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1.
《贵州气象》2021,(3)
利用常规高空和地面探测、观测资料,地面加密自动站分钟数据资料以及榕江站、贵阳站C波段多普勒天气雷达探测资料,分析了2020年3月23日贵州强对流天气的环流形势,并重点分析了榕江飑线大风及长顺大冰雹雷达回波特征。结果表明:(1)此次飑线大风与大冰雹发生在南支槽前暖区,地面热低压发展推动辐合线移动、低层西南暖湿气流、中层干冷空气、合适的0℃和-20℃高度均为此次飑线大风及大冰雹的产生提供了有利的环境条件。(2)雷达回波大冰雹特征突出:强回波悬垂,有界弱回波区,弓形回波,中心强度强(60 dBz以上)且50 dBz强回波伸展超过-20℃高度达到9 km以上,垂直积分液态水含量最高达到了70 kg/m~2,连续超过两个体扫VIL≥60 kg/m~2,回波顶高连续超过两个体扫在15 km以上。(3)飑线雷达回波大风特征明显:弓形回波形态特征明显且移动较快,移速约40 km/h,低层径向速度大,中层径向辐合大风区下传,速度零线通过观测站后大风加速。(4)短临预警业务中,对飑线大风天气,应重点关注低仰角速度大值区、中层径向辐合和弓形带状回波生成后移动发展对下游地区的影响;对大冰雹天气,应重点关注大于50 dBz强回波垂直扩展的高度、VIL和ET高值区的维持等。 相似文献
2.
利用日常业务常规高空和地面探测、观测资料,地面加密自动站分钟数据资料以及榕江站、贵阳站C波段多普勒天气雷达探测资料,分析了2020年3月23日贵州榕江飑线大风及长顺大冰雹的成因及雷达回波特征 。结果表明：（1）此次飑线大风与大冰雹发生在南支槽前暖区,地面热低压发展推动辐合线移动、低层西南暖湿气流、中层干冷空气、合适的0℃和-20℃高度均为此次飑线大风及大冰雹的产生提供了有利的环境条件。（2）雷达回波大冰雹特征突出：强回波悬垂,有界弱回波区,弓形回波,中心强度强（60dBz以上）且50dBz强回波伸展超过-20℃高度达到9km以上,垂直积分液态水含量最高达到了70kg/m2,连续超过两个体扫VIL≥60kg/m2,回波顶高连续超过两个体扫在15km以上。（3）飑线雷达回波大风特征明显：弓形回波形态特征明显且移动较快,移速约40千米/小时,低层径向速度大,中层径向辐合大风区下传,速度零线通过观测站后大风加速。（4）短临预警业务中,对飑线大风天气,应重点关注低仰角速度大值区、中层径向辐合和弓形带状回波生成后移动发展对下游地区的影响;对大冰雹天气,应重点关注大于50dBZ强回波垂直扩展的高度、VIL和ET高值区的维持等。 相似文献
3.
新疆一次强飑线过程双多普勒雷达观测的中尺度风场结构分析 总被引：8，自引：4，他引：4
利用新疆乌鲁木齐和五家渠的双多普勒雷达同步观测资料与双多普勒雷达风场反演技术,结合多种气象资料(1 min间隔的地面自动站资料、探空资料和NCEP再分析场资料等),综合分析了2005年6月26日新疆乌鲁木齐附近一次强飑线过程。其流场特征是低层存在明显的辐合线,中层辐合,高层辐散。中低层的风场辐合使旧回波右侧(西南侧)一定距离处依次生成新回波并与旧回波合并,对流单体间的辐合线促使其迅速合并,是飑线发展的重要原因。对流单体间的合并是从中层开始的,然后扩展到低层。在低层对流单体合并后,飑线前部有一明显的辐合线,入流区、大的回波强度梯度区和弱回波区非常明显;同时,不同发展阶段的风场配置有明显的不同,上升气流和下沉气流在多单体风暴中同时存在。本次飑线过程中低层是东南风的入流气流,与对流带后部的西北风气流相遇后向上倾斜上升,在中高层形成飑前砧状云,这与国内外中纬度飑线的结构基本一致,但本次飑线过程只有前缘强烈的对流区,没有尾随的层状云降水。自动气象站、多普勒雷达及其反演的风场很好地揭示了该飑线的发生、发展、爆发过程及其回波和风场的空间结构特点。 相似文献
4.
