共查询到20条相似文献，搜索用时 46 毫秒
1.
2.
“20090719”致灾冰雹的多普勒雷达回波特征分析 总被引：1，自引：0，他引：1
利用石河子c波段多普勒天气雷达资料,结合常规观测资料对2009年7月19日傍晚发生在准噶尔盆地南缘沙漠边缘下野地地区的冰雹等强对流风暴的多普勒雷达回波演变特征进行了详细分析。结果表明:该强对流风暴具有超级单体风暴的典型特征,强风暴前进方向的右侧出现钩状回波,西北侧呈现出倒V字型缺口;沿入流方向穿过最强回波位置的反射率因子垂直剖面呈现出有界弱回波区、回波悬垂和有界弱回波区左侧的回波墙,最大回波强度出现在沿着回波墙的一个竖直的狭长区域,其值达到65dBz,垂直累积液态水含量达到65kg/m2。相应的径向速度图上出现中气旋,中气旋所对应的钩状回波反射率因子从低层往高层明显向低层入流一侧倾斜。回波顶高和垂直累积液态水含量的明显跃增及弱回波区和有界弱回波区的形成,为预测冰雹出现的时间和落区提供了一定的参考依据。弱回波区的出现超前冰雹发生近40分钟,对冰雹的预警、人工影响天气消雹具有较强的指示意义。 相似文献
3.
利用石河子c波段多普勒天气雷达资料,对2007年7月3日下午发生在石河子垦区南部山脉与平原交界区151团的冰雹等强对流风暴的多普勒雷达回波演变特征进行详细分析。结果表明：该强对流风暴具有超级单体风暴的典型特征,强风暴前进方向的右侧出现钩状回波,西北侧呈现出“V”字型缺口;反射率因子垂直剖面呈现出弱回波区、回波悬垂和弱回波区左侧的回波墙,最大回波强度超过65 dBz,垂直累积液态水含量超过70 kg/m2;相应的径向速度图上出现中气旋。该超级单体的移动方向在盛行风向的右侧约30°,属于右移风暴。 相似文献
4.
黔东南2012年4月10日大冰雹天气过程雷达回波特征分析 总被引：1，自引：0，他引：1
利用三穗新一代多普勒天气雷达对2012年4月10日发生在贵州省黔东南州的大冰雹天气过程进行跟踪探测,揭示了冰雹云形成发展、成熟和消散过程的主要回波特征。结果表明,强对流天气过程由多个对流单体组成,强回波区的反射率因子超过65 dBz,三体散射长钉的反射率因子最大值为21 dBz,最大长度20 km;径向速度有风暴顶辐散特征和逆风区存在,逆风区存在对大冰雹的出现有很好的指示作用;垂直累积液态水含量出现跃增现象,最大垂直累积液态水含量为56 kg.m-2;垂直风廓线中风向、风速出现较大垂直切变。 相似文献
5.
《气象》2021,(4)
利用常规观测、地面加密自动站、多普勒天气雷达、NCEP(1°×1°)逐6 h再分析资料对2017年8月23日云南中部地区一次强对流风暴的环境参数和雷达回波特征进行分析,结果表明:此次强对流风暴发生在台风低压前侧、中高纬冷槽后部的强不稳定层结背景下,地面辐合线和强垂直风切变有利于对流风暴的维持和加强。强对流风暴受地形影响较为明显,共激发形成6个超级单体或类超级单体,在超级单体发展成熟前10 min,3个降雹超级单体强中心沿地形爬升,未降雹和小雹超级单体沿地形下降。6个超级单体或类超级单体呈现出中气旋或γ中尺度弱涡旋特征,最大速度对转动值超过10 m·s~(-1)时出现不同程度冰雹,冰雹直径15 mm的超级单体在2.4°～3.4°仰角上径向速度值达到中气旋标准,冰雹直径为15～20 mm的超级单体反射率因子质心点较高,回波核前倾,具有悬垂回波、弱回波区、回波墙和三体散射特征,其零速度线后倾,辐合区高度超过- 10℃层,顶部为强辐散区,- 20～0℃层回波最大强度超过55 dBz,50 dBz回波厚度6 km,垂直累积液态水含量(VIL)密度2.2 g·m~(-3)。冰雹直径5～8 mm和未降雹超级单体回波核直立,悬垂回波特征不显著,辐合区高度偏低,辐散区厚度大于辐合区厚度,不同等温层回波强度差别小,但50 dBz回波厚度6 km,VIL密度2.2 g·m~(-3)。 相似文献
6.
