如东海域挟沙力公式及相关系数分析

Analysis of sediment carrying capacity formulae and correlation coefficients applied in Rudong sea area

利用如东海域14个测点冬季与夏季水文泥沙资料,采用最小二乘法,对常用的挟沙力公式进行大潮、中潮、小潮及落潮、涨潮多种方式拟合,得到了多个挟沙力表达式,各挟沙力公式对应相关系数大小有异。以往我们选择挟沙力公式时,倾向于选择相关系数最大的公式,认为相关系数越大,拟合出来的公式越好。但是根据统计分析的知识,相关系数不能独立用来作为拟合优劣的判据,而应结合置信度及临界相关系数来选择。本文通过对拟合出的各公式相关系数及临界相关系数进行分析,并利用相对误差进行检验后认为,由如东海域拟合出的多个挟沙力公式,在满足大于临界相关系数的基础上均是可以采用的。

With hydrologic and sediment data at 14 measuring points in Rudong sea area in winter and in summer,several formulae of sediment carrying capacity are obtained by using the least square method.These formulae are respectively obtained from data of spring,mean,neap tide and flood,ebb tide.Their correlation coefficients are different.Usually,the formula with biggest correlation is preferred,as the bigger the correlation coefficient is,the more precise the formula is.But according to the knowledge of statistics,the satisfaction of the linear regression cannot be judged solely with the standard of correlation coefficient,instead,the confidence level and critical correlation coefficient should also be considered.After analyzing the correlation coefficient of each formula,comparing then with the critical number and using the relative error to test the satisfaction,the formulae obtained from the Rudong sea area are considered to be applicable,as long as their correlation coefficients are larger than the critical number.