受登陆北上台风“利奇马”等影响,2019年8月9~12日山东省出现连续暴雨,其中10日夜间出现降雨峰值。利用中国气象局上海台风研究所(Shanghai Typhoon Institute of China Meteorological Administration,简称CMA-STI)热带气旋最佳路径数...受登陆北上台风“利奇马”等影响,2019年8月9~12日山东省出现连续暴雨,其中10日夜间出现降雨峰值。利用中国气象局上海台风研究所(Shanghai Typhoon Institute of China Meteorological Administration,简称CMA-STI)热带气旋最佳路径数据、山东省自动气象站逐时降雨量、常规观测资料、中国风云二号地球静止气象卫星(FY-2G)0.1°×0.1°逐小时云顶相当黑体亮温和美国环境预报中心(National Center of Environmental Prediction,简称NCEP)1°×1°逐6 h再分析等资料,主要运用纬向风局地变化方程与大气动能方程,诊断分析降雨明显增幅与高、低层风场变化的关系。结果表明:(1)暴雨主要影响系统有高低空急流、500 hPa西风槽、850 hPa台风倒槽及“利奇马”本体环流等。10日200 hPa中纬度大尺度西南风急流东南移影响鲁西北,当天08:00(北京时,下同)850 hPa因双台风活动而形成的大尺度东南风急流突然北伸越过山东省。台风倒槽对流云与本体环流对流云先、后北移经鲁中,累积效应造成该地区10日夜间雨量最大。(2)10日20:00850 hPa章丘站东北侧出现了过程最快东风增幅,纬向运动方程诊断结果表明,东风平流是东风增加最主要原因,地转偏向力项则不利于东风增加。(3)10日20:00章丘站200 hPa西南风风力明显加大形成急流,10日08:00至11日08:00青岛站850 hPa维持东南风低空急流。同时位于高空急流右后侧与低空急流左前方是鲁中附近10日夜间降雨增幅的重要原因。章丘200 hPa与青岛850 hPa都是在最大风力之前12 h动能增加最快。动能方程诊断表明,最有利于鲁西北高空急流形成的是位能平流项,最有利于鲁东南低空急流形成的是动能垂直通量散度项。(4)10日20:00至13日08:00“利奇马”本体环流一直在影响山东,暴雨期间山东中部地形的动力作用也一直存在,而降雨的峰值是出现在10日夜间,说明10日20:00前后高、低空急流的耦合可能是山东暴雨增幅的主要影响因子。其主要作用至少有加强山东中部的垂直运动、整层水汽输送与静力不稳定度等方面。展开更多
The goal of this paper is to quantitatively formulate some necessary conditions for the development of intense atmospheric vortices. Specifically, these criteria are discussed for tropical cyclones （TC） and polar lo...The goal of this paper is to quantitatively formulate some necessary conditions for the development of intense atmospheric vortices. Specifically, these criteria are discussed for tropical cyclones （TC） and polar lows （PL） by using bulk formulas for fluxes of momentum, sensible heating, and latent heating between the ocean and the atmosphere. The velocity scale is used in two forms： （1） as expressed through the buoyancy flux b and the Coriolis parameter Ic for rotating fluids convection, and （2） as expressed with the cube of velocity times the drag coefficient through the formula for total kinetic energy dissipation in the atmospheric boundary layer. In the quasistationary case the dissipation equals the generation of the energy. In both cases the velocity scale can be expressed through temperature and humidity differences between the ocean and the atmosphere in terms of the reduced gravity, and both forms produce quite comparable velocity scales. Using parameters b and Ic, we can form scales of the area and, by adding the mass of a unit air column, a scale of the total kinetic energy as well. These scales nicely explain the much smaller size of a PL, as compared to a TC, and the total kinetic energy of a TC is of the order 1018 - 1019 J. It will be shown that wind of 33 m s^-1 is produced when the total enthalpy fluxes between the ocean and the atmosphere are about 700 W m-2 for a TC and 1700 W m-2 for a PL, in association with the much larger role of the latent heat in the first case and the stricter geostrophic constraints and larger static stability in the second case. This replaces the mystical role of 26℃ as a criterion for TC origin. The buoyancy flux, a product of the reduced gravity and the wind speed, together with the atmospheric static stability, determines the rate of the penetrating convection. It is known from the observations that the formation time for a PL reaching an altitude of 5-6 km can be only a few hours, and a day, or even half a day, for a TC reaching 15-18 km. These two facts allow us to construct curves on the plane of Ts and ΔT = Ts - Ta to determine possibilities for forming an intense vortex. Here, Ta is the atmospheric temperature at the height z = 10 m. A PL should have AT 〉 20℃ in accordance with the observations and nmnerical simulations. The conditions for a TC are not so straightforward but our diagram shows that the temperature difference of a few degrees, or possibly even a fraction of a degree, might be sufficient for TC development for a range of static stabilities and development times.展开更多
