共查询到20条相似文献，搜索用时 46 毫秒
1.
本文首先分析了东北冷涡的持续性活动特征，然后讨论了东亚大气10～20天低频振荡及瞬变扰动对东北冷涡持续活动的影响。结果表明，准双周振荡在我国东北地区十分活跃，从时间连续的低频天气图上发现，该地区附近周期性循环出现的低频气旋同东北冷涡的形成和发展关系密切，并且其传播路径也较有规律。另外，本文还通过→E矢量分析以及月平均准地转位涡的收支计算，研究了东亚大气瞬变扰动对形成时间平均冷涡的影响，得出，在时间平均东亚阻高／东北冷涡偶极子系统控制的区域附近有瞬变扰动动能向时间平均气流动能转换，同时这里也存在有明显的→E矢量辐合，导致平均西风减弱，而有利于经向环流的发展。时间平均气流的位涡平流不利于阻高／冷涡偶极子系统的存在，且使偶极子系统高、低压中心的经向距离拉大，而瞬变扰动的位涡输送则有利于冷涡高位涡值和阻高低位涡值在原地维持，阻止它们向下游传播。 相似文献
2.
一次东北冷涡发展过程中的能量学研究 总被引：10，自引：2，他引：8
对一次典型的东北冷涡过程做了能量学分析。结果表明,东北冷涡活动具有鲜明的阶段性能量学特征。东北冷涡发展之前,各种能量之间的转换很小,边界通量也处于正负相间的振荡状态。早期发展阶段,扰动动能边界通量作用是至关重要的。随着非绝热加热制造扰动有效位能和扰动有效位能向扰动动能转换的大幅度增长,以及外界扰动动能的大量输送和纬向平均动能向扰动动能转换的明显加强,导致了东北冷涡的强烈发展,即这一时期区域内部的能量过程也同样十分重要。东北冷涡的减弱是从有大量扰动动能转换成纬向平均动能开始的,随后加上扰动有效位能向扰动动能转换以及边界通量作用的减弱,使得冷涡逐渐衰亡。 相似文献
3.
北半球风暴轴附近的能量转换 总被引：3，自引：3，他引：3
用１９８０￣１９８４年的ＥＣＭＷＦ客观分析资料，对任选一年的任意月份、正常年和尼尔尼诺年的特别月份天气尺度涡动能量及其与时间平均气流之间的能量转换项进行了分析。结果表明：在风暴轴区域，天气尺度涡动动能和天气尺度涡动有效位能最大，天气尺度涡动与时间平均气流之间的能量转换也是最剧烈；在风暴轴的入口区、出口区，天气尺度涡动与时间平均气流之间的能量转换是反向的，从而使风暴轴维持在比较常定的区域。 相似文献
4.
东海地区温带气旋爆发性发展的动力学分析 总被引：13，自引：8，他引：13
本文对东海地区两个气旋波的爆发性发展过程进行了动力学分析。结果表明:明显的对流层中下部增温、增温以及不稳定的大气层结和强高空西风急流,及其有关的次级环流的作用是气旋爆发性发展的重要条件。在气旋爆发性发展过程中,上升运动、正涡度以及高空辐散和低空辐合的散度场皆达到最强。加热场的计算也表明非绝热加热特别是凝结潜热释放也在气旋爆发时刻达到最强,最大加热区位于气旋的东北象限内。这时涡动动能的增加十分显著,它主要是由涡动有效位能向涡动动能的转换造成,这说明气旋的爆发性发展是与斜压发展密切有关。 相似文献
5.
采用常规观测资料和NCEP1°×1°资料,对山东半岛2005年、2008年、2010年的几次典型冷流暴雪过程进行了分析。分析结果表明：冷流暴雪的高空形势主要分为高空冷涡型和高空横槽型。高空冷涡型较高空横槽型降雪量偏大,暴雪站点多。高空冷涡型500hPa层以上的位涡值较高空横槽型偏大,高层位涡有利于低层正涡度的加强,促使低层产生低压环流及辐合上升运动,上升运动加强了海面水汽的垂直输送,故高空冷涡型上升速度较高空横槽型强,湿层较厚,高空冷涡型较高空横槽型更容易产生暴雪过程。 相似文献
6.
