内蒙古东南部大到暴雪过程影响系统及物理量场特征分析  

Statistical Analysis of Physical Quantity Fields for a Heavy Snowstorm in Southeastern Inner Mongolia

作　　者：徐建国[1] 赵立清[1] 姜凤友 纪圆明 宋玉红[1] Xu Jianguo;Zhao Liqing;Jiang Fengyou;Ji Yuanming;Song Yuhong(Tongliao Meteorological Service,Inner Mongolia,Tongliao 028000;Hulunbeier Meteorological Service,Inner Mongolia,Hailaer 021008)

机构地区：[1]内蒙古通辽市气象局,通辽028000 [2]内蒙古呼伦贝尔市气象局,海拉尔021008

出　　处：《气象科技》2018年第5期919-931,共13页Meteorological Science and Technology

基　　金：内蒙古自治区气象局科技创新项目"通辽赤峰大到暴雪天气分析及预报方法研究"(nmqxkjcx201404)资助

摘　　要：利用1951—2013年63a的地面观测、MICAPS、NCEP、历史天气图等资料,将发生在内蒙古东南部的150次大到暴雪过程的700hPa影响系统分为7种类型,对其中2007—2013年的26次大到暴雪过程,分型统计了25个测站中的降大到暴雪的测站的物理量场。结果表明:散度场总体表现为低空辐合、高空辐散的特征,对应了高、低空急流的耦合作用,使得垂直速度场维持整层、长时间的强上升气流,因类型不同达到的高度有所不同;最大相对湿度分布在925~500hPa之间,水汽通量散度辐合主要表现在925~700hPa,比湿场随高度增高迅速减小,各类型925hPa最小比湿在2~2.9g·kg^(-1)、850hPa最小比湿在1.7~3.2g·kg^(-1)之间,反映了低空西南暖湿急流的作用,尤其是925hPa超低空急流对大到暴雪的贡献;75百分位的1000hPa即近地面层基本为冷平流,925hPa以上均为暖平流,具有冷垫作用,为大到暴雪的发生提供了动力触发条件。Using the surface observation,MICAPS and NCEP data from 1951 to 2013,the 700 hPa influence systems of 150 heavy snowstorms occurred in the southeastern Inner Mongolia are divided into seven types,and for the 26 heavy snowstorms from 2007 to 2013,the physical quantity fields are classified and analyzed for 25 stations.The results show：Overall,the divergence field had the characteristics of the low-level convergence and high-level divergence,which corresponded to the coupling effect of high and low jet streams.The vertical velocity field and a long time strong updraft in the whole layer maintained.Depending on the height of the weather patterns,the maximum relative humidity was between 925 and 500 hPa,and the water vapor flux divergence/convergence was mainly between 925 and 700 hPa.With high elevation,the specific humidity rapidly decreased.The minimum humidity for various weather patterns at925 hPa was 2 to 2.9 g·kg（-1）,and that at 850 hPa was 1.7 to 3.2 g·kg（-1）,reflecting the effect of the lowlevel southwest warm water jet,especially the contribution of the 925 hPa super-low jet stream.At the1000 hPa（the 75 th percentile）near the ground layer there was basically cold advection.Above 925 hPa there was all warm advection,which had obvious ＂cold cushion＂ effect and provided the trigger conditions for the heavy snowstorm.

关 键 词：大到暴雪 分型 物理量场 特征分析 

分 类 号：P456.8[天文地球—大气科学及气象学]