Based on multiple kinds of observation data and NCEP/NCAR reanalysis data,the circulation background,cloud clusters and radar characteristics of a rainstorm far from the typhoon " Haitang" in Lianyungang,Jia...Based on multiple kinds of observation data and NCEP/NCAR reanalysis data,the circulation background,cloud clusters and radar characteristics of a rainstorm far from the typhoon " Haitang" in Lianyungang,Jiangsu on the morning of July 31,2017 were analyzed,and causes of convection were discussed from the aspects of dynamic,thermal and water vapor conditions. The results showed that the rainstorm process was caused by convection cells with low center of mass,and strong convection mainly occurred in a position where temperature gradient at cloud top was the largest. In North China at 850 hP a,eastern cold air on the south side of anticyclonic circulation moved southwards and joined southeast air flow on the periphery of typhoon,which was the main reason for the occurrence of convection. The circulation of upper-level divergence and lowerlevel convergence was beneficial to the maintaining of convection. The convergence of southeast wind speed on the periphery of typhoon made water vapor accumulate,thereby providing enough water vapor for the appearance of heavy rainfall. K index had good denotative meaning to convection activity,and the process of convection with weak Cape value needs to be paid special attention to in business. The prediction effect of rainfall distribution and areas by the models EC and ECRC was superior to other models.展开更多
文摘受登陆北上台风“利奇马”等影响,2019年8月9~12日山东省出现连续暴雨,其中10日夜间出现降雨峰值。利用中国气象局上海台风研究所(Shanghai Typhoon Institute of China Meteorological Administration,简称CMA-STI)热带气旋最佳路径数据、山东省自动气象站逐时降雨量、常规观测资料、中国风云二号地球静止气象卫星(FY-2G)0.1°×0.1°逐小时云顶相当黑体亮温和美国环境预报中心(National Center of Environmental Prediction,简称NCEP)1°×1°逐6 h再分析等资料,主要运用纬向风局地变化方程与大气动能方程,诊断分析降雨明显增幅与高、低层风场变化的关系。结果表明:(1)暴雨主要影响系统有高低空急流、500 hPa西风槽、850 hPa台风倒槽及“利奇马”本体环流等。10日200 hPa中纬度大尺度西南风急流东南移影响鲁西北,当天08:00(北京时,下同)850 hPa因双台风活动而形成的大尺度东南风急流突然北伸越过山东省。台风倒槽对流云与本体环流对流云先、后北移经鲁中,累积效应造成该地区10日夜间雨量最大。(2)10日20:00850 hPa章丘站东北侧出现了过程最快东风增幅,纬向运动方程诊断结果表明,东风平流是东风增加最主要原因,地转偏向力项则不利于东风增加。(3)10日20:00章丘站200 hPa西南风风力明显加大形成急流,10日08:00至11日08:00青岛站850 hPa维持东南风低空急流。同时位于高空急流右后侧与低空急流左前方是鲁中附近10日夜间降雨增幅的重要原因。章丘200 hPa与青岛850 hPa都是在最大风力之前12 h动能增加最快。动能方程诊断表明,最有利于鲁西北高空急流形成的是位能平流项,最有利于鲁东南低空急流形成的是动能垂直通量散度项。(4)10日20:00至13日08:00“利奇马”本体环流一直在影响山东,暴雨期间山东中部地形的动力作用也一直存在,而降雨的峰值是出现在10日夜间,说明10日20:00前后高、低空急流的耦合可能是山东暴雨增幅的主要影响因子。其主要作用至少有加强山东中部的垂直运动、整层水汽输送与静力不稳定度等方面。
基金the grant of the RF President SS4166 2006.5the Program of the Presidium of RAS"Mathematical Methods of Nonlinear Dynamics"
文摘The goal of this paper is to quantitatively formulate some necessary conditions for the development of intense atmospheric vortices. Specifically, these criteria are discussed for tropical cyclones （TC） and polar lows （PL） by using bulk formulas for fluxes of momentum, sensible heating, and latent heating between the ocean and the atmosphere. The velocity scale is used in two forms： （1） as expressed through the buoyancy flux b and the Coriolis parameter Ic for rotating fluids convection, and （2） as expressed with the cube of velocity times the drag coefficient through the formula for total kinetic energy dissipation in