采用常规观测资料和NECP1o×1o资料,对山东半岛2005年、2008年、2010年的几次典型冷流暴雪过程进行了分析。分析结果表明：冷流暴雪的高空形势主要分为高空冷涡型和高空横槽型。高空冷涡型较高空横槽型降雪量偏大,暴雪站点多。高空冷涡型500hPa层以上的位涡值较高空横槽型偏大,高层位涡有利于低层正涡度的加强,促使低层产生低压环流,产生辐合上升运动, 上升速度加强了海面水汽的抬升,故高空冷涡型上升速度较高空横槽型强,相对湿度大值区面积较大,高空冷涡型较高空横槽型更容易产生暴雪过程。 相似文献
7.
一次台风变性并入东北冷涡过程的动力诊断分析 总被引：1，自引：0，他引：1
台风北移变性并入东北冷涡是造成东北地区夏季大范围暴雨的主要形式之一, 但其中的热动力结构变化特征及其物理机制尚不清晰。本文利用美国国家环境预报中心(NCEP)的再分析资料对一次台风变性并入东北冷涡过程进行动力诊断分析, 分析结果显示:冷涡冷空气的不断侵入以及台风移动形成的相对冷平流使得台风暖心结构消亡, 其低层低压辐合和高层高压辐散结构消失, 变性并入东北冷涡后气旋整层偏冷, 低层出现冷中心。台风变性并入东北冷涡过程中, 冷涡中心附近高空急流南侧的反气旋切变抑制气旋直接往高空发展, 而急流轴左侧的热动力分布特征有利于垂直涡度的发展, 变性后的气旋环流向冷涡的移近有利于急流轴维持倾斜, 从而促进气旋向高空冷涡倾斜发展。同时, 冷空气在气旋低层附近堆积导致等假相当位温线发生倾斜, 造成垂直涡度在气旋中层倾斜发展。台风变性并入东北冷涡后, 高空冷涡槽底的正垂直涡度平流促进气旋由中层直接向高层发展, 而高空冷涡槽底急流促进正垂直涡度平流的维持。气旋高空环流的发展反过来削弱了东北冷涡的高层环流, 导致高空冷涡中心出现北撤。 相似文献
8.
利用常规天气、地面危险天气报、自动站加密、NCEP/NCAR再分析资料等,对2011年7月12—20日持续9 d的华北冷涡过程阶段性特征进行分析。结果表明:冷涡过程降水主要分布在内蒙古东北部、华北和东北南部,发展阶段对流性强,多雷暴大风和冰雹,水汽来源于西南和东南气流,850 hPa上有强暖温度脊,高空急流较完整;减弱阶段以短时强降水为主,水汽来源于偏东气流;两阶段700 hPa以下为斜压,上升运动区主要位于东侧;发展阶段500 hPa为干区,南侧存在干空气侵入和θe梯度;减弱阶段整层相对湿度较大,θe锋区及不稳定度减弱。中层冷平流及中高层正涡度平流随高度增强是冷涡发展的主要因子,冷涡减弱是由低层冷平流进入冷涡中心、中层冷平流及中高层正涡度平流减弱共同影响所致。 相似文献
9.
10.
东北冷涡加强减弱过程的涡度收支和支能诊断 总被引：1，自引：0，他引：1
对东北冷涡加强和减弱阶段的涡度和动能的收支进行诊断分析。结果表明：无论在加强还是减弱阶段,冷涡区域范围整层的涡度变化均很明显;涡度平衡方程中,散度项,水平平流项及余项均是主要项,正涡度的增长和减弱对冷涡加强和减弱有重要贡献;动能收支方程中的各项也有明显差异,且在对流层中上层均有较强的能量交换过程。 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.
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
13.
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
14.
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
15.
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
16.
《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
17.
《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
18.
19.
《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
20.
DING Yihui WU Guoxiong Da-Lin ZHANG ZHANG Renhe Co-Chief Editors 《Acta Meteorologica Sinica》2014,28(5):669-670
As we will soon celebrate the 90th anniversary of the founding of the Chinese Meteorological Society （CMS）,Acta Meteorologica Sinica （AMS）,which was originally named as Bulletin of the Chinese Meteorological Society,has gone through 89 years of development and excitement since her first issue in July 1925.According to archived documents （CMS Editorial Committee,1925）,AMS was founded to report the research findings of Chinese meteorologists,record their recommendations for improving meteorological services,and share their common meteorological interests in order to promote the growth of AMS such that more members could be inspired to conduct atmospheric research and meteorological knowledge would be better disseminated to and benefit the general public.By upholding and carrying forward this purpose,AMS has published many highly valuable scientific papers.Some could be treated as classical articles,which have produced important influences on both domestic and international meteorological communities and the related fields. 相似文献