以Jason-2卫星雷达测高数据监测洪泽湖水位为例,分析了湖泊水位沿卫星轨迹呈"V"字形分布的原因.分析发现:由于湖泊面积相对较小,受陆地影响,测高波形中陆地反射信号占主导地位,水面反射产生的上升前缘非常小,导致波形跟踪出错.解释了波形形成的机制、造成水位计算错误的原因,结合遥感影像证明了解释的正确性,并给出了相应的波形重定算法.结果表明,该重定算法优于常用的波形重定算法,剔除异常值后水位标准差为0.09m,为湖泊区域的测高数据处理提供了一种参考.%The phenomenon that the distribution of water level along the satellite track is like a "V" is analyzed.To show the problem,the water level of Hongze Lake is calculated by Jason-2 satellite altimeter data.The analysis shows that the signal of ground reflection dominates the shape of waveform due to the small size of the lake and influence of land.In this case,the leading edge produced by water is not obvious, so it is easy to retrack the wrong middle point.The mechanism of waveform formation and the causes of water level calculation errors is explained and proved with remote sensing images.And the corresponding waveform retracking algorithm is proposed.The results indicate that the proposed algorithm performs better than common waveform retracking algorithm.After removing the abnormal value,the standard deviation of the water level reaches 0.09m,which means the analysis method could be a reference for altimeter data processing in lake region.
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