一种面向Cryosat-2数据的多参数联合的lead波形精确识别方法

Identification of Lead by Multi-parameter Method Based on Cryosat-2 Data

远离星下点的lead(浮冰间的开阔水域)对回波波形有重要影响,使计算得到的瞬时海面高存在较大偏差。精确地区分出回波波形中的lead波形,能有效提高瞬时海面高(SSH)的测量精度。目前常用Laxon13算法(PP和SSD)来识别回波中的lead波形,进而计算海冰的出水高度。本文针对Cryosat-2高度计的SARIn模式数据,在Laxon13算法的基础上进行改进,新增了8参数,采用了一种更为精确的lead识别算法,即计算回波能量值在各参数下的统计量,设定分界值(阈值)以识别出lead。该方法采用MAX、PP、PPL、PPR、SSD、LEW、TEW、SLEW、KURT、SKEW共10种参数对lead进行识别,绘制了实验区域基于各个参数的分类图示并识别出lead波形,与Arctic and Antarctic Research Institute(AARI)提供的实际冰况图进行对比分析,确定lead有效识别的5参数。

When Radar altimeter in obtaining high instantaneous sea surface（ SSH）,off-nadir leads has a significant effect on the echo waveform,so that the calculated the sea ice over sea surface（ freeboard） exist serious deviation. Therefore,telling lead from echo waveform accurately,effectively improve the measurement precision of SSH and acquire freeboard measurement with rational precision.Laxon13 algorithm（ PP and SSD） currently used to identify the lead in the echo waveform,and calculating the freeboard. In this paper,we used the Cryosat-2 data in SARIn model in the polar regions,put forward a more accurate method of lead identification. It is using 10 kinds of classification parameters to identify lead,such as MAX,PP,PPL,PPR,SSD,LEW,TEW,SLEW,KURT and SKEW,mapped the experimental area classification and obtained lead content in the experimental area based on various parameters and compared with ice charts published by AARI the images of the actual ice data,through the analysis of the identification of lead deviation was determined with effective identification of five parameters.