基于风廓线雷达的晴空对流层动力湍流特征研究

Research on the Characteristic of Clear-Day Dynamic turbulence in Troposphere Based on Wind Profile Radar

风廓线雷达作为一种新型遥感设备，其回波信号包含丰富的湍流信息。提出了一种利用风廓线雷达回波信号反演动力湍流的方法，分析了对流层速度结构常数Cv^2的变化特征，并根据近地面速度湍流模型研究了对流层湍流速度脉动的特性。结果表明：1）动力湍流强度随高度增加逐渐减弱，夜间减弱速度大于白天，且在边界层顶处Cv^2具有较明显的日变化特征；2）Cv^2与速度起伏方差σ^2的对数值具有较好的线性关系，线性拟合度达0．896；3）对流层湍流的速度脉动较弱，σ^2量级在10^-3～10^-2m^2·s^-2之间。

Wind profile radar is a new kind of instruments in remote sensing sounding, the echo signals of which contain abundant informations of turbulence. An algorithm for retrieval dynamic turbulence is proposed using the echo of wind profile radar, and the characteristic of velocity structure constant Cv^2 in troposphere is analyzed. Also, the turbulent velocity fluctuation in troposphere is discussed based on the velocity turbulence model. The results show that.. 1） the strength of dynamic turbulence decreases along with the increase of the height, the lapse rate of which in the night is more rapid, and the Cv^2 has remarkable diurnal variability at the top of boundary layer; 2） there is good linear relation betweenCv^2 and the natural logarithm of velocity fluctuation variance a2 , and the closeness of linear fitting could reach 0. 896; 3） the velocity fluctuation of turbulence in troposphere is relatively small, and ae distributes between 10 3 m2 . s-2 and 10 2 m2·~ s-2 in clear-air.