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1.
采用LAPS中尺度分析模式大气资料,对2008年7月一次西南涡暴雨过程进行天气学降水运动的中尺度诊断计算与分析。诊断计算包括：可降水量、层结不稳定能量、对流可降水量、水汽权重平均风速、水汽通量散度、云水、云冰总量及其通量散度和垂直速度与凝结函数降水率等。结果表明：“西南涡-切变线”系统的暴雨发生在暖湿气团与变性冷气团之间的中尺度风场辐合上升运动区,中尺度雨团发生在层结不稳定的暖湿气团一侧。计算的中尺度垂直运动与凝结函数降水率场,降水率为暴雨到特大暴雨。计算的水汽通量辐合降水率与凝结函数降水率不会完全重合,且水汽通量辐合既可致中尺度“雨”,又可成大尺度“云”,并且云水、云冰通量辐合/辐散,可解释为它们的“正”/“负”碰并增长,而碰并增长产生水凝物增量（降水率）也促成大暴雨。因此,在凝结函数降水率场中产生的中、小尺度对流雨团,加上水汽与云水、云冰通量辐合及其碰并增长,并且借助层结不稳定能量释放和可能产生的强迫“次级环流”及水汽与云水、云冰输送,是这次“西南涡-切变线”系统造成襄樊特大暴雨的天气学成因。 相似文献
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按天气学方法,对2010年6月华南—江南持续暴雨作大尺度水汽场诊断分析,同时用三重嵌套WRF中尺度模式,模拟6月19—20日"高空槽-西南涡-切变线-低空急流"系统造成的江南特大暴雨过程,并且对模拟中尺度暴雨雨带和雨团作高时空分辨率诊断分析。诊断物理量包括:可降水量、对流可降水量、水汽及云水、云冰通量和通量散度、水汽权重平均风速、凝结函数降水率等。模拟与诊断分析表明,华南江南持续性暴雨大尺度水汽场特征是,因东亚"中高纬度正距平中低纬度负距平副高偏强偏西季风槽异常活动",造成孟加拉湾和南海上空的大尺度水汽进入大陆;中尺度特大暴雨发生在上游区有暖湿急流、并处于风场辐合的"水汽+云水+云冰"(总水物质)饱和高值区;因凝结函数降水率和总水物质通量散度降水率均为风场(散度场)中垂直运动产物,模拟的凝结函数降水率随模式时空分辨率提高而逐渐逼近于模式的显式降水物理过程,当模式分辨率达到4 km,可模拟出"西南涡切变线"系统中,有凝结函数降水率为1~3 mm·min~(-1)的中尺度雨团生消;且模式大气中的云水、云冰碰并增长降水率,可用其通量散度描述,并且应与凝结函数降水率相叠加。从而表明,模拟中尺度雨带和雨团发生、发展的天气学动力因素,只能是天气系统风场,即是模式的高时空分辨率散度场决定模式大气垂直运动,进而决定凝结函数降水率和总水物质通量散度降水率,它们一起构成了模式显式降水(率)。 相似文献
3.
利用常规和地面加密气象观测资料、卫星云图、NCEP再分析资料及中尺度模式MM5,对2006年7月23日一次阻塞型华北暴雨过程进行了诊断分析和数值模拟。结果表明,此次暴雨过程发生在以东西伯利亚阻塞高压为典型特征的大尺度鞍型场的背景下,宽广的低压区及高、低空急流次级环流为中尺度对流系统(MCS)的发生、发展提供了适宜的环境和动力强迫;700hPa和850hPa天气尺度的偏西水汽输送和低涡北侧的偏东水汽输送改善了环北京地区的水汽条件,暴雨发生前850hPa中尺度西南水汽输送对北京暴雨的发生有直接影响;MM5模式再现了导致MCS的形成及演变过程;中-β尺度MCS是这次暴雨的直接触发系统,其水平尺度约为0.5个经距,垂直方向由地面伸展到300hPa左右,具有典型的暖心结构,辐合、辐散中心分别位于900hPa和400hPa;MCS北侧强垂直次级环流为强对流的产生创造了有利条件。同时,MCS南侧相当位温的强梯度高能区及该区域的不稳定能量输送也是暴雨发生的重要条件。 相似文献
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利用MICAPS系统资料对2005年8月12日发生在山西朔州市北部的暴雨天气过程的大尺度环流背景和物理量场进行分析。结果表明:这次暴雨天气过程发生在纬向环流向经向环流调整的过程中,西太平洋副热带高压有一次明显的西伸北抬,是一次典型的副高西北侧西南气流型暴雨。降水水汽主要来自南海,中低层的水汽输送十分充沛,并在朔州市北部形成辐合。低空急流的建立,为此次强降水提供了丰富的水汽和位势不稳定能量;过程期间,物理量场表现出强水汽输送辐合及上升运动;冷空气与暖湿气流及特殊地形的综合作用激发出中尺度降水云团,造成此次强降水。 相似文献
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从一次大暴雨过程看大中尺度间的相互作用 总被引：2，自引：0，他引：2
应用大尺度物理量场诊断分析和中尺度带通滤波处理技术,对1994年6月29日发生在山东的一次大暴雨过程机制进行了分析。结果表明,大尺度θse锋区、水汽强烈输送、大气潜在不稳定等是大暴雨发生的有利环境条件;而经带通滤波得到的中尺度涡旋、切变线则是直接造成山东此次大暴雨发生的影响系统;中尺度涡旋、切变线与大尺度物理量场关系密切。 相似文献
