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1.
利用常规天气图,河南省自动站观测资料,濮阳新一代多普勒雷达回波资料,对2014年6月19日14—16时发生在濮阳市北部的一次雷雨大风强对流天气过程进行了综合分析。结果表明:(1)此次雷雨大风过程是由500hPa河套地区低槽、700hPa河套低涡及其携带的人字形切变线、850hPa切变线、地面中尺度辐合线及华北冷空气南扩共同影响造成的。(2)上干冷下暖湿、中低层又有干冷空气的侵入、高空有较强偏西风气流存在的大气层结,为此次强对流天气的发生提供了有利的环境条件。(3)大风发生时雷达回波最强,基本反射率因子图上中心强度达到48dBz,回波顶高图上最大高度达到13km以上,径相速度图上表现为γ中尺度气旋式涡旋。 相似文献
2.
《贵州气象》2019,(6)
该文利用2005-2014年丰都县地面天气、探空数据、NCEP 1°×1°FNL再分析资料等,对丰都地区冰雹、雷暴大风、短时强降水这3类强对流天气特征进行统计分析,得出这3类强对流天气的时空分布特征,并从天气个例出发,利用实况资料对强对流天气的差异进行分析,为强对流天气的预警预报提供参考。得到如下结果:短时强降水通常出现在5-9月,大风通常出现在5—8月,冰雹通常出现南部的七跃山脉和北部的蒋家山和黄草山脉附近~([1]),2005—2014年间共出现了7次,3—8月均有发生。通过计算3种强对流天气环境场参量,归纳出3种物理量参数的差异:大气可降水量、AT500-T850,K指数、抬升指数(LI)、相对湿度、散度场分布等在冰雹、短时强降水和大风天气中有明显的差异,冰雹和短时强降水的AT500-T850相差了近5℃,大风天气的值介于冰雹和短时强降水之间。大气可降水量分布上,短时强降水的大气可降水量(PW)平均值为58 mm,比冰雹值大约多了10 mm,比大风值多了14 mm。短时强降水出现时几乎整层都是处于饱和的状态,冰雹和大风天气几乎只在中低层有较饱和的水汽,而高层的相对湿度平均值在40%～50%左右。对流指数方面,K指数和LI指数都很好的指示了强对流天气的发生,K指数在短时强降水发生时其平均值在39.8℃左右,较冰雹和大风分别高1.6℃和3℃。短时强降水出现环流位置大多位于600 hPa以下,而冰雹则在300 hPa左右,大风在400 hPa左右。 相似文献
3.
一次冷涡横槽型强对流天气过程分析 总被引：2，自引：0，他引：2
利用加密探测资料和新一代天气雷达产品资料,对2012年7月12日夜到13日凌晨发生在河南省东北部的一次局地强对流天气过程进行分析可知:此次过程为典型的东北低涡后部横槽转竖携带冷空气下摆造成,发生在弱垂直风切变和大CAPE的环境条件下,具有干对流特征,850-500 hPa的温差在25～30℃之间,高空冷槽叠加低层暖脊,使得CAPE从当日08时的≤1000 J/kg增大到20时的1000～3500 J/kg;郑州0-6 km和0-2 km的垂直风切变分别是6.06 m/s和2.89 m/s,属弱垂直风切变.地面中分析表明,强对流天气发生在地面高温高湿及等温、等露点线密集区和辐合相叠加区.雷达资料分析表明:此次强对流回波自山东南部生成并向西传播影响开封地区,随后与西北和北部东南移的对流回波在新乡地区东部汇合加强,然后西移影响郑州地区;径向速度图上具有明显的辐散系统和大风区,在大风发生时段有中气旋产品出现,中气旋直径为4.50～5.00 km,大风发生前后中气旋的切变值由10×10-3s-1增大到16×10-3 s-1,最大值52×10-3 s-1出现在00:37,即延津大风发生时和兰考大风发生前19～ 44 min,为强对流天气的临近预报预警提供了参考依据.SWAN产品虽有偏差,但具有一定参考价值. 相似文献
4.
