train index (LWTI) is defined and adopted to forecast EHRPs by using NCEP CFSv2 forecasting products. EHRPs are predicted to occur during peak phases of LWTI with value larger than 1 for three or more consecutive forecast days. Hindcast experiments for EHRPs in 2015–2016 indicate that EHRPs can be predicted 8–24 d in advance, with an average period of validity of 16.7 d. 相似文献
14.
Based on the measurements obtained at 64 national meteorological stations in the Beijing–Tianjin–Hebei (BTH) region between 1970 and 2013, the potential evapotranspiration (ET0) in this region was estimated using the Penman–Monteith equation and its sensitivity to maximum temperature (Tmax), minimum temperature (Tmin), wind speed (Vw), net radiation (Rn) and water vapor pressure (Pwv) was analyzed, respectively. The results are shown as follows. (1) The climatic elements in the BTH region underwent significant changes in the study period. Vw and Rn decreased significantly, whereas Tmin, Tmax and Pwv increased considerably. (2) In the BTH region, ET0 also exhibited a significant decreasing trend, and the sensitivity of ET0 to the climatic elements exhibited seasonal characteristics. Of all the climatic elements, ET0 was most sensitive to Pwv in the fall and winter and Rn in the spring and summer. On the annual scale, ET0 was most sensitive to Pwv, followed by Rn, Vw, Tmax and Tmin. In addition, the sensitivity coefficient of ET0 with respect to Pwv had a negative value for all the areas, indicating that increases in Pwv can prevent ET0 from increasing. (3) The sensitivity of ET0 to Tmin and Tmax was significantly lower than its sensitivity to other climatic elements. However, increases in temperature can lead to changes in Pwv and Rn. The temperature should be considered the key intrinsic climatic element that has caused the "evaporation paradox" phenomenon in the BTH region. 相似文献
15.
Storms that occur at the Bay of Bengal (BoB) are of a bimodal pattern, which is different from that of the other sea areas. By using the NCEP, SST and JTWC data, the causes of the bimodal pattern storm activity of the BoB are diagnosed and analyzed in this paper. The result shows that the seasonal variation of general atmosphere circulation in East Asia has a regulating and controlling impact on the BoB storm activity, and the “bimodal period” of the storm activity corresponds exactly to the seasonal conversion period of atmospheric circulation. The minor wind speed of shear spring and autumn contributed to the storm, which was a crucial factor for the generation and occurrence of the “bimodal pattern” storm activity in the BoB. The analysis on sea surface temperature (SST) shows that the SSTs of all the year around in the BoB area meet the conditions required for the generation of tropical cyclones (TCs). However, the SSTs in the central area of the bay are higher than that of the surrounding areas in spring and autumn, which facilitates the occurrence of a “two-peak” storm activity pattern. The genesis potential index (GPI) quantifies and reflects the environmental conditions for the generation of the BoB storms. For GPI, the intense low-level vortex disturbance in the troposphere and high-humidity atmosphere are the sufficient conditions for storms, while large maximum wind velocity of the ground vortex radius and small vertical wind shear are the necessary conditions of storms. 相似文献
16.
《大气和海洋科学快报》2013,(4):227
正AIMS AND SCOPE Atmospheric and Oceanic Science Letters (AOSL) publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. 相似文献
17.
《大气和海洋科学快报》2014,7(6):F0003-F0003
AIMS AND SCOPE
Atmospheric and Oceanic Science Letters （AOSL） publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. Contributions from all over the world are welcome. 相似文献
Atmospheric and Oceanic Science Letters （AOSL） publishes short research letters on all disciplines of the atmosphere sciences and physical oceanography. Contributions from all over the world are welcome. 相似文献
18.
《大气和海洋科学快报》2014,(5):F0003-F0003
AIMS AND SCOPE Atmospheric and Oceanic Science Letters （AOSL） pub- lishes short research letters on all disciplines of the atmos- phere sciences and physical oceanography. Contributions from all over the world are welcome. 相似文献
19.
20.
《大气科学进展》2014,(6)
正Aims Scope Advances in Atmospheric Sciences(AAS)is an international journal on the dynamics,physics,and chemistry of the atmosphere and ocean with papers across the full range of the atmospheric sciences,co-published bimonthly by Science Press and Springer.The journal includes Articles,Note and Correspondence,and Letters.Contributions from all over the world are welcome. 相似文献