Based on the data of national observation stations of CMISS system,artificial encrypted observation data of snow depth,ERA5 reanalysis data,the snowfall process in Ulanqab City from March 17 to 19,2022 was analyzed.It...Based on the data of national observation stations of CMISS system,artificial encrypted observation data of snow depth,ERA5 reanalysis data,the snowfall process in Ulanqab City from March 17 to 19,2022 was analyzed.It is found that the influencing system of the snowfall process was upper-air trough combined with ground inverted trough.Snowfall was not proportional to snow depth,and the relationship between the maximum snow depth and total snowfall varied in different value intervals.A large intensity of snowfall was a necessary condition for the formation of abundant accumulated snow when ground temperature was higher than 0℃.After the formation of accumulated snow,ground temperature changed less,and it was easy to produce accumulated snow as ground temperature was lower.The lower the temperature,the more conducive to the generation of accumulated snow.展开更多
Based on the observation data of meteorological stations,Doppler radar observation data of Ulanqab City,and ERA-5 reanalysis data,a snowstorm process in Ulanqab City from March 17 to 18,2022 was analyzed.The results s...Based on the observation data of meteorological stations,Doppler radar observation data of Ulanqab City,and ERA-5 reanalysis data,a snowstorm process in Ulanqab City from March 17 to 18,2022 was analyzed.The results show that this was a type Ⅱ snowstorm process generated under the joint influence of upper trough and ground low inverted trough and frontal cyclone.The main period of snowfall can be divided into two time stages,and the total snowfall was more in the south and less in the north,which was consistent with that of average specific humidity field.Water vapor conditions provided by strong water vapor transport and convergence,strong upward movement shown by large vertical velocity field,and the suction action of high-and low-layer divergence and convergence were the reasons for the hourly heavy snowfall on the 18^(th).During the process,radar echoes were mainly sheet-shaped,and composite reflectivity was 15-25 dBZ in most areas.The zero speed line in the first period was positively"S"-shaped,and there was warm advection and southwest wind.On the morning of the 18^(th),after the cold front transited the city,Ulanqab City was gradually controlled by northwest wind,and the snow tended to end.展开更多
In November 2021, Northeast China had more precipitation than in the same period. Among them, Heilongjiang and Jilin provinces in the Northeast China were the highest precipitation in the same period. I study a snowfa...In November 2021, Northeast China had more precipitation than in the same period. Among them, Heilongjiang and Jilin provinces in the Northeast China were the highest precipitation in the same period. I study a snowfall weather process from November 5 to 9, which mainly includes dynamic situation, synoptic background and situation. The results show that: In the middle and high latitudes of Eurasia, circulation is adjusted from zonal to meridional with large fluctuations. The northerly wind behind the trough continuously transports the polar cold air to the south. The northwest airflow behind the trough led the cold air to erupt to the southeast. In the process of moving southward, the cold air meets the warm and humid air in front of the trough, causing snowfall in the northeast. The southerly airflow and southeasterly airflow on the east side of the vortex continued to transport warm and humid airflow from the Yellow Sea and the Sea of Japan, which enhanced the snowfall.展开更多