利用2016—2021年ECWMF集合预报资料、浙江自动站实况资料等,计算浙江短时强降水、雷暴大风和冰雹等强对流天气相关物理量的极端天气预报指数（EFI：Extreme Forecast Index）,分析EFI分布特征,并构建了分类强对流预报模型。结果表明：强对流天气与物理量的EFI有密切联系,发生短时强降水时,对流有效位能、整层可降水量、850 hPa与500 hPa温差和位温差的EFI较大,而垂直风切变的EFI为负值,因而较小的垂直风切变更有利于出现极端降水;发生雷暴大风和冰雹时,对流有效位能、850 hPa与500 hPa温差和位温差以及850 hPa温度露点差的EFI较大,700 hPa露点温度的EFI为负值,与上层干冷下层暖湿的有利层结条件有关。利用支持向量机多分类方法,将强对流天气相关物理量的EFI作为特征值开展训练,构建的预报模型对于非局地强对流天气有较好的预报效果,其中短时强降水的误判率明显低于雷暴大风。 相似文献
5.
对强对流天气12 h以上的潜势预报尤其是分类预报,目前仍是天气预报业务中的难点。2018年3月4日江西遭遇一次极端雷暴大风天气过程(简称"3·4"江西雷暴大风过程),虽然江西省气象台3月2日对外发布了区域性雷暴大风、冰雹等强对流天气预报,但对其极端性和开始影响江西的时间等事先估计不足。利用主流数值预报模式产品,对照强对流概念模型条件,对"3·4"江西雷暴大风过程的实时预报思路、经验和不足进行了总结分析与反思。结果表明:(1)该过程天气形势符合我国槽前暖平流强迫类强对流概念模型,其有利的环境条件为500 h Pa有大经向度高空低槽东移,且槽前有干冷舌;低层有异常强盛的西南急流及脉动,其脉动加强特征与我国南方西南急流通常在早上加强的日变化特征完全不同;同时低层湿舌明显增强,与500 hPa形势对应,形成上干冷、下暖湿环境条件。(2)地面低压倒槽异常发展,超低空急流上有风向或风速辐合时,导致地面暖区辐合线生成,是判断强对流午后先在强西南气流的暖区中形成的重要判据之一。(3) 3月4日江南地区850 hPa与500 hPa温差(T850-500)、对流有效位能(CAPE)等多个不稳定指数异常偏强,均明显高出其气候平均态。(4)深刻理解强对流概念模型、准确把握气象要素和物理量平均值态与异常、细致分析有别于其日变化的急流变化特征,是做好此类罕见致灾性雷暴大风潜势预报的关键着眼点。 相似文献
6.
利用常规地面、高空气象资料,郑州站探空订正资料,濮阳气象站实况资料,濮阳和郑州新一代多普勒雷达资料等,对2017年4月13日下午发生在濮阳市的雷暴大风、冰雹等强对流天气过程进行了综合分析。结果表明:(1)本次强对流天气是在中低层低槽东移,地面辐合线南压等大尺度系统影响下产生的;冰雹发生在低空西南暖湿气流大风速带左侧边缘、高空80m/s偏西风急流核出口区左侧、地面辐合线附近。(2)强对流发生前,华北地区850hPa为暖温度脊,500hPa为冷温度槽,形成有利于强对流天气发生的不稳定层结;850、700hPa干湿区错位叠加及露点锋的存在,说明低层在水平和垂直方向上干湿分布极不均匀。(3)郑州站探空订正资料显示,中等以上强度的垂直风切变,有利于强对流风暴的组织发展,深层的垂直风切变构成了冰雹产生的有利环境条件。(4)多普勒雷达组合反射率因子图上对流单体中心强度达65dBz,有超级单体生成;剖面图上有弱回波区、回波悬垂出现;速度图上有低空和超低空急流、27m/s的风速大值区及低层径向辐合、弱中气旋等;垂直积分液态含水量达63kg/m^2,最大回波顶高13km以上。 相似文献
7.
基于地面观测和探空资料、NCEP／NCAR 1°×1°再分析资料，利用中尺度分析技术，对2008—2018年暖季（4—10月）发生在浙江中西部地区（简称浙中西）的65次强对流天气过程进行天气形势配置，得到发生在浙中西的雷暴大风、冰雹、短时强降水及混合性强对流的规律特征。结果如下：（1）浙中西强对流天气出现的大尺度环流有5种基本流型配置：干冷气流型（6.2%）、锋生切变型（13.8%）、暖湿气流型（38.5%）、副高边缘型（30.7%）、台风外围型（10.8%），并给出了每种概念模型下的主要物理机制和中尺度特征。（2）分析了不同概念模型下典型强对流天气个例，简要归纳出各种流型下的主要系统配置和演变规律，并将抽象的概念模型应用到实际预报分析中。（3）分析不同流型下强对流的阈值范围，如干冷气流型Iw大风指数平均为26.1 m·s-1，850 hPa与500 hPa温差可达27.5℃，500 hPa相对湿度平均只有15％等，提炼出相似环流形势下不同强天气的主要预报指标，为强对流预报提供量化参考。 相似文献
8.
