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1.
典型带状云系强降雨过程卫星云图演变特征分析 总被引：1，自引：0，他引：1
通过对两个典型的带状云系的强降水过程的卫星云图进行定量分析，初步验证了可以用云带0℃边界反映冷高压和副高的活动态势，揭示了降雨强度与云带强度指数及TBB面积指数有很好的对应关系。同时，还研究了暴雨落区与对流云团活动范围的关系，强降水时段与对流云团的发展阶段的对应关系。 相似文献
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短时区域性暴雨的形成一般有两种情况:大多数是发展强盛的对流云团、云带产生的强降水,短时间内雨量就达到暴雨标准;少部分是稳定的层状云降水,雨强中等,维持时间长而达到暴雨标准.据1983—1988年4—6月109个样本统计,在前一种强降水暴雨样本中,约有四分之三强降水开始之前能在我省以西的上游地区见到对流云团和对应地面图上有强降水.江西以西的上 相似文献
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利用常规观测资料和气象卫星、自动站、加密雨量站资料等,对2008年5月3日湖北省孝感市一次大暴雨天气过程进行诊断分析.结果表明,中尺度辐合是造成此次过程第一段强降水的主要原因,西风槽、西南涡和低空西南急流是其第二段强降水的主要影响系统;温度露点差<4 ℃、K指数≥36 ℃、△θse700-850<0 ℃与两段暴雨过程存在较好的对应关系;整个过程主要是3个中尺度对流云团活动所致,云团具有明显的中尺度特征;地面中尺度辐合线的强度变化及其移动,与两段强降水的强度及落时、落区变化有较好的对应关系. 相似文献
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2004年7月18～21日暴雨过程的中尺度对流云团特征 总被引：3，自引：0，他引：3
分析2004年7月18-21日广西暴雨过程中尺度对流云团发展的大尺度动力、热力背景和卫星云图的TBB特征。结果表明：低涡切变是强降水的重要天气系统，西风带的冷空气加入对中尺度云团的发展至关重要，它有利于形成强降水天气发生的斜压不稳定区；暴雨强度与中尺度云团的最冷云区亮温和面积密切相关，强降水出现在对流云团的发展阶段，云团下风方和≤-70℃的冷云覆盖区与暴雨落区有较好的对应关系。 相似文献
6.
从雷达回波,卫星云图,雨团等方面分析了“９８．７”暴雨过程。发现;近于垂直的中低层切变线是对流云团产生的主要动力条件。云图上中尺度云团东移过程中的加强,合并和减弱过程与对流云团的新生,发展和消亡阶段相对应。强降水与雷达回波上强单体的稳定维持相关,雨团与中尺度云团有很好的对应关系。 相似文献
7.
本文利用实况探空资料和风云2C、2D卫星探测资料,对2014年7月西太平洋副高与西风带低槽共同作用下长江流域出现的三次暴雨过程进行分析,将三次过程卫星云图以及各种物理要素场配置进行对比,得到以下结论。云系表现为典型的梅雨锋云系特征,云系位于高空槽前580线与副高外围588线之间。降水云带由对流云团、稳定性降水云团及混合性降水云带三部分组成。梅雨锋中的MCC云团十分活跃。随着云团最强对流的逐渐减弱,云团面积迅速膨胀,并持续数小时后很快减小,强降水主要发生在云团发展和成熟期中。强降水还与对流有关,降水强度总体上跟TBB强度呈反相关,TBB越低降水越强。梅雨锋云系的分布与各层的垂直速度场、涡度场、散度场有很好的对应关系,与中高层的涡度平流场也有较好的对应关系,云带总体位置与上升运动区、低层辐合和高层辐散区、正涡度平流区位置近乎重叠。比湿通量、比湿通量散度和假相当位温等温湿参量的分布特征能很好锋面云带的移动、发展和分布特征。 相似文献
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西北地区东部一次持续性暴雨的成因分析 总被引：6，自引：2，他引：4
分析了西北地区东部一次副高西北侧西南气流型的暴雨过程.结果表明,这次暴雨是中α和中β尺度对流云团引发的强对流性降水.青藏高原云团移到川西北后出现更新,老云团消亡时在其前方有新云团生成.冷锋云带到达甘肃河东地区后,其前缘也触发对流云团,受四川盆地强水汽输送带影响,新云团一般生成在水汽输送带左侧.强雨区产生在冷锋云带与对流云团结合时,对流云团的发展是水汽输送及天气系统辐合和有利的局地环境条件如双层对流不稳定加地形等多因子综合作用的结果.区域性暴雨出现在冷锋云带与对流云团叠加区,这里降水效率高.强雨区大多位于对流云团的西北或东北部与冷锋云带结合处. 相似文献
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一次引发强降水的热带低压对流云团的多尺度特征分析 总被引：2，自引：0，他引：2
利用每10分种一次地面自动站常规观测资料，以及每5分钟一次多普勒天气雷达和每小时一次卫星等非常规资料，对一次造成上海地区特大暴雨的热带低压对流云团的多尺度特征进行分析，取得主要结果：（1） 本次暴雨过程由三次强降水造成，每次强降水都由?和?中尺度雨团构成，表明引发强降水的热带低压对流云团内部的多尺度特征；（2） 热带低压对流云团在上海地区的维持和加强是由其移动方向右后侧的?和?中尺度对流单体不断新生、发展和合并的结果，这一过程对应于雷达强回波带的新生、发展和合并现象；（3） 自动站风场分析出中尺度辐合线的位置和强度与中尺度雨团的落区和强度对应，雷达基本反射率和径向风资料进一步证实了气流辐合区是对流单体生成的区域。 相似文献
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利用自动气象观测站降水资料、常规地面与高空观测资料及卫星云图资料,对2012—2017年6—10月金沙江乌东德水电站坝区18次暴雨个例的大尺度环流背景及卫星云图演变特征进行统计分析,结果表明,切变冷锋型、两高辐合型、西南涡型、孟加拉湾风暴型、切变线型和高空槽型是金沙江乌东德水电站坝区的六类暴雨概念模型。总结归纳出对应的六类典型云型：切变线云带前界处的对流云团8次(占44.4%)、两高辐合云区内部的对流云团4次(占22.2%)、西南涡西南或东南象限的对流云团2次(占11.1%)、孟加拉湾风暴涡旋云系中分离出来的对流云团或对流云系2次(占11.1%)、切变线云带内部的对流云团1次(占5.6%)、高空槽前盾状卷云区南端的对流云系1次(占5.6%)。 相似文献
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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
