共查询到20条相似文献，搜索用时 109 毫秒
1.
本文通过对两场过程的降水性质、成因、强对流天气特征等方面进行对比分析,初步得到以下结论:"8.14"大暴雨为副高后部冷涡背景下的强对流天气,局地性、突发性强,伴有强雷暴、短时强降水、大风、冰雹等强对流天气灾害;而"8.16"大暴雨为系统性的降水过程,主要影响系统为地面暖锋,影响范围更广、持续时间更长。两场强对流天气发生条件有显著差别。"8.14"过程为典型上干冷下暖湿结构;而"8.16"整层均为湿层,强对流天气主要以短时强降水为主。连续出现两场大暴雨天气,与高温高湿的天气背景密切相关。高、低空急流的配置起着决定性作用。高、低空急流交叠处形成较强的垂直风切变环境,是强风暴产生发展的有利条件,这两次大暴雨的落区均在急流交叠处下方。 相似文献
2.
利用NCEP 1°×1°再分析资料、FY-2G卫星云图、多普勒C波段天气雷达以及吉林省区域自动站和加密自动站资料,运用统计分析和天气动力学诊断方法,综合分析2016年7月25—26日吉林省暴雨天气过程,此次暴雨和大暴雨落区位于吉林省四平东部、辽源、吉林和通化北部,此次暴雨过程出现东北冷涡天气背景下,25日14—22时的短时强降水由东北冷涡前部局地对流活动的加强触发中尺度对流系统(MCS)生成。500 hPa为两脊一槽形势,受西太平洋副热带高压阻挡,东北冷涡较为稳定,吉林省位于东北冷涡前沿的西南气流中,850 hPa西太平洋副热带高压西侧的西南急流直达吉林省中南部,在其北端产生西南—东南向暖锋式切变,并与地面黄河气旋暖锋区相对应。在地面中尺度辐合线、地形抬升触发下,造成中尺度对流,形成短时强降水。通过FY-2G卫星相当黑体温度(TBB)产品分析,发现吉林省上空TBB低于-52℃时,就会产生短时强降水,而TBB高于-48℃则MCS趋于消失;此次强降水的新一代C波段天气雷达回波具有较明显的强回波低质心结构特征,降水效率较高,持续时间短,但达到短时强降水标准。卫星TBB产品和雷达监测可为以后吉林省东北冷涡暴雨定时、定点暴雨预警提供依据。 相似文献
3.
一次局地大暴雨的落区分析与预报 总被引：8，自引：1，他引：7
应用常规天气资料、地面加密自动站资料、FY-2C红外TBB资料和多普勒雷达资料,并引用中尺度对流复合体(MCC)β中尺度单元(MBE)移动概念模型,对2007年7月18日天津地区出现的强雷雨、局地大暴雨天气进行了分析。结果表明:局地大暴雨是在大范围的有利天气条件下产生的,降水具有明显的β中尺度强对流系统特征;强降水出现在"人"字型回波带的头部,落区位置与中气旋的位置相对应;从地面加密自动站资料也能很好地分析出强降水雨区的位置和移动方向。通过分析FY-2C红外TBB资料表明:强降水出现在MCC中冷云顶区的右后侧,且降水强度在MCC中出现强冷云顶区时达到最强。应用MCCβ中尺度单元(MBE)移动的概念模型,通过判断MBE的移动,可以很好地预报出强降水下一时刻的具体落区位置,从而为该地区强雷雨、局地大暴雨落区的短时临近预报提供一种新的方法。 相似文献
4.
