摘要
利用非静力平衡中尺度模式WRFV3.2、NCEP 1°×1°再分析资料和常规观测资料,对2002年12月12-13日西安地区一次持续大雾天气进行阶段性数值模拟研究。结果表明:利用WRFV3.2模式能较好地模拟出雾的范围、强度和生消过程,但模拟白天雾的强度较弱。这次大雾是平流辐射雾过程,其生成的主要因素是:在夜间辐射降温和弱冷空气入侵的共同作用下,西安地区近地层形成冷气垫,造成低空的逆温层结,逆温的存在为大雾的产生和维持发展提供了有利的层结条件;地面湿度大,逆温层结抑制了水汽向高空传输和能量交换,中低空水汽的输送,为大雾产生提供了充沛的水汽条件;在大雾产生和维持期间的微风,有利于近地面的湍流交换,使辐射冷却作用扩散到适当高度,也使水汽垂直输送到一定高度,有利于雾的产生和发展。而白天太阳辐射导致的地面增温是引起大雾减弱和日变化明显的主要原因。
Based on the NCEP 1°×1° reanalysis data and conventional observation data,a long-lasting fog over Xi＇an area on the December 12-13,2002 is simulated and diagnosed with WRFV3.2 nonhydrostatic model.The result shows that： it simulates successfully in the range,intensity and the evolvement of the fog,but the intensity of the fog in daytime is weaker than what is actually happening.The heavy fog is a typical advection-radiation fog.In the radiative cooling at night and the weak cold air invading together,the cold air cushion produced in Xi＇an,resulting in inversion at lower troposphere layer;the existence of inversion are important to the generation and maintenance of the fog.The humidity of ground is large,and the inversion layer inhibits that water vapor diffused to upper timely,providing abundant water vapor for the fog.The small wind is conductive to the turbulence exchange,the effect of radiation cooling and the water vapor is spread to the appropriate height,which are conductive to the generation and development of the fog.The solar radiation is to result in the obvious daily variation of this fog event.
出处
《气象与环境科学》
2011年第2期31-38,共8页
Meteorological and Environmental Sciences
基金
国家自然基金项目(41005074)资助
关键词
雾
液态水含量
冷气垫
逆温层
fog
liquid water content
cold air cushion
inversion layer
