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1.
贵州铜仁暴雨和冰雹雷达回波特征对比分析 总被引：1，自引：0，他引：1
利用铜仁新一代多普勒天气雷达对贵州铜仁区域的局地暴雨和冰雹天气过程的雷达监测常用产品进行对比分析,得出了产生暴雨和冰雹天气时其雷达回波特征的差异性:(1)冰雹回波反射率因子及剖面在较高的高度上维持较大强度,且其剖面通常具有穹窿结构,暴雨回波中通常有多个对流回波柱,强回波核位于云体中下部。(2)局地暴雨天气通常为混合型降水回波的"准静止"状态和长时间的"列车效应",冰雹回波其外形结构多呈点状、块状、带状等特征,有时候还会出现钩状、弓形回波等特殊形状;(3)暴雨径向速度和冰雹径向速度都存在逆风区等特征,短时强降水发生在逆风区边缘地带、径向速度辐合最大的区域。冰雹径向速度变化范围较大,有强烈的风向、风速辐合过程,有时还会伴随中尺度气旋。(4)冰雹回波的垂直液态水含量和回波顶高都比暴雨大,在降雹前2-5个体扫范围内冰雹回波的垂直液态水含量值会出现明显的跳变,而暴雨回波其值比较平稳并且维持较低数值。(5)VWP在冰雹过程中从低层到高层存在垂直风切变,其切变越大,出现冰雹的可能性越大,而暴雨的西风气流风速远小于冰雹过程。 相似文献
2.
利用1°×1°NCEP再分析风场资料、多普勒雷达风廓线（VWP）和速度场产品、L波段雷达单测风资料,对发生在2007年7月29日和2010年7月23日的豫西山区两次致洪暴雨进行了分析。结果表明：在2007-07-29过程和2010-07-23过程的第二阶段中,风场垂直分布具有低层强西南风或南风辐合、高层辐散的特征;VWP产品中西南气流稳定深厚,有利于风暴的持久维持;平均径向速度产品上逆风区对暴雨落区和强度的变化有指示意义。卢氏雷达单测风资料可以弥补多普勒雷达对卢氏降水观测中因山体阻挡带来的缺陷,多种风资料在豫西山区致洪暴雨预报中可互为补充。 相似文献
3.
多种风资料在豫西山区致洪暴雨预报中的应用 总被引：2，自引：0，他引：2
利用1°×1°NCEP再分析风场资料、多普勒雷达风廓线（VwP）和速度场产品、L波段雷达单测风资料,对发生在2007年7月29日和2010年7月23目的豫西山区两次致洪暴雨进行了分析。结果表明：在2007-07-29过程和2010-07-23过程的第二阶段中,风场垂直分布具有低层强西南风或南风辐合、高层辐散的特征;VWP产品中西南气流稳定深厚,有利于风暴的持久维持;平均径向速度产品上逆风区对暴雨落区和强度的变化有指示意义。卢氏雷达单测风资料可以弥补多普勒雷达对卢氏降水观测中因山体阻挡带来的缺陷,多种风资料在豫西山区致洪暴雨预报中可互为补充。 相似文献
4.
为研究暴雨过程中逆风区特征及应用判据,统计分析2010—2017年山东临沂地区暴雨过程中的多普勒雷达观测资料,结果表明：暴雨过程中,风暴内的垂直环流是造成逆风区发生发展的直接原因;逆风区表现为β中尺度和γ中尺度,其形态在不同天气类型下有明显差异;逆风区持续阶段降水强度增大,持续时间与过程累积雨量呈正相关;当雷达最低仰角识别到逆风区,其厚度≥4.0 km、强度≥15 m·s-1、径向速度绝对值最大值≥5 m·s-1且持续30 min以上时,风暴常明显发展,相关特征可用于预报风暴和暴雨的发展。 相似文献
5.
承德市两次局地性短时暴雨过程的中尺度特征对比分析 总被引：1，自引：0，他引：1
2014年6月17日和7月15日,同样在冷涡系统影响下,河北省承德市区先后出现了两次局地性短时暴雨天气过程(小时雨强分别为39.6和66.1 mm·h~(-1),最大10 min雨强分别为15和18 mm)。本文利用常规观测资料、5~10 min加密自动站资料、多普勒雷达数据、卫星云图数据以及NCEP再分析资料,对这两次短时暴雨过程的中尺度特征进行对比分析。结果表明:分钟级降水观测显示,"6·17暴雨"过程10 min雨量随时间表现为持续时间分别约为半小时的双峰型分布;"7·15暴雨"过程降水呈单峰型,持续时间不足1 h;两场局地暴雨是在高空冷涡环流背景下产生的,其触发系统均为地面中尺度辐合中心(辐合线),降水峰值与东南风或风速增大相关联,6 m·s~(-1)的东南风有利于强降水的维持。卫星资料显示,"6·17暴雨"过程直接影响系统为β中尺度对流系统,强降水与TBB低值区对应,"7·15暴雨"强降水对流系统则表现为γ中尺度,与TBB大梯度区对应。"6·17暴雨"过程对应水平尺度近20 km,生命史约半小时,回波强度达65 dBz对流单体回波的合并增强。"7·15暴雨"过程则表现为多个水平尺度不足5 km,生命史不到1 h,回波强度达55 dBz的对流单体回波依次经过承德市区,因"列车效应"造成。两次降水过程中逆风区的出现时间都与强降水时段有很好的配合,且逆风区的持续时间越长,产生的降水强度也越大。 相似文献
6.
