THE ALGORITHM AND VERIFICATION OF GROUND CLUTTER IDENTIFICATION BASED ON FUZZY LOGIC
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摘要: 提出一种基于模糊逻辑的新一代天气雷达地物回波识别方法。通过统计典型个例的回波特性得到隶属度函数及权重,并根据反射率因子范围的不同设置相应的隶属度函数及权重。该方法针对降水强度量级的回波,即反射率因子不小于15 dBz,对于非降水强度回波则不进行处理,从而保留对短临预报具有指示作用、且强度较弱的特征回波,如晴空湍流回波以及阵风锋回波。根据雷达回波垂直方向连续性对剔除地物回波所产生的“空洞”进行填补,从而进一步减小地物回波对雷达数据质量造成的影响。最后通过两种方法对识别算法进行效果检验,结果表明该算法对地物回波有显著的识别效果。Abstract: This paper proposes a method for ground clutter identification based on the fuzzy logic technique in CINRAD. Derived from the characteristics of radar echoes in typical cases, membership functions and their weights vary with radar reflectivity. This method deals with the echo at precipitation intensity of no less than 15 dBz but leaves the echo at nonprecipitation intensity untreated, thus keeping weak characteristic echoes useful for nowcasting of such features as clear air turbulence and gust fronts. To weaken the influence from the ground clutter further, gaps created by removing ground clutter will be filled based on the continuity of echoes in the vertical direction. This algorithm of identification has been tested in two ways and the result shows that it performs well in ground clutter identification.
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Key words:
- weather radar /
- ground clutter identification /
- fuzzy logic /
- echoes characteristics /
- quality control
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图 3 同图 2,但为TDBZ(单位:dB)
图 4 同图 2,但为Vabs(单位:m/s)
图 7 同图 6,但为混合型降水
图 8 同图 6,但为孤立单体
图 9 同图 6,但为飑线
图 11 同图 10,但为Z=25~35 dBz
图 12 同图 10,但为Z≥35 dBz
表 1 广州新一代天气雷达主要性能参数[12]
物理量 性能参数 工作频率/MHz 2 885 发射机峰值功率/kW 650~800 脉冲重复频率/Hz 318~1 304 波束宽度/° 0.99 天线直径/m 8.54 天线增益/dB 45 动态范围/dB 93 极化方向 水平 -
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