太行山地形影响下的极端短时强降水分析 总被引：8，自引：6，他引：2
2015年8月2日午夜和2011年8月9日前半夜,在两种不同天气系统背景下太行山东麓都出现了小时雨量超过50 mm的极端短时强降水天气,两次过程都是雷暴先在太行山区触发加强,经过下山2 h先后在丘陵站平山和山前平原站石家庄市区产生极端短时强降水。利用常规探测资料、地面加密观测资料、石家庄SA多普勒天气雷达资料,对不同天气系统背景下太行山特殊地形影响的极端短时强降水成因进行分析。结果表明:偏东气流被南北向的太行山地形强迫抬升,且与下山雷暴出流形成中尺度辐合线触发新的雷暴,雷达回波呈现后向传播特征和列车效应造成局地极端短时强降水。太行山地形通过增强辐合上升运动、增大垂直风切变使雷暴下山加强。不同天气系统强迫下,太行山特殊地形对雷暴发展作用不同。在偏西气流引导下,暖区极端短时强降水由阵风锋触发,具有突发性、降水时间短、伴随风力大的特点,下山雷暴出流加快且与山前偏东风的辐合加强,陆续在丘陵区和山前平原触发对流与下山雷暴合并加强造成极端短时强降水;而在东北气流引导下,回流冷锋和阵风锋共同触发的极端短时强降水具有持续时间较长、降雨总量较大、伴随风力较小的特点,太行山东坡对东北冷湿回流有阻挡积聚作用,东北偏北来的雷暴出流边界西端在迎风坡上强迫抬升使雷暴触发并加强,东北气流遇山后发生气旋性偏转使雷暴出流转向东南下山,与平原的偏东风辐合加强,造成丘陵区和山前平原的总降雨时间更长、降雨总量更大。 相似文献
5.
一次中-β尺度局地大暴雨对流系统的雷达回波特征 总被引：5，自引：0，他引：5
利用新一代天气雷达产品对2006年6月18日永定一次中-β尺度大暴雨对流系统的雷达回波特征进行分析,探讨短时大暴雨的回波特征.结果表明:有利的大尺度环流、充足的水汽条件和较强的上升运动是产生强降水有利的天气背景.新一代天气雷达资料分析表明,强降水是由局地发展的对流回波加强合并产生的;中低层冷平流的入侵触发了强对流的产生,对流单体有明显的典型的液态强降水系统特征;逆风区及良好的垂直运动使对流单体发展加强,强降水区域尺度较大,与回波移向一致产生"列车效应",同时系统移动较慢,导致了强降水的持续. 相似文献
6.
2008年4月7日夜间,洛阳市出现了入春以来的首次区域性雷暴天气,栾川县出现局地大暴雨,12 h降水量达到96 mm.利用常规气象资料和乡镇雨量站、新一代多普勒雷达资料,分析了此次区域雷暴过程中伴随的局地大暴雨成因,结果表明:这次局地大暴雨是在强垂直温度梯度条件下,低涡系统的东移,致使涡前切变线移入不稳定能量区,诱使不稳定能量暴发而产生的强对流天气,涡前切变线是这次过程的触发机制;前期晴朗高温天气所积蓄的不稳定能量释放是导致强降水形成的有利条件;K指数、SI指数等对流指数对此次局地暴雨有很好的反映;对流触发后生成的中β尺度对流系统稳定维持在栾川且获得发展是造成强降水的主因;栾川特殊的山地地形(伏牛山脉)对降水有一定的增幅作用. 相似文献
7.
为提高对短时局地强降水系统演变的认识，探索短时强降水天气特征及成因，利用FY-4A气象卫星及天气雷达遥感产品，并借助地面及探空资料，对2019年7月27日冀南平原一次局地大暴雨过程进行中尺度时空演化特征分析。结果表明，本次过程是在副热带高压外围，受高空槽以及低层切变线影响生成的局地强降水天气。降水系统内的对流组织主要经历了“新生发展-合并加强-降水维持-移出消散”的演化过程。本次冀南平原地区大暴雨的成因主要包括：两个初期发展的对流系统的合并加强，前期外围对流活动提供了充沛的水汽环境，强对流系统形成了低层旋转、中层强辐合的中尺度垂直环流结构，各层辐合中心空间位置基本一致，有利于水汽供应并维持云中液滴的高效碰并增长。研究结果对冀南平原短时强对流天气的临近预报预警提供了科学依据。 相似文献
8.