利用梵净山周边区域自动站逐小时降水资料和铜仁雷达观测资料,对2017—2018年铜仁市梵净山周边区域暴雨过程中逐小时分级降水的雷达类型和回波特征进行分析。结果表明:①梵净山区域暴雨过程中小雨、中雨、大雨年均总站次的日变化均呈双峰型分布,而暴雨年均总站次呈单锋型,并且具有明显的夜雨特征。②造成梵净山区域暴雨天气的雷达回波类型可分为本地发展型、移入型和合并加强型3种。③小时雨强与回波强度呈正相关,而与移动速度呈反相关。④径向速度图上中雨量级降水有弱辐合特征,大雨量级降水出现弱的逆风区结构,暴雨量级降水有明显的辐合辐散和速度对特征,且存在逆风区结构,逆风区位置对应强回波中心。⑤垂直累计液态水含量大值区及回波顶高度与反射率因子大值区有较好的对应。 相似文献
7.
“海棠”影响河南降水雷达回波和中尺度雨团对比分析 总被引：5，自引：1，他引：5
使用郑州714CD雷达观测资料，以及2005年刚建立起的河南省乡镇雨量站网资料，配合河南省自动站资料，对0505号台风海棠造成的河南省大范围暴雨、局部特大暴雨过程进行了分析，总结出强降水回波区早于中尺度雨团1个小时左右生成，中尺度雨团早于降水回波减弱消失，稳定少动的强降水回波有利于中尺度雨团的产生和发展；多普勒速度场上，中尺度系统存在的地方有利于强降水回波发展和维持，也有利于中尺度雨团产生和发展；受持续不断45dBz左右强降水回波影响，构成“列车效应”，可造成暴雨甚至是大暴雨过程；对于大范围降水回波，依据乡镇雨量图上中尺度雨团活动规律，分析速度场上中尺度系统如逆风区、辐合区、大风区（低空急流），可以准确预报暴雨落区，发布暴雨预警信号。 相似文献
8.
山东一次区域性暴雨中尺度特征分析 总被引：6，自引：0，他引：6
利用常规资料、地面自动站资料、FY2C卫星云图TBB和多普勒天气雷达资料,对2009年5月9—10日发生在山东的春季区域性暴雨进行分析和研究。结果表明:①强降水是在低层冷空气和深厚西南暖湿气流交汇的过程中产生的,副高异常偏强,制约850～700hPa切变线和地面辐合线停滞少动,产生较长时间的降水。②地面辐合线的形成和维持激发了边界层的辐合上升运动,为暴雨区提供了充足的水汽,冷空气从边界层楔入,与暖湿气流汇合并抬升暖湿气流辐合上升,使上升运动加强,降水增幅。③中尺度对流系统是造成暴雨的主要中尺度系统,多个单体更迭并移经同一区域,形成"列车效应"而产生区域性暴雨。④雷达径向速度图中逆风区和不同高度(超)低空急流的大小对短时强降水预报有一定的指示意义。 相似文献
9.
利用南京多普勒天气雷达径向速度数据,对2012年春季南京地区首场暴雨过程进行了分析。结果表明,风廓线产品(VWP)在降水各阶段都呈现出相应的图像特征:中上层降水云系向下扩展而同下层降水云系"连接",形成"ND"楔形区域,是降水即将开始的一个信号;降水发展阶段大风区底高变化与雨势有较好的对应关系,大风区底高持续下降并维持某一高度后的30 min内,雨势增强明显,随着大风区底高的快速升高,雨强也迅速减弱。降水末期中层"ND"的出现预示着降水云系逐渐消散,风向杆位置的连续下降预示着降水即将减弱停止。逆风区断裂位置及边缘地带对应着强降水的落区。由雷达基数据计算出的平均散度信息较好地反映了此次降水的动力学特征。 相似文献
10.
利用常规观测资料、加密自动站资料和多普勒天气雷达资料,对滇东北2010年7月接连发生的三次局地暴雨过程进行诊断分析.结果表明:三次暴雨过程均发生在西太平洋副热带高压边缘,其环流背景分别为两高辐合型、低涡切变型和东风波型:天气尺度辐合上升运动和低层不稳定能量释放产生的小尺度上升运动协同是三次局地暴雨发生的原因;三 次暴雨均由SW-NE向短带对流回波单体产生,强回波带西南端降水强度最大;径向速度图上出现逆风区、低空急流、冷暖平流以及低层中尺度辐合线,逆风.区与暴雨落区对应较好,逆风区向上伸展高度与降水强度相对应,逆风区的出现比暴雨出现有1 h的提前期,对暴雨短时预报具有重要指示意义. 相似文献
11.
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
12.
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
13.
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
14.
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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《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
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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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《大气和海洋科学快报》2012,(3):273
正AIMS AND SCOPE Atmospheric and Oceanic Science Letters (AOSL) publishes short research letters on all disciplines of the atmosphere sciences 相似文献