On July 10,2004,Beijing was hit by the rainstorm that has not been seen for many years,which caused water accumulation in many places of the urban area,power supply interruption in many places,and traffic paralysis fo...On July 10,2004,Beijing was hit by the rainstorm that has not been seen for many years,which caused water accumulation in many places of the urban area,power supply interruption in many places,and traffic paralysis for nearly 5 h. On July 12,2004,the rainstorm in Shanghai lasted less than 1 h,but it caused 7 deaths,more than 20 injuries,extensive power outages and traffic paralysis. At the end of 2005,the continuous snowfall in Weihai City of Shandong Province for half a month caused direct economic losses of over 200 million yuan,and the continuous heavy snowfall had a serious impact on people’s lives. From July 17 to 23,2021,Henan Province suffered a rare extremely heavy rainstorm in history,with a direct economic loss of 120.6 billion yuan. Faced with such urban meteorological disasters and other types of urban disasters,combined with the current situation of disaster prevention and reduction in China,what will managers,decision-makers,and experts and scholars think about from them.展开更多
利用常规观测、积雪深度逐时加密观测资料和欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)第五代大气再分析(ECMWF Reanalysis v5,ERA5)资料,对2023年12月13—15日山东一次极端暴雪天气过程积雪特...利用常规观测、积雪深度逐时加密观测资料和欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)第五代大气再分析(ECMWF Reanalysis v5,ERA5)资料,对2023年12月13—15日山东一次极端暴雪天气过程积雪特征及其成因进行分析,得到以下结论:(1)此次过程是一次江淮气旋暴雪天气过程,具有持续时间长、降水相态复杂、基础温度低、降温幅度大和积雪深度厚等特征。(2)最大小时新增积雪深度可达8 cm;过程平均雪水比为0.7 cm·mm^(-1),呈“西大东小”的分布特征。(3)有积雪的站近地面温度从开始降雪到地面产生积雪,气温和雪面温度均呈下降趋势,0 cm地温在降雪前期降温明显,积雪形成后地温不再明显变化。无积雪的站在整个降雪时段内近地面温度可分为4种情况。(4)雪水比随气温变化最明显;积雪形成之后地温对雪水比大小影响不大;当雪水比小于0.75 cm·mm^(-1)时,雪水比随雪面温度降低而增大,当雪水比大于0.76 cm·mm^(-1)后,雪面温度不再有明显变化。展开更多
利用常规气象观测资料、降水天气现象仪资料、美国国家海洋和大气管理局(National Oceanic and Atmospheric Administration,NOAA)资料、欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)第五代大气再...利用常规气象观测资料、降水天气现象仪资料、美国国家海洋和大气管理局(National Oceanic and Atmospheric Administration,NOAA)资料、欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)第五代大气再分析(ECMWF Reanalysis v5,ERA5)资料等对2023年12月山东半岛的海效应特大暴雪和2005年12月持续性海效应强降雪过程的高空形势、海气温差、低层切变线、大气水凝物等进行了综合分析。结果表明:(1)亚欧大陆强大的经向高压脊和脊前冷涡环流是发生海效应暴雪的大尺度环流背景。2005年高压脊宽广、稳定少动是海效应强降雪持续时间长的主要原因,2023年高压脊、冷涡的经向特征更加显著,冷空气爆发力强。(2)2005、2023年渤海海面温度较常年偏高;2023年偏高2.5℃的范围更广,12月20—21日海气温差超过30℃。(3)出现暴雪时,山东半岛北部存在偏西风和北—东北风之间的风场辐合;荣成站出现暴雪时,低层需要更强劲的引导气流。(4)2023年12月20—21日,云体主要由冰晶和雪晶构成,较多雪晶位于上升气流上方,与冰粒子分布区域重叠,说明除了水汽凝华外,冰雪晶粒子之间的聚合作用对雪粒子的增长有很大帮助,聚合产生的枝状雪粒子有利于积雪深度增大,文登站雨滴谱也表明,21—22日雪粒子直径偏大的特征更明显。展开更多
The horizontal distribution and levels of heavy metals in the biggest snowstorm in Shenyang since 1904 were investigated by analyzing 4 metals (As,Cd,Pb,and Cu) in a series of ultraclean samples collected from 17 site...The horizontal distribution and levels of heavy metals in the biggest snowstorm in Shenyang since 1904 were investigated by analyzing 4 metals (As,Cd,Pb,and Cu) in a series of ultraclean samples collected from 17 sites distributed in different regions of the Shenyang area,China.The results showed that the concentrations of all the 4 heavy metals in snow from the industrial regions were high,up to 7.3 (As),2.2 (Cd),850.0 (Pb),and 0.197-20.2 (Cu)μg/kg,respectively.In the suburb,in contrast,their concentration...展开更多
The energetics of the third stage of a snowstorm over China was analyzed using ECWMF data.The analysis of the energy budget for the Middle East trough and the western Pacific trough that developed toward China on 25-2...The energetics of the third stage of a snowstorm over China was analyzed using ECWMF data.The analysis of the energy budget for the Middle East trough and the western Pacific trough that developed toward China on 25-28 January 2008 showed the advection of the geopotential by the ageostrophic wind to be both a crucial source and the primary sink of the eddy kinetic energy centers