南京地区1次大雾过程中的多普勒雷达回波研究

Study on the Doppler Radar Echo during A Fog process in Nanjing Area

为探讨大雾这种灾害性天气下,新一代多普勒雷达上显示的回波特征以及这种回波的形成机制,以南京地区2007年12月20日1次大雾过程中的多普勒雷达回波为例,利用实际的气象观测资料,对比了折射指数、地面温度、露点温度、水汽压、气压差与回波强度之间的相关性,并探讨了湍流混合作用对回波的影响。结果表明:大雾发生过程中的湍流混合作用引起折射指数的不均匀结构,加之高湿的环境,对多普勒雷达回波有直接影响;通过研究大雾天气下的超折射现象,确定了雾与超折射层之间的关系,对揭示雾与超折射的关系有积极意义。

The paper aimed to study the echo features and formation mechanism of fog which observed by the new generation of Doppler radar, the Doppler radar echo during a fog weather process around Nanjing area on December 20, 2007 was taken as the example. Using the meteorological observation data, the temporal evolution of the reflectivity of fog was analyzed by contrasting the evolution of refractive index-N, surface temperature-t, dew-point temperature-td, vapor pressure-e, surface pressure-p. And the mixing effect of turbulence to the reflectivity was investigated. The results showed that the mixing effect of turbulence caused the non-uniform structure of reflective index, which resulted in the fog echo. Then superrefraction appeared in the fog weather was studied and the relationship of fog and superrefraction layer was found, it is useful to operation application.