摘要
应用1976～2005年云南126个气象站观测资料及2001～2005年的高空探测资料,统计分析了云南辐射雾的时空分布气候特征、形成雾的天气环流背景及要素成因。结果发现：云南雾日数逐年呈现波状变化,总体趋势上呈下降趋势,但雾的日变化规律较为稳定;形成雾的天气形势有偏西气流型和偏北气流型,其中偏北气流型成雾重、持续时间长。成雾物理机制分析表明,近地层良好的水汽条件、静风或弱的风力条件、晴空少云、地面变性冷高压后部的均压场环境、低层大气弱的上升运动、中高层大气较强的下沉运动、低层暖平流、中高层冷平流以及边界层存在逆温层等特征是形成雾的重要条件。
A statistical analysis is made of the spatial-temporal distribution, weather circulation background and formation causes of radiation fogs in Yunnan Province by means of the radiosonde data in recent five years and the conventional meteorological data from 1976 to 2005 of 126 weather stations over Yunnan. The results show that the number of foggy days exhibited a year-by-year undulatory variation trend and an overall dropping tendency, but the diurnal variation of fogs is relatively stable; the synoptic patterns favorable to fog formation include the westerly flow and the northerly flow patterns, with the northerly pattern accompanying heavier and longer-duration fog process. The analysis of formation mechanisms of fogs indicates that the formation conditions for fogs include such weather situations as the good water vapor condition around the surface layer, calm or weak wind, clear sky or slight cloudiness, uniform pressure field behind the ground transformed cold anti-cyclone, weak ascending movement and warm advection at the lower levels, strong descending movement and cold advection at middle and upper levels, and an inversion layer in the boundary layer.
出处
《气象科技》
2008年第3期281-288,共8页
Meteorological Science and Technology
基金
中国气象局基础研究项目"云南雾的监测及预报预警"和"云南省气象局开放实验室"共同资助
关键词
辐射雾
气候特征
环流背景
成因
radiation fog, climatic characteristic, circulation background, formation cause