云南一次强对流冰雹过程的环流及雷达回波特征分析 总被引：20，自引：5，他引：20
详细分析了云南2001年7月6日强对流冰雹天气过程的多普勒雷达加密观测回波资料和各种物理量场。结果表明,高层辐散流场和低层辐合流场的配置形成大气强烈不稳定,在有利的大尺度背景条件下产生的三个中-β系统直接导致此次滇中强对流冰雹天气过程,在多普勒雷达回波上具有典型的右后侧V型槽口回波、弱回波区(WER)、弓形回波、阵风锋回波、钩状回波、回波墙穹隆(弱回波区)和悬挂回波等特征,并且强回波区与多普勒雷达速度场上的逆风区、大风区和风辐合区相关。 相似文献
7.
《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
8.
江西两种典型强对流天气的雷达回波特征分析 总被引：2，自引：9，他引：2
选取江西12次典型强对流天气过程,从7个方面对冰雹、雷雨大风和短时强降水2种强对流天气的多普勒天气雷达回波特征进行对比分析。分析结果表明,江西冰雹、雷雨大风天气45～55 dBz强回波平均高度为12.6 km,≥-25℃等温层的高度,比短时强降水天气高5.7 km。弱回波区或有界弱回波区、三体散射长钉、持续高垂直积分液态水含量、中气旋、下湿上干和强风垂直切变等,都是冰雹、雷雨大风天气的典型特征;相对平均径向速度图上“S”形暖平流及表现强低空急流的“牛眼”、深厚的湿度层等,则是短时强降水天气的主要特征。 相似文献
9.
摘 要：利用常规观测、北京和天津多普勒天气雷达探测等资料，对2020年6月25日夜间发生在河北省廊坊市一次冰雹、雷暴大风和短时强降水等强对流天气过程进行分析。结果表明：此次超级单体风暴发生的背景条件为高空冷涡前部高空槽叠加地面冷锋系统，高CAPE值、强垂直风切变以及适当的0 ℃和-20 ℃高度等为其发展维持提供了有利的环境条件。超级单体属于右移强风暴，发展演变过程中回波形状不断变化，中气旋特征持续存在，回波垂直结构呈现出回波墙-回波悬垂和有界弱回波区-三体散射和旁瓣回波等典型超级单体雷达回波特征。在本次过程中，55 dBz及以上强回波迅速向高层伸展后迅速下降并配合较低的强回波质心高度，预示地面将出现大冰雹和灾害性大风；VIL最大值达到55 kg?m-2可以作为本地发布冰雹预警的指标，发布冰雹预警时间可以提前12 min；将VIL值升到40 kg?m-2作为地面灾害大风预警指标，发布雷暴大风预警的提前量为24 min。三维空间图像可以直观地展现出超级单体的空间结构。 相似文献
10.
分析延安市2006年8月1日至2日出现的一次大冰雹过程的多普勒雷达产品,得出大冰雹形成过程中形成的三体散射长钉和相应的反射率因子、径向速度、组合反射率、垂直累积液态含水量、回波顶高等变化特征,三体散射现象是大冰雹预警的一个指标。指出强风暴顶辐散是与风暴中强上升气流密切相关的小尺度特征,它提供了上升气流强度的度量,可以与最大冰雹尺寸相关连,并且是风暴强度变化的早期指标。回波强度最大值及所在高度,有界弱回波区区域大小,垂直累积液态含水量的大值区都是判别强降雹潜势的指标。通过对各项产品数据特征变化研究。为今后大冰雹早期预报提供参考。 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