现有波群因子的统计研究

Statistical study on existing grouping factors in ocean waves

自Ｇｏｄａ于１９７０年提出谱峰度参量Ｑｐ以来，迄今表征波群强度的因子己有十多种。对文中提及的较常用的１１种因子即以后被称为现有波群因子，各作者都强调自己的优点，但何者为较好，直至目前尚无客观的评价。依据从三个测点获得的１１１组数据对现有波群因子予以检验，若某一因子在较短的记录长度内有连续三个值且其中最大值和最小值满足：（最大值减最小值）不大干０．００５，则被称为稳定的波群因子；若这种因子又满足三个条件，即它在任一序数中出现的次数最多、在整条记录中出现的总次数最多和在整条记录的最初１２８０ｓ内出现率最大，则被称为较佳波群因子。就检验的个例而言，（波高的）平均连长（Ｌ１）和波高与周期的相关系数［ＲＨＴ（０）］就是这种因子。将这两个因子连结起来，今后称之为联合波群因子．因此，建议以此联合波群因子表征波群强度将会较前人采用的单因子的为好．

There have been more than 10 factors to be used to characterize the intensity of wave groups since the spectral peakness parameter, Qp, was proposed by Yoshimi Goda in 1970. As to 11 factors more cur- rently employed, i. e., hereafter called existing grouping factors, mentioned in the paper. each of the authors puts emphasis on the advantage of his own. Which of the existing grouping factors is better?Nobody made an objective appraisement as yet. New a trial examination of the existing grouping factors has been made on the basis of 111 data sets obtained from three observation point. in the paper. If one of the existing grouping fac- tors which has the maximum and minimum value among three values in succession within a shorter record satisfying that maximum value minus-minimun value is not greater than 0. 005 . then it is called the steady grouping factor. If this factor satisfies the other three conditions : the most frequency in an arbitrary ordinal number , the most total frequency in the whole record . and the largest occurrence probability within initial 1 280 s of the whole record, then it is called better grouping factor. So far as the cases are examined, to this factor belong the mean length of runs [of wave heights (L1) ] and correlation coefficient between wave heights and periods [RHT( 0 ) ]; the two factors are connected which are hereafter called a united grouping factor. Therefore, we suggest that the united grouping factor characterized the intensity of wave groups shows better than single one adopted by forerunners.