利用常规观测资料以及气象卫星云图、雷达监测产品、NCEP/NCAR1°×1°再分析资料,对2008年6月3日发生在鄂东黄冈市的强对流天气过程进行天气学和动力学诊断分析。结果表明:这次强对流天气过程主要是华北冷涡后部偏北气流带来的强冷平流和中低层暖湿切变线所致,下层暖湿、上层干冷的对流不稳定层结为强对流的形成和发展提供了十分有利的条件;强对流天气发生在对流云团移动前方TBB等值线密集区与TBB冷中心之间的区域;典型弓形回波引起的地面大风对应的近地层径向速度图上一般表现为很强的辐散流场;当风暴相对螺旋度(SRH)大于150m2·s-2时,冰雹、大风和短时强降水等出现的可能性非常大,且SRH值越大,风暴旋转性越大,造成地面大风越强。 相似文献
9.
东北冷涡对江淮飑线生成的影响研究 总被引：7，自引：0，他引：7
利用常规气象资料、自动站资料、卫星和雷达资料以及NCEP再分析资料,对近10年东北冷涡天气背景下强对流天气过程的物理机制和中尺度特征进行了分析,并重点分析了在东北冷涡背景下,2009年6月3、5和14日在黄淮和江淮地区分别产生飑线并造成大范围雷雨大风、冰雹等强对流天气。结果表明,在东北冷涡发展阶段,即温压结构不对称、大气斜压性强时,冷涡的西、西南、南至东南部容易发生雷雨大风、冰雹等强对流天气。在东北冷涡形势下,飑线生成时具备以下特征:(1)存在明显的中尺度气旋式环流,850 hPa、925 hPa和地面有辐合线或干线存在;(2)静力不稳定,中低层温度直减率大;(3)风垂直切变强,风随高度强烈顺转,400~500 hPa有西风急流存在,且与强对流天气的发生区域紧密相关;(4)伴随着飑线发展,在飑线后侧有显著升压,雷暴高压的强弱不仅指示了飑线发展的不同阶段,同时可作为地面大风预报的参考依据;(5)飑线的移动与对流回波的传播、出流边界和引导气流密切相关。 相似文献
10.
利用常规气象观测资料和NCEP(1°×1°)再分析资料对2018年4月14日下午—15日凌晨左右发生在桂西南的一次强对流天气过程进行分析,结果表明:此次强对流天气过程具有持续时间长、影响范围广、小时雨强较大、前期以降雹为主、后期以短历时强降水为主的特点;近地层锋面和辐合线是此次强对流天气发生的重要触发机制;200 hPa高空辐散流场有利于底层辐合上升运动的加强,可以弥补500 hPa弱槽槽前动力抬升机制的不足;对流层中层具有干冷空气的侵入是预报强对流天气的关键因子,而地面强对流天气容易发生在干空气侵入700 hPa层之后数小时内;强对流天气容易发生在θse大值区或者舌区;对流层正涡度从中层下传到底层对于预报强对流天气的出现具有一定的指示意义;雷达产品分析表明回波具有明显的悬垂回波、弱回波区、辐合区、中气旋、三体散射长钉和旁瓣回波特征。 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.
Fei LIU Chen XING Jinbao LI Bin WANG Jing CHAI Chaochao GAO Gang HUANG Jian LIU Deliang CHEN 《大气科学进展》2020,37(7):663-670
正The Taal Volcano in Luzon is one of the most active and dangerous volcanoes of the Philippines. A recent eruption occurred on 12 January 2020(Fig. 1a), and this volcano is still active with the occurrence of volcanic earthquakes. The eruption has become a deep concern worldwide, not only for its damage on local society, but also for potential hazardous consequences on the Earth's climate and environment. 相似文献
13.
