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东北冷涡特征及其关键区的计算机识别 总被引：5，自引：0，他引：5
根据东北冷涡的定义及其在等压面上高度的变化特征，利用计算机在等压面网格点高度上自动识别东北冷涡的中心经纬度、中心高度和半径，确定东北冷涡的位置、强度和面积。还给出了在任意形状关键区中自动识别是否存在冷涡的方法。业务应用的实践证明，该方法对东北冷涡特征的识别准确，简便可靠，对观测错误具有较强的识别、处理能力。 相似文献
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基于1967—2017年美国环境预报中心和国家大气研究中心(NCEP/NCAR)的逐日再分析资料及英国气象局哈德来中心(Hadley Centre)的海温资料,通过计算冬季东北冷涡结构的特征指数并利用经验正交函数分解等方法,研究了冬季东北冷涡的时空变化特征及其与环流和海温变化的联系。结果表明:(1)冬季东北冷涡具有显著的年际变化与年代际变化特征,各指数年际分量的方差贡献率较大;冷涡强度与经、纬度呈正相关,且经、纬度之间呈正相关;(2)年际尺度第一模态反映了冬季东北冷涡气候平均位置以南为正(负)异常而以北为负(正)异常的南北反位相变化特征,第二模态反映了冬季东北冷涡在气候平均位置附近强度一致增强(强弱)的变化特征,而年代际尺度主要反映在第一模态,即冬季东北冷涡在气候平均位置附近强度一致增强(强弱)的变化特征;(3)北大西洋涛动(North Atlantic Oscillation, NAO)和西大西洋遥相关型(Western Atlantic, WA)的位相转换可能与年代际尺度冬季东北冷涡的强度强弱变化有关。 相似文献
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本文利用美国国家环境预报中心(NCEP)提供的2000-2017年5-8月FNL全球再分析资料,结合东北冷涡的定义,对东北冷涡过程气候特征进行统计分析,结果表明:2000-2017年5-8月共有211个东北冷涡过程,其发生频次和冷涡日数均具有明显的年际变化;东北冷涡活动主要集中于44-53°N,122-129°E之间,黑龙江省西北部与内蒙古东部交界的大兴安岭南麓地区以及黑龙江省南部与吉林交界处为东北冷涡活动的密集区,冷涡中心位置呈现明显的季节变化;东北冷涡以单中心为主,多中心冷涡数量随中心个数的增加而显著减少,高频区出现在黑龙江省中南部。 相似文献
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利用NCEP/NCAR逐日再分析资料及由吉林省气象局科研所提供的东北冷涡日历表,以1951/1952—2008/2009年58 a冬季为代表,分析了东北冷涡对北太平洋风暴轴产生的影响及其可能原因。结果表明:1)冬季东北冷涡发生天数变化与北太平洋风暴轴强弱变化呈显著的负相关关系,即当东北冷涡发生天数偏多(偏少)时,北太平洋风暴轴强度减弱(增强)。2)通过Morlet小波交叉谱分析发现,冬季东北冷涡发生天数的年际变化与北太平风暴轴强度变化存在准3 a尺度上的相关关系。3)在冬季,当东北冷涡发生天数偏多时,从东亚到西北太平洋沿岸低层温度降低,低层冷空气位于副热带急流和北太平洋风暴轴上游,且经向上处于两者之间,加之冷平流的作用,给副热带急流与北太平洋风暴轴活动区域带来了正好相反的局地斜压性的改变:副热带急流区域斜压性增加,变得强而窄,位置南压;而北太平洋风暴轴区域斜压性减小,同时由于西北太平洋区域低层温度降低,使得有利于涡动形成的波源效应减弱,风暴轴强度减弱。当东北冷涡发生天数偏少时,则反之。 相似文献
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东北冷涡的特征、影响及其可能机制的研究 总被引：2，自引：0，他引：2
对东北冷涡的天气气候特征及其影响和可能机制进行了回顾与综述。关于东北冷涡的研究主要经历了三个阶段:天气学分析阶段、诊断分析和数值模拟阶段以及东北冷涡的气候效应研究阶段。为了研究东北冷涡的变化及其对我国天气气候的影响,定量表征东北冷涡是一项重要的基础性工作。提出可以利用计算机自动识别东北冷涡过程的持续时间、中心强度(高度场、温度场)及活动区域等特征参数,并由此建立冷涡综合指数,以便更加客观、全面地表征东北冷涡,有利于在实际工作中应用。 相似文献
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近50年东北冷涡异常特征及其与前汛期华南降水的关系分析 总被引：16，自引：11，他引：16