利用常规、非常规观测及NCEP再分析资料,对比分析广西壮族自治区桂林市中γ系统造成的极端大风和中β 系统造成的致灾冰雹过程。(1)高低空急流耦合为强对流天气提供有利背景条件,锋面及辐合线为触发系统。大风过程锋面、冰雹过程高空槽动力作用更强。(2) 均具有强的上干冷下暖湿不稳定层结、强下沉动能、CAPE及中低层垂直风切变,大风过程中层干层更显著,冰雹过程CAPE更大。(3) 冷池出流与环境风垂直切变维持平衡使上升速度区呈垂直状态,利于飑线发展。变压风与冷池共同影响使风暴发展并向变压低中心移动,大风过程冷池前沿与变压低中心在广西临桂迭加,表明强风暴造成的下击暴流与低层中气旋迭加导致极端大风。(4) 大风、冰雹均由镶嵌在飑线系统中的超级单体风暴造成,超级单体强回波中心达65 dBZ,具有弱回波区、三体散射。大风过程强风暴借助冷锋热力边界的斜压性形成低层中气旋,低层钩状回波更明显,并有明显的MARC及强回波核心下降特征;冰雹过程强回波质心高,VIL达55~65 kg/m2,并有跃升现象。(5) 均有中等强度中气旋。大风过程中气旋比冰雹过程低,半径明显减小。大风过程中气旋与龙卷涡旋特征同时出现,对极端大风有预警作用。 相似文献
5.
利用常规观测、地面自动站加密观测资料、NCEP(0.25°×0.25°)再分析资料以及多普勒雷达资料等,对2016年9月24日发生在内蒙古东南部一次致灾飑线天气过程进行分析。结果表明:(1)中高层干冷空气扩散东南下与低层西南急流的辐合急剧加强为强飑线提供了非常有利的大尺度环流背景;(2)对流有效位能(CAPE)在强对流爆发前有明显跃升;假相当位温(θse)中低层分布呈显著的倒漏斗状,而且随高度增高递减率明显增大,这种上干下湿的层结有利于雷暴大风和冰雹等强对流天气产生;(3)地面中尺度露点锋(干线)和中尺度辐合线长时间维持、耦合并加强成为这次强对流天气的直接触发和维持机制;飑线后部一直维持雷暴高压,表明有地面大风存在;(4)雷达回波伴有弓形回波特征,低层呈现有界弱回波区(BWER),中高层有明显的回波悬垂,50～55 dBz强回波区延伸到7.5 km,表明对流风暴内有强烈的上升气流,有利于短时强降水和大冰雹的形成;(5)弓形回波径向速度剖面图上存在中层径向辐合(MARC)。 相似文献
6.
2015年5月6日夜间,河南省西北部出现了冰雹、飑线和大风灾害性天气。利用常规观测资料、NCEP(1°×1°)再分析资料及郑州多普勒雷达回波资料,对这次弱降水环流背景下的飑线冰雹过程进行数值分析。结果发现:常规天气尺度环流形势不利于对这次飑线冰雹过程的预判,借助中尺度分析与落区围区法能较好地预报这次冰雹飑线过程;豫西北上空CAPE能量场较弱,水汽条件和不稳定能量也不利于强降水的产生,但由于冷平流入侵和高温高湿不稳定能量在豫西北上空不断堆积,以及冷锋入侵和垂直风切变较大,致使豫西北地区存在对流触发机制;低层辐合、高层辐散的垂直层结结构和垂直上升运动的不断加深,使强对流加强并维持,导致形成冰雹和飑线;-20℃层和0℃层高度适宜,有利于豫西北降雹;V型缺口、雷达反射率因子特征及阵风锋和飑线南北两端的速度场分布,对冰雹和大风预报有较好的指示意义。 相似文献
7.