associated with the troughs.The magnitudes of the energy conversion terms,interaction kinetic energy conversion and baroclinic conversion,were too small to explain the development of the energy centers and the jet streaks.The energy centers gained energy at their entrance regions via the convergence of the ageostrophic geopotential fluxes,and then lost energy at their exit regions by the same fluxes.At the entrance regions,the fluxes converged,increasing the geopotential gradient,which generated a stronger geostrophic wind and higher kinetic energy,resulting in an ascending motion in this area.When the troughs moved to China,the ascending motion caused by the convergence of the fluxes at entrance region intensified the snowstorms over central and southern China.展开更多
文摘Based on the data of national observation stations of CMISS system,artificial encrypted observation data of snow depth,ERA5 reanalysis data,the snowfall process in Ulanqab City from March 17 to 19,2022 was analyzed.It is found that the influencing system of the snowfall process was upper-air trough combined with ground inverted trough.Snowfall was not proportional to snow depth,and the relationship between the maximum snow depth and total snowfall varied in different value intervals.A large intensity of snowfall was a necessary condition for the formation of abundant accumulated snow when ground temperature was higher than 0℃.After the formation of accumulated snow,ground temperature changed less,and it was easy to produce accumulated snow as ground temperature was lower.The lower the temperature,the more conducive to the generation of accumulated snow.
文摘Based on the observation data of meteorological stations,Doppler radar observation data of Ulanqab City,and ERA-5 reanalysis data,a snowstorm process in Ulanqab City from March 17 to 18,2022 was analyzed.The results show that this was a type Ⅱ snowstorm process generated under the joint influence of upper trough and ground low inverted trough and frontal cyclone.The main period of snowfall can be divided into two time stages,and the total snowfall was more in the south and less in the north,which was consistent with that of average specific humidity field.Water vapor conditions provided by strong water vapor transport and convergence,strong upward movement shown by large vertical velocity field,and the suction action of high-and low-layer divergence and convergence were the reasons for the hourly heavy snowfall on the 18^(th).During the process,radar echoes were mainly sheet-shaped,and composite reflectivity was 15-25 dBZ in most areas.The zero speed line in the first period was positively"S"-shaped,and there was warm advection and southwest wind.On the morning of the 18^(th),after the cold front transited the city,Ulanqab City was gradually controlled by northwest wind,and the snow tended to end.
文摘In November 2021, Northeast China had more precipitation than in the same period. Among them, Heilongjiang and Jilin provinces in the Northeast China were the highest precipitation in the same period. I study a snowfall weather process from November 5 to 9, which mainly includes dynamic situation, synoptic background and situation. The results show that: In the middle and high latitudes of Eurasia, circulation is adjusted from zonal to meridional with large fluctuations. The northerly wind behind the trough continuously transports the polar cold air to the south. The northwest airflow behind the trough led the cold air to erupt to the southeast. In the process of moving southward, the cold air meets the warm and humid air in front of the trough, causing snowfall in the northeast. The southerly airflow and southeasterly airflow on the east side of the vortex continued to transport warm and humid airflow from the Yellow Sea and the Sea of Japan, which enhanced the snowfall.