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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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Various features of the atmospheric environment affect the number of migratory insects, besides their initial population. However, little is known about the impact of atmospheric low-frequency oscillation(10 to 90 days) on insect migration. A case study was conducted to ascertain the influence of low-frequency atmospheric oscillation on the immigration of brown planthopper, Nilaparvata lugens(Stl), in Hunan and Jiangxi provinces. The results showed the following:(1) The number of immigrating N. lugens from April to June of 2007 through 2016 mainly exhibited a periodic oscillation of 10 to 20 days.(2) The 10-20 d low-frequency number of immigrating N. lugens was significantly correlated with a low-frequency wind field and a geopotential height field at 850 h Pa.(3) During the peak phase of immigration, southwest or south winds served as a driving force and carried N. lugens populations northward, and when in the back of the trough and the front of the ridge, the downward airflow created a favorable condition for N. lugens to land in the study area. In conclusion, the northward migration of N. lugens was influenced by a low-frequency atmospheric circulation based on the analysis of dynamics. This study was the first research connecting atmospheric low-frequency oscillation to insect migration. 相似文献
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The atmospheric and oceanic conditions before the onset of EP El Ni?o and CP El Ni?o in nearly 30 years are compared and analyzed by using 850 hPa wind, 20℃ isotherm depth, sea surface temperature and the Wheeler and Hendon index. The results are as follows: In the western equatorial Pacific, the occurrence of the anomalously strong westerly winds of the EP El Ni?o is earlier than that of the CP El Ni?o. Its intensity is far stronger than that of the CP El Ni?o. Two months before the El Ni?o, the anomaly westerly winds of the EP El Ni?o have extended to the eastern Pacific region, while the westerly wind anomaly of the CP El Ni?o can only extend to the west of the dateline three months before the El Ni?o and later stay there. Unlike the EP El Ni?o, the CP El Ni?o is always associated with easterly wind anomaly in the eastern equatorial Pacific before its onset. The thermocline depth anomaly of the EP El Ni?o can significantly move eastward and deepen. In addition, we also find that the evolution of thermocline is ahead of the development of the sea surface temperature for the EP El Ni?o. The strong MJO activity of the EP El Ni?o in the western and central Pacific is earlier than that of the CP El Ni?o. Measured by the standard deviation of the zonal wind square, the intensity of MJO activity of the EP El Ni?o is significantly greater than that of the CP El Ni?o before the onset of El Ni?o. 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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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
18.
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
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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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