局部大暴雨形成的机理与中尺度分析 总被引：6，自引：6，他引：0
利用常规气象观测资料、区域自动站加密观测资料、NCEP逐6 h的1°×1°的再分析资料和FY-2C卫星逐时TBB资料、多普勒雷达探测资料,对2012年7月7-8日河南商丘地区大暴雨天气过程形成机理和中尺度系统活动特征进行了研究.结果表明:500 hPa低槽与低层东西向切变线和低空急流相互配合、共同作用是此次大暴雨形成的大尺度环境条件。中尺度分析显示:多个中尺度雨团的活动形成了4个大暴雨中心,中尺度雨团与MαCS相伴,而MαCS是由多个MγCS和MβCS合并、加强的结果。这些MγCS和MβCS是由地面中尺度辐合线或辐合中心触发产生并发展,MαCS覆盖区下强降水回波的移动和发展与地面中度辐合系统对应较好,大暴雨出现在地面辐合系统形成后的1~2 h内;而暖平流导致的局地升温,是地面中尺度辐合系统形成的主要原因。TBB梯度与降水强度成正比,当▽TBB/0.5°E≥34℃,并且TBB≤-63℃时,将产生30mm·h~(-1)的强降水;当MCS发展成熟时强降水发生在中尺度对流云团TBB低值中心附近,当TBB在1 h内降低31℃以上时,1~2 h后该地将出现雨强为50 mm的短时强降水。因此,地面热力不均匀导致的局地升温是此次地面中尺度辐合系统生成的主要原因,而地面中尺度辐合系统的发生发展触发了中小尺度对流系统的发生发展,导致了局部大暴雨的产生。根据中小尺度对流云团的TBB强度及变幅,可提前1~2 h预报短时强降水。 相似文献
9.
在天气预报业务中,发生在西太平洋副热带高压控制下的短时强降水容易出现漏报。为加深对西太平洋副热带高压控制下湖南短时强降水的认识,探究其成因和触发机制,本文利用地面自动站、多普勒天气雷达观测资料及FY-2F云顶亮温、NCEP再分析资料等,针对2018年9月6日一次西太平洋副热带高压控制下的湖南短时强降水成因开展研究。结果表明:在强盛的西太平洋副热带高压脊区内,丰沛的水汽、较强的不稳定能量及一定的抬升条件可触发短时强降水天气。正午前,受弱冷空气侵入影响,低层切变配合地面中尺度辐合线引起近地面动力抬升,从而触发对流性降水;午后,受太阳辐射影响,地面气温达到对流触发温度,从而触发热对流。正涡度区及低层辐合区在降水发生后都向上延伸,有利于垂直上升运动的维持,但较典型汛期强降水过程的动力条件明显偏弱。环境风及其垂直风切变小,且雷暴单体移动缓慢,有利于强降水在同一地区长时间维持。 相似文献
10.
《干旱气象》2015,(4)
利用常规、非常规观测及NCEP再分析资料,对广西1次高空触发强对流(简称高架强对流)及2次地面触发强对流(简称地面强对流)天气过程进行诊断对比分析。结果表明:高架强对流云系TBB值高,造成小冰雹,而地面强对流云系TBB值低且梯度大,冷中心达200 K,产生大冰雹、局地龙卷等;大冰雹回波具有高悬强回波、弱回波区、中气旋、三体散射及高的VIL;由弓形回波造成的强降水、雷暴大风,其发生前强回波质心迅速下降;超级单体风暴造成的局地龙卷,其回波具有中气旋、弱回波区及强组合切变,0~3 km垂直风切变在强风暴减弱消失前1 h左右明显减弱;"120227"、"130323"、"130417"3次强对流发生在高空急流轴右侧辐散区、中低层急流汇合处,具有强的环境风垂直切变及上干下湿特征,且抬升触发系统分别为近垂直分布的中高层、整层、中低层辐合系统(槽、切变、锋面或辐合线);"130323"地面过程造成的强对流灾害天气最强,其层结不稳定性及抬升运动也最强。 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》2013,(1):67
正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.SUBMISSIONAll submitted 相似文献
17.
18.
<正>With the support of specialized funds for national science institutions,the Guangzhou Institute of Tropical and Marine Meteorology,China Meteorological Administration set up in October 2008 an experiment base for marine meteorology and a number of observation systems for the coastal boundary layer,air-sea flux,marine environmental elements,and basic meteorological elements at Bohe town,Maoming city,Guangdong province,in the northern part of the South China Sea. 相似文献
19.
《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
20.
《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