半透明云风矢量高度算法中代表运动像元的使用
半透明云风矢量高度指定是卫星风矢量算法的重要部分,需要使用来自半透明云体的辐射和云下背景辐射两个变量。为了更精确地获得来自半透明云体的辐射,采用像元对追踪相关系数的贡献和红外亮温两个变量进行统计分析,将追踪图像块中的像元分为3个部分：小贡献像元、暖区段大贡献像元和冷区段大贡献像元;对暖区段、冷区段内大贡献像元的特征进行考察表明,冷区段的大贡献像元更能代表追踪图像块运动,称为代表运动像元。选择代表运动像元参与计算来自半透明云体的辐射,对半透明云风矢量高度指定算法进行改进,在该算法中分别使用和不使用代表运动像元,计算FY-2气象卫星风矢量,将结果与欧洲中期天气预报中心（ECMWF）分析场进行对比表...
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| Published in | 应用气象学报 Vol. 28; no. 3; pp. 270 - 282 |
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| Main Author | |
| Format | Journal Article |
| Language | Chinese |
| Published |
国家卫星气象中心,北京,100081
2017
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| Subjects | |
| Online Access | Get full text |
| ISSN | 1001-7313 |
| DOI | 10.11898/1001-7313.20170302 |
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| Summary: | 半透明云风矢量高度指定是卫星风矢量算法的重要部分,需要使用来自半透明云体的辐射和云下背景辐射两个变量。为了更精确地获得来自半透明云体的辐射,采用像元对追踪相关系数的贡献和红外亮温两个变量进行统计分析,将追踪图像块中的像元分为3个部分：小贡献像元、暖区段大贡献像元和冷区段大贡献像元;对暖区段、冷区段内大贡献像元的特征进行考察表明,冷区段的大贡献像元更能代表追踪图像块运动,称为代表运动像元。选择代表运动像元参与计算来自半透明云体的辐射,对半透明云风矢量高度指定算法进行改进,在该算法中分别使用和不使用代表运动像元,计算FY-2气象卫星风矢量,将结果与欧洲中期天气预报中心（ECMWF）分析场进行对比表明,在半透明云高度指定算法中使用代表运动像元,FY-2气象卫星风矢量误差明显降低。 |
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| Bibliography: | 11-2690/P Xu Jianmin （National Satellite Meteorological Center, Beijing 100081 ） wind vector; height assignment; pixels representative of motion Height assignment of semi-transparent clouds needs two variables： Radiation from semitransparent clouds themselves and radiation from the background underneath semitransparent clouds. Generally, the former radiation is calculated using algorithms based on all pixels in tracer boxes. A new algorithm, how- ever, is proposed considering only pixels with great contribution to correlation coefficients during wind vector tracing stage, and only allow these pixels to join the calculation. Scatter diagrams are made with in- frared brightness temperature against their contribution to the feature tracking correlation coefficients. Scatter diagrams show a ＂C＂ shape pattern and can be used to recognize representative pixels of motion. Pixels with relative less contribution to correlation coefficients are at the left side of the ＂C＂ shape with in- frared brightness temperature in th |
| ISSN: | 1001-7313 |
| DOI: | 10.11898/1001-7313.20170302 |