the atmospheric boundary layer. In the quasistationary case the dissipation equals the generation of the energy. In both cases the velocity scale can be expressed through temperature and humidity differences between the ocean and the atmosphere in terms of the reduced gravity, and both forms produce quite comparable velocity scales. Using parameters b and Ic, we can form scales of the area and, by adding the mass of a unit air column, a scale of the total kinetic energy as well. These scales nicely explain the much smaller size of a PL, as compared to a TC, and the total kinetic energy of a TC is of the order 1018 - 1019 J. It will be shown that wind of 33 m s^-1 is produced when the total enthalpy fluxes between the ocean and the atmosphere are about 700 W m-2 for a TC and 1700 W m-2 for a PL, in association with the much larger role of the latent heat in the first case and the stricter geostrophic constraints and larger static stability in the second case. This replaces the mystical role of 26℃ as a criterion for TC origin. The buoyancy flux, a product of the reduced gravity and the wind speed, together with the atmospheric static stability, determines the rate of the penetrating convection. It is known from the observations that the formation time for a PL reaching an altitude of 5-6 km can be only a few hours, and a day, or even half a day, for a TC reaching 15-18 km. These two facts allow us to construct curves on the plane of Ts and ΔT = Ts - Ta to determine possibilities for forming an intense vortex. Here, Ta is the atmospheric temperature at the height z = 10 m. A PL should have AT 〉 20℃ in accordance with the observations and nmnerical simulations. The conditions for a TC are not so straightforward but our diagram shows that the temperature difference of a few degrees, or possibly even a fraction of a degree, might be sufficient for TC development for a range of static stabilities and development times.
基金Supported by Science and Technology Planning Project of Lianyungang Meteorological Bureau(LG201604,LG201602)Project of Lianyungang Science and Technology Bureau(SH1634,SH1422)Founds for Science and Technology Innovation Team of Marine Forecasting of Lianyungang Meteorological Bureau
文摘Based on multiple kinds of observation data and NCEP/NCAR reanalysis data,the circulation background,cloud clusters and radar characteristics of a rainstorm far from the typhoon " Haitang" in Lianyungang,Jiangsu on the morning of July 31,2017 were analyzed,and causes of convection were discussed from the aspects of dynamic,thermal and water vapor conditions. The results showed that the rainstorm process was caused by convection cells with low center of mass,and strong convection mainly occurred in a position where temperature gradient at cloud top was the largest. In North China at 850 hP a,eastern cold air on the south side of anticyclonic circulation moved southwards and joined southeast air flow on the periphery of typhoon,which was the main reason for the occurrence of convection. The circulation of upper-level divergence and lowerlevel convergence was beneficial to the maintaining of convection. The convergence of southeast wind speed on the periphery of typhoon made water vapor accumulate,thereby providing enough water vapor for the appearance of heavy rainfall. K index had good denotative meaning to convection activity,and the process of convection with weak Cape value needs to be paid special attention to in business. The prediction effect of rainfall distribution and areas by the models EC and ECRC was superior to other models.
