Comparative Analysis of the Features of Precipitating and NonprecipitatingIce Clouds in the Beijing-Tianjin-Hebei Region in Summer

On the basis of the Level 2 product data of Aqua MODIS satellite and CloudSat satellite from 2013 to 2016, precipitating and nonprecipitating ice clouds that occurred in the Beijing-Tianjin-Hebei region in summer were counted. Moreover, the cloud feature parameters, cloud layer numbers, and cloud phase of the two types of ice clouds are compared and analyzed. The differences between the two in the vertical structure are investigated and the relative sizes of the cloud parameters in different channels are examined. Results show that precipitating ice clouds are dominated by deep convective and nimbostratus clouds, accounting for 48.63% and 34.65%, respectively. The mean cloud top temperature, cloud top height, cloud optical thickness, cloud water path, and effective particle radius are 230.99 K, 10.90 km, 53.26, 937.98 g/m², and 31.45 μm, respectively. Meanwhile, nonprecipitating ice clouds are dominated by altocumulus and cirrus clouds, accounting for 55.62% and 31.58%, respectively. The mean cloud top temperature, cloud top height, cloud optical thickness, cloud water path, and effective particle radius are 236.17 K, 10.10 km, 12.81, 209.00 g/m², and 27.54 μm, respectively. Precipitating ice clouds mainly consist of single-layer clouds (80.39%). However, double-layer clouds still account for a large proportion (18.75%) and are higher than nonprecipitating ice clouds. Moreover, nonprecipitating ice clouds still consist of single-layer clouds (85.35%) and double-layer clouds (14.38%). Compared with nonprecipitating ice clouds, the position of cirrus and altocumulus clouds, which are higher than 1-9 and 0-1.5 km, respectively, in precipitating ice clouds is higher, whereas the position of altostratus and deep convective clouds, which are lower than 0-0.5 and 0.5-3 km, respectively, are lower. The ice water content of nonprecipitating ice clouds varies with height as a double-peak structure, whereas that of precipitating ice clouds is a single-peak structure. The particle number concentrations of precipitating and nonprecipitating ice clouds vary slightly with height. The particle effective radius of nonprecipitating ice clouds varies slightly with height from 5 to 7.5 km, whereas that of precipitating ice clouds decrease with height. The ratio of the cloud water path, optical thickness, and particle effective radius of precipitating ice clouds >≥ mode where , , and represent the values of the cloud parameters at 1.6, 2.1, and 3.7 μm, respectively; when n=1, 2, 3, they represent the optical thickness (b₁), total amount of integrated cloud water (b₂), and effective radius (b₃) is higher than that of nonprecipitating ice clouds. Moreover, the ratio of the cloud parameters in the ≥ ≥ mode is different.