1989年以来7个时期黄河三角洲潮沟的形态特征及连通性研究

Morphological Characteristics and Connectivity of Tidal Channels in the Yellow River Delta for 7 Periods since 1989

选择黄河三角洲为研究区,以1989-2016年期间7个时期的遥感数据为数据源,利用ArcGIS软件,采用目视解译方法,提取黄河三角洲潮沟信息;通过计算不同年份潮沟曲率、频数和网络连通性指数等指标,研究20多年来黄河三角洲潮沟发育过程及连通性变化。结果表明,1989-2016年期间,Ⅰ级、Ⅱ级和Ⅲ级潮沟数量依次增加,除2003年的潮沟数量和长度异常增大外,潮沟数量和长度呈波动变化;黄河三角洲潮沟发育的弯曲度整体较小,平均值为1.145,方差为0.000 19,说明潮沟曲度发育较为稳定;黄河口平均每年的潮沟频数为0.811条/km2,在波动增大（不包括2003年）,除1989年和1992年外,黄河三角洲北部的潮沟频数一直小于南部;黄河三角洲北部潮沟发育演化的水文网络连通性特征相对较好,网络结构复杂度较高,而南部潮沟的水文连通性相对较差,网络结构较为简单。

Tidal channels in the Yellow River Delta were extracted by visual interpretation based on 7 images of remote sensing from 1989 to 2016. Some parameters, including tidal channel curvature, frequency, and network connectivity index were introduced so as to decipher development processes and connectivity of tidal channels in 1989, 1992, 1998, 2003, 2009, 2012, and 2016. The results indicated that numbers of first, second,third grade tidal channels were increasing from 1989 to 2016 in turn. Except for the abnormal in 2003, the numbers of tidal channels and lengths fluctuated within a limited range for other 6 periods. The bending degree of tidal channels in the Yellow River Delta was small with an average of 1.145 and a variance of 0.000 19. It implied that tidal channel curvature was relatively stable in the Yellow River Delta. The average frequency of tidal channels in the Yellow River Delta was 0.811 tidal channels per square kilometer, and increasing from 1989 to 2016（excluding that in 2003）. In 5 years but 1989 and 1992, tidal channel frequencies in the north bank of the Yellow River were lower than those in the south bank. The hydrological connectivity of tidal channels in the north bank of the Yellow River showed more complex network structure than that in the south bank.