摘要
摘要:利用2013～2016年的Aqua MODIS卫星和CloudSat卫星的二级产品资料，对发生在京津冀地区夏季的降水冰云和非降水冰云进行了统计。基于此，对比分析了两类冰云的云类型，研究了二者在云特征参数、云层数及垂直结构上的差异，并且探究了二者在不同通道下云特征参数的相对大小。结果表明：1）京津冀地区的降水冰云以深对流云和雨层云为主，分别占48.63%和34.65%，而非降水冰云以高层云和卷云为主，分别占55.62%和31.58%。2）降水冰云和非降水冰云的平均云顶温度、云顶高度、光学厚度、积分云水总量、有效粒子半径分别为230.99 K、10.90 km、53.26、937.98 g/m²、31.45m和236.17 K、10.10 km、12.81、209.00 g/m²、27.54 μm。3）降水冰云以单层云为主，占80.39%，双层云占18.75%；而非降水冰云仍以单层云为主，占85.35%，双层云则占14.38%，比降水冰云低。4）相较于非降水冰云，降水冰云中卷云和高积云云体位置较高，而高层云和深对流云位置较低。5）随高度变化，降水冰云冰水含量是双峰结构，而非降水冰云是单峰结构；二者的粒子数浓度则差异不大；非降水冰云的粒子有效半径在5～7.5 km随高度变化不大，而降水冰云则随高度减小。6）降水冰云的积分云水总量、光学厚度和粒子有效半径>≥模态[、、分别代表该云特征参数在1.6、2.1、3.7 μm通道中的数值，当n=1, 2, 3时，分别代表光学厚度（b₁）、积分云水总量（b₂）、有效半径这三种（b₃）]的比例都高于非降水冰云，而二者在云参数≥≥模态的比例则有差异。
关键词:CloudSat卫星/
MODIS卫星/
冰云/
降水/
云特征
Abstract: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.
Key words:CloudSat satellite/
MODIS satellite/
Ice cloud/
Precipitation/
Cloud feature



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