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用NCEP/NCAR全球逐日再分析格点资料和广西区域日降水资料,对2008年6月12—13日发生在广西的持续性暴雨过程进行了诊断分析,并利用中尺度数值模式WRF进行了数值模拟研究。结果表明:暴雨过程的水汽来源主要为孟加拉湾南部和南海北部;在强降水期间,暴雨区上空低层为较强的大气层结不稳定区,中高层为大气层结相对稳定区,不稳定能量与降水强度有着很好的对应关系;西南急流作为对流系统上升的触发机制,为广西持续性暴雨过程的发生和发展提供了水汽条件和动力条件。WRF模式成功模拟出本次暴雨过程的大尺度环流形势的演变及中尺度降雨分布,本次暴雨与850hPa上一个β中尺度低涡的生成和强烈发展直接关联。 相似文献
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利用2007年5月30～31日天气图、物理量场、卫星云图和雷达回波资料及常规观测资料,采取天气学诊断分析方法,对湖北省初夏一次暴雨天气过程的大尺度环流特征、中尺度系统和强降水成因进行了分析。结果表明:高层辐散、冷空气与西南暖湿气流交绥、鄂中切变线维持、副热带高压稳定少动,是这次暴雨发生发展的有利大尺度环流背景;强对流云团或西南低涡中尺度云团是造成江汉平原北部、鄂东及鄂西南北部强降水的主要云团;整个暴雨过程伴随着强对流雷达回波的初生、发展、合并和减弱,降水主要由逐渐发展的强回波造成;低空急流输送水汽、中低层层结对流不稳定、低层辐合与高层辐散配置以及暴雨区存在较强锋生作用是此次暴雨的主要降水成因。 相似文献
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利用逐小时降水、雷达、FY-4A卫星等观测资料及ERA5逐时再分析资料,分析了2021年4月23日秦巴山脉大范围区域性暴雨过程的中尺度特征、水汽和环流异常特征,结果表明,该次暴雨过程范围大,多站降水量突破历史同期极值,且大巴山区出现了山地突发性暴雨事件。500 hPa秦巴山脉异常的“东高西低”环流形势维持使得青藏高原至陕西间的气压梯度力增大,中层西风气流增强。中低层多尺度天气系统的叠加作用是造成该次暴雨的背景动力条件,西南低涡前方的东南气流一方面与北侧偏东风形成的切变线为暴雨发生提供了环境场的辐合上升运动,另一方面将西南气流和偏南气流带来的水汽输送到秦巴山脉汇聚。同期近海台风和东北冷涡活动相关联的环流导致东北路径的水汽输送异常强(贡献达到30%),成为本次暴雨过程水汽来源的独特之处。与历史同期比,偏南通道和东北通道的水汽路径上比湿都是异常的正距平,说明暴雨期水汽来源丰沛。暴雨过程主要由西南低涡前方的一个中尺度对流系统活动造成,大巴山区迎风坡对气流的地形抬升与环境场偏南气流的辐合上升叠加,对流活动强,降水强度大且突发性强;而秦岭山区近地面是偏东风在山前辐合抬升,中层为西南引导气流的环境场... 相似文献
10.
2011年山东雨季首场暴雨过程诊断分析 总被引：2，自引：0，他引：2
利用NCEP1°×1°再分析资料、卫星及常规观测资料,对2011年山东进入雨季后的首场暴雨天气过程的大尺度环流背景、物理量场的结构特征及暴雨的中小尺度系统进行了分析。结果表明：此次暴雨是高空低槽、低空切变线和地面中尺度辐合线共同影响造成的,西南低空急流为暴雨区提供了充沛的水汽和能量;水汽通量散度所揭示出的强水汽辐合中心与强降水中心具有很好的对应关系;暴雨落区与强上升运动中心在时间和空间上相关性较好;此次降水是位于低空切变线右侧,低空急流左侧的暖区里的暴雨。 相似文献
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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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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
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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
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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
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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