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1.
李海红  戴升 《气象》2000,26(10):53-55
对1980 ̄1999年造成青藏高原东部17次大到暴雨天气过程的卫星云图演变特征及1999年9月9 ̄10日出现的大到暴雨过程形成的物理量场进行了分析,总结出形成暴雨云带的影响系统模型和物理量场变化规律,对预报高原暴雨天气有一定的参考价值。  相似文献   

2.
李海红  戴升  史津梅  裴少阳 《气象》2000,26(10):53-55
对 1 98 0~ 1 999年造成青藏高原东部 1 7次大到暴雨天气过程的卫星云图演变特征及 1 999年 9月 9~ 1 0日出现的大到暴雨过程形成的物理量场进行了分析 ,总结出形成暴雨云带的影响系统模型和物理量场变化规律 ,对预报高原暴雨天气有一定的参考价值。  相似文献   

3.
利用较高分辨率的非静力中尺度数值模式MM 5和NECP资料,对2003-08-28西北东部致洪暴雨天气过程进行数值模拟,重点研究α、β中尺度系统的发生发展和演变过程,对影响暴雨的物理量诊断分析。结果表明:α中尺度低涡越山后迅速生成发展,在有利背景条件下生成多个β中尺度系统,不同尺度系统共同作用形成本次区域性暴雨。强降水主要出现在低涡系统的发展阶段。暴雨区南侧600 hPa附近存在干冷层,上部大气层结稳定,抑制垂直扩散,有利于水汽和能量沿着低空向雨区集中输送。暴雨区上空水汽和能量以垂直输送为主,同时伴有大量潜能释放。位涡、散度、垂直速度等物理量的空间分布,有利于强对流天气发生。  相似文献   

4.
“8.19”西北东部大到暴雨诊断分析和数值模拟   总被引:8,自引:1,他引:8  
利用MICAPS系统T213资料、NCEP再分析资料及实况观测资料,对2004年8月19日发生在西北地区东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发现:这次暴雨天气过程中西太平洋副热带高压有一次明显的西伸,是一次较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和孟加拉湾,中低层的水汽输送十分充沛,并在甘肃河东和宁夏形成辐合。运用三重嵌套的中尺度数值预报模式MM5,对这次暴雨过程进行了两种方案的高分辨率数值模拟,结果表明,运用四维资料同化后的方案在形势和降水预报方面优于未进行资料同化的方案。  相似文献   

5.
2003-10-09-13渭河流域出现连阴雨,其中10日关中东部出现大到暴雨。利用高空资料和T213数值预报产品进行天气学和物理量场特征分析。表明这次强降水过程的热力、水汽以及动力条件在连阴雨一开始时就已经具备,同时配合有一个中尺度天气系统的生消过程。T213各种产品对大降水的预报能力增强,特别是物理量预报对大降水落区预报有较好的指示意义。  相似文献   

6.
本文利用探测资料和数值预报产品从天气形势、物理量场配置和卫星云图的演变特征等方面对2003年7月29日夜间到30日白天青海境内的大到暴雨降水天气过程和预报进行了分析。结果表明:南部暖湿气流向北输送与西风带低槽分裂东移的冷空气在青海东北部交绥是造成这次大到暴雨的主要原因,西宁单站高空特性层层数持续增多、大多数等压面层湿度显著增加是这次大到暴雨天气产生的前兆。  相似文献   

7.
利用常规气象观测资料和卫星资料,对2009年8月17-18日青海东北部区域性大到暴雨天气的环流背景、涡度场、水汽条件诊断、中尺度系统特征进行了分析,结果表明:这次暴雨天气的形成除了有利的大尺度环流背景外暴雨区上空还提供了水汽的低层辐合、高层辐散、上升运动等环境条件;卫星云图上中尺度对流系统(MCS)的发展与大到暴雨相关密切,其中TMG(相当黑体亮温)大值区的分布对大到暴雨落区预报有一定指示意义。  相似文献   

8.
何光碧  陈忠明 《高原气象》2004,23(Z1):15-22
利用MM5中尺度模式,对2003年8月8~10日发生在四川盆地的一次强降水过程进行了数值模拟.结果表明(1)MM5模式准确地预报出盆地西北部大暴雨过程,在降水的中心强度和位置预报上非常接近实况.(2)盆地不稳定能量聚集是本次暴雨产生的内在条件,冷暖空气交汇是本次暴雨发生的触发因子,源源不断的水汽输送和冷平流输送,以及中尺度涡旋区辐合上升运动与正涡度耦合有利于低值系统的发生、发展和维持,从而导致该地区强降水.(3)MM5中尺度模式在高原东侧陡坡地形区域具有业务应用前景.  相似文献   

9.
台风低压暴雨的中尺度特征分析   总被引:1,自引:0,他引:1  
通过对淇、卫河流域“82·8”、“96·8”两场台风低压暴雨的物理量资料合成分析,揭示了该流域致洪暴雨天气的形势场、水汽场、动力场的中尺度特征。  相似文献   

10.
"8·19"甘肃区域暴雨的特征分析及数值模拟   总被引:8,自引:3,他引:8  
分析了“8.19”甘肃区域暴雨发生的天气气候背景,不同层次的环流特征;重点分析了不同物理量场的变化,云系的演变;应用MM5中尺度非静力模式模拟了暴雨过程,并对模拟结果进行了分析。结果表明:“8.19”甘肃区域暴雨除了有利的天气系统配置外,低层强烈的风场辐合是导致暴雨的重要原因。强雨带的移动滞后于云顶温度最低的强对流云带;MM5对降水过程的强度、落区有较好的预报能力,尤其是12~48 h的预报效果相对最好,对强降水天气预报有较好的指示意义。  相似文献   

11.
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 Nio3.4 index in summer and autumn but negatively correlated in spring and winter.  相似文献   

12.
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   

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.
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   

15.
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(Stl), 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   

16.
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   

17.
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   

18.
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   

19.
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   

20.
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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