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
利用地面气象观测站资料、加密地面观测资料和欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts, ECMWF)第五代大气再分析数据(ECMWF Reanalysis v5,ERA5;分辨率为0.25°×0.25°)逐小时资料,对山...利用地面气象观测站资料、加密地面观测资料和欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts, ECMWF)第五代大气再分析数据(ECMWF Reanalysis v5,ERA5;分辨率为0.25°×0.25°)逐小时资料,对山东2021年11月6—8日极端暴雪过程雪水比影响因子进行研究。结果显示:此次暴雪过程平均雪水比分布总体呈“北大南小、西大东小”的分布特征,降雪初期产生的雪水比小,降雪中后期产生的雪水比大;温度偏高、云内液态水含量较高的地区雪水比较小,温度偏低、云内液态水含量较低的地区雪水比较大;雪水比与地面气温、地表温度呈负相关,地面气温与雪水比的相关性最大,积雪产生之后地表温度与雪水比变化无明显相关。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
本文采用ECMWF(European Centre for Medium-Range Weather Forecasts)细网格和NCEP(National Centers for Environmental Prediction)模式数据、NCEP 1°×1°再分析资料、降雪加密观测和常规资料,对2022年初的5次降雪过...本文采用ECMWF(European Centre for Medium-Range Weather Forecasts)细网格和NCEP(National Centers for Environmental Prediction)模式数据、NCEP 1°×1°再分析资料、降雪加密观测和常规资料,对2022年初的5次降雪过程进行对比分析,发现5次降雪过程均为雨转雪过程,且持续时间相对较短,平原为雨夹雪或小雪到中雪,山区中到大雪,局部暴雪,数值模式预报的积雪深度与实况相差甚远;大尺度环流形势为500 hPa中低纬南支槽或弱波动配合700 hPa上的暖湿气流和中低层冷空气,造成边界层浅薄的冷垫上温度骤降而在短时间内形成降雪;相较于平原地区,高山区上空温度层结与最大上升运动中心的配置,有利于降雪粒子较长时间维持在有利于枝状雪花的形成区域,且高山区云底云水含量显著偏低、整层温度足够低,故高山区更利于暴雪的形成。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.
文摘利用地面气象观测站资料、加密地面观测资料和欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts, ECMWF)第五代大气再分析数据(ECMWF Reanalysis v5,ERA5;分辨率为0.25°×0.25°)逐小时资料,对山东2021年11月6—8日极端暴雪过程雪水比影响因子进行研究。结果显示:此次暴雪过程平均雪水比分布总体呈“北大南小、西大东小”的分布特征,降雪初期产生的雪水比小,降雪中后期产生的雪水比大;温度偏高、云内液态水含量较高的地区雪水比较小,温度偏低、云内液态水含量较低的地区雪水比较大;雪水比与地面气温、地表温度呈负相关,地面气温与雪水比的相关性最大,积雪产生之后地表温度与雪水比变化无明显相关。
文摘本文采用ECMWF(European Centre for Medium-Range Weather Forecasts)细网格和NCEP(National Centers for Environmental Prediction)模式数据、NCEP 1°×1°再分析资料、降雪加密观测和常规资料,对2022年初的5次降雪过程进行对比分析,发现5次降雪过程均为雨转雪过程,且持续时间相对较短,平原为雨夹雪或小雪到中雪,山区中到大雪,局部暴雪,数值模式预报的积雪深度与实况相差甚远;大尺度环流形势为500 hPa中低纬南支槽或弱波动配合700 hPa上的暖湿气流和中低层冷空气,造成边界层浅薄的冷垫上温度骤降而在短时间内形成降雪;相较于平原地区,高山区上空温度层结与最大上升运动中心的配置,有利于降雪粒子较长时间维持在有利于枝状雪花的形成区域,且高山区云底云水含量显著偏低、整层温度足够低,故高山区更利于暴雪的形成。