文摘On July 10,2004,Beijing was hit by the rainstorm that has not been seen for many years,which caused water accumulation in many places of the urban area,power supply interruption in many places,and traffic paralysis for nearly 5 h. On July 12,2004,the rainstorm in Shanghai lasted less than 1 h,but it caused 7 deaths,more than 20 injuries,extensive power outages and traffic paralysis. At the end of 2005,the continuous snowfall in Weihai City of Shandong Province for half a month caused direct economic losses of over 200 million yuan,and the continuous heavy snowfall had a serious impact on people’s lives. From July 17 to 23,2021,Henan Province suffered a rare extremely heavy rainstorm in history,with a direct economic loss of 120.6 billion yuan. Faced with such urban meteorological disasters and other types of urban disasters,combined with the current situation of disaster prevention and reduction in China,what will managers,decision-makers,and experts and scholars think about from them.
文摘利用常规气象观测资料、降水天气现象仪资料、美国国家海洋和大气管理局(National Oceanic and Atmospheric Administration,NOAA)资料、欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)第五代大气再分析(ECMWF Reanalysis v5,ERA5)资料等对2023年12月山东半岛的海效应特大暴雪和2005年12月持续性海效应强降雪过程的高空形势、海气温差、低层切变线、大气水凝物等进行了综合分析。结果表明:(1)亚欧大陆强大的经向高压脊和脊前冷涡环流是发生海效应暴雪的大尺度环流背景。2005年高压脊宽广、稳定少动是海效应强降雪持续时间长的主要原因,2023年高压脊、冷涡的经向特征更加显著,冷空气爆发力强。(2)2005、2023年渤海海面温度较常年偏高;2023年偏高2.5℃的范围更广,12月20—21日海气温差超过30℃。(3)出现暴雪时,山东半岛北部存在偏西风和北—东北风之间的风场辐合;荣成站出现暴雪时,低层需要更强劲的引导气流。(4)2023年12月20—21日,云体主要由冰晶和雪晶构成,较多雪晶位于上升气流上方,与冰粒子分布区域重叠,说明除了水汽凝华外,冰雪晶粒子之间的聚合作用对雪粒子的增长有很大帮助,聚合产生的枝状雪粒子有利于积雪深度增大,文登站雨滴谱也表明,21—22日雪粒子直径偏大的特征更明显。
文摘The horizontal distribution and levels of heavy metals in the biggest snowstorm in Shenyang since 1904 were investigated by analyzing 4 metals (As,Cd,Pb,and Cu) in a series of ultraclean samples collected from 17 sites distributed in different regions of the Shenyang area,China.The results showed that the concentrations of all the 4 heavy metals in snow from the industrial regions were high,up to 7.3 (As),2.2 (Cd),850.0 (Pb),and 0.197-20.2 (Cu)μg/kg,respectively.In the suburb,in contrast,their concentration...
基金supported by the National Basic Research Project of China (Grant Nos. 2013CB430105 and 2012CB417201)the National Natural Science Foundation of China (Grant No. 40930950)+1 种基金the Chinese Academy of Meteorological Sciences State Key Laboratory of Severe Weather (LaSW) (Grant No. 2011LASW-A01)the Key Research Program of the Sciences (Grant No. KZZDEW-05-01)
文摘The energetics of the third stage of a snowstorm over China was analyzed using ECWMF data.The analysis of the energy budget for the Middle East trough and the western Pacific trough that developed toward China on 25-28 January 2008 showed the advection of the geopotential by the ageostrophic wind to be both a crucial source and the primary sink of the eddy kinetic energy centers associated with the troughs.The magnitudes of the energy conversion terms,interaction kinetic energy conversion and baroclinic conversion,were too small to explain the development of the energy centers and the jet streaks.The energy centers gained energy at their entrance regions via the convergence of the ageostrophic geopotential fluxes,and then lost energy at their exit regions by the same fluxes.At the entrance regions,the fluxes converged,increasing the geopotential gradient,which generated a stronger geostrophic wind and higher kinetic energy,resulting in an ascending motion in this area.When the troughs moved to China,the ascending motion caused by the convergence of the fluxes at entrance region intensified the snowstorms over central and southern China.
