摘要
对金塘水道66站次悬沙和流速的周日时间系列进行了互相关分析。单位面积水柱悬沙总量N和流速V的n次方V^n之间的正相关系数在a=0.05置信水平之上的有26站次。其中23站次是在浅水区(水深小于30m)的站位测得的。在这些站次中,n的平均值为2.5,N滞后于V^n的时间大潮时近3h,中潮时为1～2h,小潮时不到1h。从统计意义上看,浅水区N—V^n的相关性相对较好。另一方面,浅水区N—V^n相关性差的站次也达到19站次。 相关程度与N和V^n的非协变成分有关,而非协变成分不仅可由含沙量水平梯度所造成,而且还可由再悬浮过程本身所导致。在深水区,再悬浮作用可引起N和V^n之间较大的非协变。而在浅水区,再悬浮作用造成的非协变成分较少。因此,只有在浅水区才能根据N和V^n的正相关程度判别再悬浮过程在含沙量变化中的相对重要性。金塘水道浅水区不少站次N-V^n相关性较差,按上述分析,这表明非再悬浮因素也是影响是沙浓度的重要因素。
Cross-correlation analysis of 66 diurnal time series of tidal current and SPM data from the Jintang Channel is made in this paper.The maximum positive correlation coefficient between the total mass of SPM in a vertical water column of unit horizontal cross section,N,and the tidal current speed to the power of n,Vn,is above 95% confidence for 26 time series couples,among which 23 are obtained in shallow area with the water depth less than 30m.Under the best positive correlation,the mean value of n oi these 23 couples is 2.5,while the mean time lag differs with tide phase,ranging from about 3 hours during spr tides to less than 1 hour during neap tides,with l^2 hours during intermedium tides.On the other hand,there are 19 time series couples in shallow area and 11 in deep area (H>30m) with low correlation.Therefore,in terms of statistics,the N-Vn correlation is relatively good in shallow area.The extent of correlation is influenced by the non-covariant component of N and Vn series.This non-covariance can be caused not only by the horizontal gradient of SPM concentration,but also by the resuspension process itself.Resuspension leads to larger non-covariance in deep water area but smaller one in shallow one.Thus,only in shallow area can the maximum positive N-Vn correlation tell the relative importance ot resuspension in SPM concentration change with time.The face that some shallow area N-Vn series show low correlation might be due to other factors besides resuspension.
出处
《海洋通报》
CAS
CSCD
北大核心
1989年第4期51-58,6,共9页
Marine Science Bulletin
