大理地区晚霜冻灾害前后大气边界层特征分析  

Case Study of PBL Characteristics before and after Late Frost in Dali

作　　者：徐安伦[1] 杨艳军[1] 孙绩华[2] 刘劲松[1] 李万虎[1] 

机构地区：[1]大理国家气候观象台,大理671003 [2]云南省气象科学研究所,昆明650034

出　　处：《气象科技》2011年第4期513-519,共7页Meteorological Science and Technology

基　　金：云南省气象局科技项目(YB201006);中国气象局行业专项(GYHY201006009)共同资助

摘　　要：研究晚霜冻灾害的成因不仅能提高灾害性天气预测能力,而且可为此类灾害性天气的准确预报以及做好大、小春农作物的防灾减灾工作提供依据。对2009年3月14日云南省大理地区发生晚霜冻灾害期间大气边界层探测资料变化特征的分析结果表明:①此次晚霜冻是在降雨过程后以及前期偏暖的背景下发生的,由高空冷平流和夜间辐射降温形成的混合型霜冻;②晚霜冻发生前,近地层受冷空气影响,各类气象要素呈现出显著的变化特征,白天大气透明度高、无云、风速小、气压高、湿度小,太阳对地表的辐射较强,地表储存的热量较多,气温升高且达到最高值的时间较晚,地面以湍流方式向大气输送的能量以潜热通量为主,傍晚日落后,地表释放的热量开始增多而且远远超过白天吸收的热量,加之水汽放射的长波辐射稳定,获得大气逆辐射补偿的热量相对较少,气温迅速下降,从而近地面空气中的水汽发生凝结现象。By means of the observational data of the planetary boundary layer observation system in the Dali national climate observatory,the late frost event occurred on 14 March 2009 in Dali is analyzed.The main results indicate：（1） The late frost injury occurred after rainfall and warmer weather,resulted from upper-level cold advection and radiation cooling at night.（2） Before the frost,the meteorological elements showed significant changes due to the near surface layer affected by cold air.The main variation features during the day include high atmospheric transparency,cloudless sky,small wind speed,high air pressure,low air humidity,strong solar radiation on the surface,more surface heat storage,and higher temperature and maximum time delay.The latent heat flux played a dominant role in heat transferring.After sunset,the surface heat began to release,and the released heat was more than the absorbed during the day.Water-vapor content and long-wave radiation were stable,and air temperature decreased rapidly,and there appeared condensation phenomenon near the ground.

关 键 词：晚霜冻灾害 大气边界层 气象要素 

分 类 号：P461.4[天文地球—大气科学及气象学]