The moving-window correlation analysis was applied to investigate the relationship between autumn Indian Ocean Dipole (IOD) events and the synchronous autumn precipitation in Huaxi region, based on the daily precipitation, sea surface temperature (SST) and atmospheric circulation data from 1960 to 2012. The correlation curves of IOD and the early modulation of Huaxi region’s autumn precipitation indicated a mutational site appeared in the 1970s. During 1960 to 1979, when the IOD was in positive phase in autumn, the circulations changed from a “W” shape to an ”M” shape at 500 hPa in Asia middle-high latitude region. Cold flux got into the Sichuan province with Northwest flow, the positive anomaly of the water vapor flux transported from Western Pacific to Huaxi region strengthened, caused precipitation increase in east Huaxi region. During 1980 to 1999, when the IOD in autumn was positive phase, the atmospheric circulation presented a “W” shape at 500 hPa, the positive anomaly of the water vapor flux transported from Bay of Bengal to Huaxi region strengthened, caused precipitation ascend in west Huaxi region. In summary, the Indian Ocean changed from cold phase to warm phase since the 1970s, caused the instability of the inter-annual relationship between the IOD and the autumn rainfall in Huaxi 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.
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
16.
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
17.
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
18.
基于最新的GTAP8 (Global Trade Analysis Project）数据库,使用投入产出法,分析了2004年到2007年全球贸易变化下南北集团贸易隐含碳变化及对全球碳排放的影响。结果显示,随着发展中国家进出口规模扩张,全球贸易隐含碳流向的重心逐渐向发展中国家转移。2004年到2007年,发达国家高端设备制造业和服务业出口以及发展中国家资源、能源密集型行业及中低端制造业出口的趋势加强,该过程的生产转移导致全球碳排放增长4.15亿t,占研究时段全球贸易隐含碳增量的63%。未来发展中国家的出口隐含碳比重还将进一步提高。贸易变化带来的南北集团隐含碳流动变化对全球应对气候变化行动的影响日益突出,发达国家对此负有重要责任。 相似文献
19.
Using the International Comprehensive Ocean-Atmosphere Data Set(ICOADS) and ERA-Interim data, spatial distributions of air-sea temperature difference(ASTD) in the South China Sea(SCS) for the past 35 years are compared,and variations of spatial and temporal distributions of ASTD in this region are addressed using empirical orthogonal function decomposition and wavelet analysis methods. The results indicate that both ICOADS and ERA-Interim data can reflect actual distribution characteristics of ASTD in the SCS, but values of ASTD from the ERA-Interim data are smaller than those of the ICOADS data in the same region. In addition, the ASTD characteristics from the ERA-Interim data are not obvious inshore. A seesaw-type, north-south distribution of ASTD is dominant in the SCS; i.e., a positive peak in the south is associated with a negative peak in the north in November, and a negative peak in the south is accompanied by a positive peak in the north during April and May. Interannual ASTD variations in summer or autumn are decreasing. There is a seesaw-type distribution of ASTD between Beibu Bay and most of the SCS in summer, and the center of large values is in the Nansha Islands area in autumn. The ASTD in the SCS has a strong quasi-3a oscillation period in all seasons, and a quasi-11 a period in winter and spring. The ASTD is positively correlated with the Nio3.4 index in summer and autumn but negatively correlated in spring and winter. 相似文献
20.
Hourly outgoing longwave radiation(OLR) from the geostationary satellite Communication Oceanography Meteorological Satellite(COMS) has been retrieved since June 2010. The COMS OLR retrieval algorithms are based on regression analyses of radiative transfer simulations for spectral functions of COMS infrared channels. This study documents the accuracies of OLRs for future climate applications by making an intercomparison of four OLRs from one single-channel algorithm(OLR12.0using the 12.0 μm channel) and three multiple-channel algorithms(OLR10.8+12.0using the 10.8 and 12.0 μm channels; OLR6.7+10.8using the 6.7 and 10.8 μm channels; and OLR All using the 6.7, 10.8, and 12.0 μm channels). The COMS OLRs from these algorithms were validated with direct measurements of OLR from a broadband radiometer of the Clouds and Earth's Radiant Energy System(CERES) over the full COMS field of view [roughly(50°S–50°N, 70°–170°E)] during April 2011.Validation results show that the root-mean-square errors of COMS OLRs are 5–7 W m-2, which indicates good agreement with CERES OLR over the vast domain. OLR6.7+10.8and OLR All have much smaller errors(～ 6 W m-2) than OLR12.0and OLR10.8+12.0(～ 8 W m-2). Moreover, the small errors of OLR6.7+10.8and OLR All are systematic and can be readily reduced through additional mean bias correction and/or radiance calibration. These results indicate a noteworthy role of the6.7 μm water vapor absorption channel in improving the accuracy of the OLRs. The dependence of the accuracy of COMS OLRs on various surface, atmospheric, and observational conditions is also discussed. 相似文献