基于三波长激光雷达对强卷云后向散射系数波长关系研究

针对高层强卷云(532 nm波长上衰减的后向散射系数比大于20)在全球中出现的概率高达30%,影响地球-大气系统的辐射收支平衡问题. 提出了一种用衰减的后向散射系数颜色比估算后向散射系数颜色比的反演方法,并分析了其误差大小. 基于10个月在合肥西郊上空3波长(1 064,532和355 nm)激光雷达探测到的强卷云数据,得到强卷云的3个后向散射系数颜色比统计分布规律,以及后向散射系数波长指数. 计算结果表明:强卷云的后向散射系数波长指数不再是一个固定不变的常数,而是与波长有关的变量. 

Relationship Between Backscatter Coefficient and Wavelength of Strong Cirrus Cloud Based on a Three-Wavelength Lidar Measurements

The global occurrence of cirrus clouds could reach as high as 30%, which would modulate the balance of radiation budget between the earth and its atmosphere. For strong cirrus cloud (the attenuated backscatter ratio is greater than 20 at 532 nm wavelength), this research proposes an inversion method by using the color ratio of attenuated backscatter coefficient to estimate the color ratio of backscatter coefficient and analyzes its retrieval errors. Based on the measured strong cirrus cloud data over Hefei west suburb using a three-wavelength Lidar (1 064 nm, 532 nm and 355 nm), three statistical backscatter color ratios of strong cirrus cloud were computed, and the backscatter wavelength index of strong cirrus cloud were estimated. The results indicate that the backscatter wavelength index of strong cirrus cloud is no longer a constant as preconception but a variable quantity relative to the wavelength.