摘要
利用NCEP-GFS(0.5°×0.5°)资料对2020年4月20—22日影响内蒙古东北部暴雪天气过程进行动力因子诊断分析,选取了质量散度、垂直螺旋度、质量垂直螺旋度、水汽垂直螺旋度、散度垂直通量、密度散度垂直通量、水汽散度通量、基于广义位温的热力垂直螺旋度、热力散度垂直通量等动力、热力因子。结果表明:(1)此次暴雪过程是由东北低涡、东北气旋导致的,在降雪初期水汽是从渤海、黄海、日本海输送的,后期以鄂霍次克海的水汽向西输送为主;(2)动力因子对此次暴雪过程的发展和演变有着较好的指示意义;(3)动力因子的大值区基本覆盖强降雪区,在强降雪区域表现为强信号,在非降雪区表现为弱信号,能够描述降雪区动力、热力场的垂直结构特征;(4)分析螺旋度、水汽垂直螺旋度、散度通量、水汽散度通量在降雪天气过程中的特点发现,考虑水汽后,雪区上空对流层中低层的动力学结构被强化,由此可见水汽的作用在于重点突出与降雪区密切相关的对流层中低层动力场结构特征,比起其他的动力因子,水汽垂直螺旋度、水汽散度通量在降雪预报中的指示作用较突出。
A diagnostic analysis was performed for the snowstorm process occurred in northeastern part of Inner Mongolia during April 20222020 based on NCEP-GFS data and the dynamical factors,including mass divergence,vertical helicity,mass vertical helicity,moisture vertical helicity,divergence vertical flux,density divergence vertical flux and moisture divergence flux,the generalized potential temperature based thermal vertical helicity,thermal vertical divergence flux.The results showed that:(1)The snowstorm was caused by Northeast Vortex and Northeast Cyclone.Water vapor was transported from the Bohai Sea,the Yellow Sea and the Sea of Japan in the early stage of snowfall,and from the Sea of Okhotsk mainly in the late stage of snowfall.(2)Dynamical factors had good indication significance for the development and evolution of the snowstorm process.(3)The large value area of dynamic factors could cover the heavy snowfall area basically,showing strong signals in the heavy snowfall area and weak signals in the weak snowfall area,which could describe the vertical structure characteristics of the dynamic and thermal fields in snowfall area.(4)By analyzing the characteristics of vertical helicity,moisture vertical helicity,divergence flux,and moisture divergence flux during snowfall process,it was found that the dynamic structure of the middle-lower troposphere over the snowfall area was strengthened after considering water vapor.So the water vapor could highlight the structural characteristics of the dynamic field in the middle and lower troposphere closely related to the snowfall area.The moisture vertical helicity and moisture divergence flux were better indicators for snowfall forecast than other factors.
作者
德勒格日玛
计燕霞
赵睿峰
Delegerima;Ji Yanxia;Zhao Ruifeng(Inner Mongolia Meteorological Observatory,Inner Mongolia Hohhot 010051)
出处
《内蒙古气象》
2024年第2期3-9,共7页
Meteorology Journal of Inner Mongolia
基金
内蒙古自治区自然科学基金面上基金项目(2021MS04027)。
关键词
内蒙古东北部
暴雪
动力因子
诊断分析
Northeast of Inner Mongolia
Snowstorm
Dynamical factors
Diagnostic Analysis