利用中国气象局国家气象信息中心提供的1951～2004年中国160站华南前汛期 (5～6月) 月平均降水、气温资料、欧洲中心提供的ERA-40再分析资料和Reynolds海温资料, 对东北冷涡与华南前汛期降水进行了统计分析, 定义了一个前汛期东北冷涡强度指数 (NECVI), 并研究了前汛期东北冷涡异常年同期东亚季风、西太平洋副高、对流层低层的垂直运动异常特征和前期全球海表温度 (SST) 的先兆信号, 结果表明: 前汛期东北冷涡强度与华南降水存在显著的正相关, 东北冷涡强年, 前期东亚冬季风偏弱, 同期东亚夏季风异常爆发提前且偏强, 西太平洋副高位置偏南, 华南地区低层上升运动发展, 降水偏多; 东北冷涡偏弱年, 前期东亚冬季风偏弱, 同期东亚夏季风爆发推迟且偏弱, 西太平洋副高位置偏北, 华南地区低层下沉运动发展, 降水偏少; 前汛期东北冷涡与前期中国近海海温存在显著的负相关关系, 前汛期东北冷涡异常强年, 前期对应着La Nia的成熟阶段或发展阶段, 而前汛期东北冷涡异常弱年则对应着El Nio的成熟阶段或发展阶段. 相似文献
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中国夏季东北冷涡强度的定量化分析 总被引：5，自引：2，他引：3
本文利用NCEP/NCAR发布的1981~2010年全球日平均再分析位势高度场资料对东北冷涡进行检索并提取其平均态, 在此基础上定义东北冷涡的偏离指数, 并探讨其对东北冷涡强度特征的描述。结果表明: (1) 东北冷涡500 hPa闭合中心位势高度的概率分布近似为高斯分布, 以其期望值提取的东北冷涡平均态具有东北冷涡的共性, 表现出明显的大气斜压性及有利于系统维持和发展的温压配置关系特征; (2) 基于东北冷涡平均态定义的东北冷涡偏离指数不仅能够表征东北冷涡偏离平均态的程度, 还包含了低压面积的信息, 即能够直观地显示东北冷涡的强弱特征。 相似文献
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在数值预报产品诊断分析的基础上，计算东北冷涡强度的加强和减弱与物理量，温压场同时刻的相关关系，采用逐步判别方法，制作未来２４小时，４８小时冷涡强度变化的完全预报方程。检验结果表明，该方程对东北冷涡短期强度变化有较强的预报能力，可为客观预报提供依据。 相似文献
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一次东北冷涡产生的突发性暴雨分析 总被引：1，自引：0，他引：1
用常规天气图、云图及单站探空资料，对１９９６年７月６日夜间到７日凌晨生成于渤海的由东北冷涡引发的强对流单体的环境条件进行了诊断分析。结果表明：这个强对流单体产生于东北冷涡南部，地面弱冷锋附近，产生前，环境大气已处于对流不稳定状态，东北冷涡的南压和移动方向，冷涡横槽的转竖，山东半岛北海岸的对流不稳定环境及大量不稳定能量的贮藏，有利于强对流单体在山东半岛北海岸的发展和加强。 相似文献
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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
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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
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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
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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
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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
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《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
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《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
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《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
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《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