摘要
利用云南124个气象站逐日最低气温和天气现象(霜)资料,计算最低气温低于-5℃的站点数占全省总站数的比例,定义站点比例超出25%的霜冻事件为云南极端霜冻气候事件。分析了云南极端霜冻气候事件的气候特征及环流背景。结果表明,云南极端霜冻事件发生前气温偏低,云量偏多;霜冻发生时夜间晴朗,辐射散热强烈,气温再度下降。这种霜冻属于混合霜冻或称为平流辐射霜冻。极端霜冻气候事件发生的主要原因之一是高空冷平流与底层冷高压控制下夜间晴空辐射冷却降温。发生时空气湿度较发生前小,空气相对干燥。
Using the daily minimum temperature and frost data（1961-2008） at 124 stations of Yunnan Province,the rate of the station numbers of minimum temperature lower than-5 ℃ and the total station numbers of Yunnan are calculated.The extreme frostbite climate events over Yunnan are defined by the rate beyond 25%.At the same time,the climatic characteristics and the circulation features are analyzed.The results indicate that before the extreme frostbite climate events over Yunnan taking place,the temperature is lower and the cloud is more.When the extreme frostbite climate events take place,the clear-sky radiance cooling at night is very strong,the temperature decreases again.This frostbite belongs to mixture frostbite or advection radiance frostbite.The clear-sky radiance cooling at night controlled by the upper level cold advection and lower level cold high is one of main causes for the extreme frostbite climate events over Yunnan.When the extreme frostbite climate events take place,the air humidity is lower than that before.The air is relatively dry.
出处
《灾害学》
CSCD
北大核心
2012年第2期43-48,共6页
Journal of Catastrophology
基金
中国气象局气候变化专项项目(CCSF-09-4)
云南省自然科学基金重点项目(2009CC002)
关键词
极端霜冻气候事件
环流背景
低温
晴空辐射
the extreme frostbite climate events
circulation background
low temperature
clear-sky radiance
