大气科学2025，Vol.49Issue(3)：711-726,16.DOI:10.3878/j.issn.1006-9895.2306.23063
基于雷达观测的福建转折性降雪垂直特征分析
Analysis of Vertical Characteristics of a Transitional Snow Event in Fujian Based on Weather Radars
摘要
Abstract
A transitional snow event occurred in Fujian Province from 19 to 23 February 2022 and was characterized by the coexistence of warm and cold layers in the middle and lower tropospheres,respectively.Multiple precipitation types occurred on the ground,including rain,snow,and wet snow,increasing forecasting difficulty.Based on data from weather radars and other sources,a classification method for precipitation types is first used to identify the periods of snow and wet snow at each weather station;on this basis,the influence of environmental temperature evolution on transitional snow events and the vertical characteristics of transitional snow events are investigated by analyzing the synoptic circulation and vertical features of radar variables.Results demonstrate the following points.(1)The transition between snow and wet snow could be clearly distinguished according to the characteristics of vertical profiles of reflectivity(VPR)and environmental temperature information for areas with uniform topography and surface temperature,i.e.,VPR monotonously increases with decreasing height during a snow stage,while a considerable bright band appears in the middle layer of VPR during a wet snow stage.Great Considerable emphasis should be placed on the capability of weather radars to observe precipitation in the lower level.If radar variables could not capture the change in precipitation characteristics caused by the temperature difference in the near-surface layer due to the limitation of the observation environment,the ground precipitation types could be markedly different although the VPR features resemble each other in higher layers.(2)The vertical characteristics of polarimetric radar variables indicate that the growth mechanism of hydrometeors in the upper layer and above the melting layer is similar to that of general dry snow events.The major differences in transitional snow events are the complicated melting and refreezing processes of particles caused by the warm and cold layers.A bright band signature appears when hydrometeors fall through the warm layer;then,melted particles are fully or partially frozen,reaching the ground as snow or wet snow,depending on the intensity of the cold layer beneath the warm layer and the surface temperature.The vertical features of radar variables(e.g.,the change in the intensity of the bright band)can timely reflect the change in environmental temperature,which is conducive to distinguishing precipitation types and can compensate for the inaccurate forecasting of numerical models and the absence of atmospheric profiles to some extent.关键词
转折性降雪/双偏振雷达/反射率因子垂直廓线/准垂直廓线/垂直特征Key words
Transitional snow event/Polarimetric radar/Vertical profile of reflectivity factor/Quasi-vertical profile/Vertical characteristics分类
天文与地球科学引用本文复制引用
官晓军,戚友存,江颖,苏同华,李婷婷,朱自伟,姜立智,汪澜..基于雷达观测的福建转折性降雪垂直特征分析[J].大气科学,2025,49(3):711-726,16.基金项目
国家重点研发计划项目2022YFC3002904 National Key R&D Program of China(Grant 2022YFC3002904) （Grant 2022YFC3002904）