广西一次飑线大风天气的成因和预警分析 总被引：1，自引：3，他引：1
本文利用常规探测资料、多普勒天气雷达资料、自动站观测资料等对2013年3月27-28日发生在广西的一次飑线大风天气过程进行跟踪及监测预警,对其大尺度环流背景、雷达回波特征以及灾害性大风形成原因进行了较为详细的分析与研究。结果表明:此次飑线过程是由高空冷槽与地面高压后部形势所引起的;假相当位温、T-logp图等分析表明广西上空具有较好的热力、动力条件;地面辐合线触发初始对流活动;发展成熟的飑线地面气压场上存在雷暴高压、飑前低压和飑后低压等中尺度特征;飑线大风等灾害性天气出现在地面高压前侧气压梯度大值区和飑线的断裂处;雷达图像上中层径向辐合、反射率因子核心和中层风速大值区逐渐降低以及垂直风廓线图中低层风的转变等特征信息对地面大风天气临近预警有较好的指示意义;降水粒子的拖曳作用和飑线的快速移动都对地面大风的产生及增幅有一定的作用。 相似文献
8.
2013年7月31日20时-8月1日08时,三门峡地区出现了一次飑线天气过程。对本次过程高低空天气形势、卫星资料、NCEP再分析物理量、雷达产品等资料的分析结果表明:这次飑线天气过程是在上干冷下暖湿的不稳定大气层结条件下产生的,地面辐合线是这次飑线产生的触发机制;飑线发生前热力不稳定层结的存在和中低层的正涡度区、高层的辐散区,对预报强对流天气有一定指示作用;飑线天气发生在Tbb梯度最大区。从雷达回波看,这次飑线过程分为生成、旺盛和消散三个阶段。东西方向飑线由对流单体合并而成,在移动过程中,受中条山地形抬升和黄河湿热河面影响得到发展和增强;南北方向飑线由上游陕西东移过来,受低层强的偏西急流影响形成弓形回波;两个飑线合并成"人字形"共同影响三门峡地区。在飑线旺盛阶段,雷达回波存在低层有界弱回波区和中高层悬垂回波结构,冰雹发生在南北向飑线(弓形回波)后侧;两条飑线回波合并处出现明显的中气旋特征,是产生局地强降水的有利条件。 相似文献
9.
利用常规地面高空观测资料、地面自动站资料、NCEP 1°×1°再分析资料、卫星云图、多普勒天气雷达资料等,对2017年秋季发生在河北省中部的一次由飑线引发的雷暴大风天气进行分析。结果表明：本次雷暴大风过程发生在高空冷涡底部,槽后冷空气与低层暖平流叠加配合地面冷锋的有利天气背景下,由飑线回波直接造成。环境条件中水汽和热力达到了中国华北地区产生强雷暴大风的平均值,大气温度直减率和垂直风切变比夏季更适宜,但能量不如夏季充足。飑线的强度、形态与夏季产生雷暴大风的雷达回波特征无异,但依据低层径向速度大值区预警秋季飑线大风需提高阈值。秋季飑线过程中地面同样伴随风场辐合、雷暴高压等中尺度系统,冷池密度流作用有利于地面大风产生。 相似文献
10.
河北唐山一次飑线过程的中尺度天气分析 总被引：1，自引：0，他引：1
利用常规观测资料、自动气象站资料及雷达资料,对2013年8月4日影响唐山的一次飑线过程进行了中尺度分析。结果表明:500 hPa高空槽是产生这次飑线的主要影响系统,地面中尺度辐合线是这次过程的触发机制;对流层中层干冷空气入侵与低层暖湿气流的辐合增强了大气层结的不稳定;低层辐合、高层辐散进一步加强了垂直运动的发展;中低层垂直风切变则有利于飑线的发展、加强和维持。雷达回波图上可识别出中低空的中尺度辐合线、弓形回波、逆风区等中小尺度结构特征,对于此类强对流性天气的预报具有实际指示意义。 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
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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
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
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<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
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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
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