风云二号静止气象卫星的云相态识别算法

Cloud phase detection algorithm for geostationary satellite data

风云二号静止气象卫星上装载有可见光、中波红外、水汽和红外波段探测通道,其中白天的中波红外通道反射率可以反映云顶粒子的尺度和相态信息.联合使用可见光、中波红外和热红外通道辐射,可构建白天云顶粒子相态识别算法.云相态识别结果与CloudSat卫星的云分类产品相比较,个例分析表明,两种数据对于以深对流和卷云为主的高层冰云识别一致率高于97%,对以层云、层积云和雨层云为主的低层水云的识别一致率为94.98%.将云相态识别算法用于热带气旋云系结构分析,可清晰地揭示热带气旋云系中心对流云区、外围卷云羽区及周边的水云等结构特征.

FengYun-2 geostationary spectral data consists of 5 channels that locate at visible,near infrared,water vapor and far infrared wavelength.Among these channels,the reflectance of near infrared bands at daytime is the function of cloud particle＇s size and thermodynamic phase.The paper proposes a grouped detection method to identify cloud particle＇s thermodynamic phase by reflectance of visible,near infrared bands,and brightness temperature of infrared bands.The identified cloud phase was compared with CloudSat products.The example analysis indicated that two kinds of data regarding consistent rate are higher than 97% for high layer ice cloud,including deep convection and cirrus.For low water clouds,the consistency of two kinds of data got 94.98%.It can clearly show the cloud system structure of tropical cyclone,including central convection cloud area,cirrus around and outside water cloud when using cloud thermodynamic phase identified method analysis the cloud properties of tropical cyclone.