一般高潮线与2 m等深线反映黄河三角洲冲淤变化的对比

黄河三角洲是我国乃至世界上陆地动态变化最快的地区之一,其冲淤变化备受关注.利用从遥感影像提取一般高潮线和从实测水深提取2 m等深线反映海岸冲淤的两种方法,对钓口河嘴、清水沟河嘴和清8河嘴分别进行了冲淤面积（淤积、蚀退和净造陆面积）的计算,并对两种方法得到的结果进行了对比.结果显示,两种方法相差较大,钓口河嘴、清水沟河嘴和清8河嘴,2 m等深线反映的冲淤面积（无论是淤积、蚀退还是净造陆面积）绝对值比一般高潮线反映的冲淤面积绝对值都明显偏大.在反映黄河三角洲冲淤变化上,遥感影像提取的一般高潮线可反映陆上三角洲的冲淤变化,实测水深则反映水下三角洲的冲淤变化.

COMPARISON OF MEAN HIGH TIDE LINE AND 2 M ISOBATH REFLECTING EROSION AND ACCRETION OF THE YELLOW RIVER DELTA

The Yellow River delta is one of the areas with the greatest erosion and accretion in China and the world,and its erosion and accretion attract a lot of attention.Two methods for mean high tide lines derived from remote sensing data and 2 m isobaths from field bathymetry data to reflect changes of erosion and accretion were described in detail.Furthermore,remote sensing data acquired on 1 December 1976 and 2 April 1992 and field bathymetry data in 1976 and 1992 covered Diaokou promontory and Qingshuigou promontory,and remote sensing data acquired on 31 May 1996 and 25 June 1999 and bathymetry data in 1996 and 1999 that covered Q_(8) promontory were used in this two methods to reflect area changes of erosion and accretion of Diaokou promontory,Qingshuigou promontory,and Q_(8) promontory,and finally the results from the two methods were compared.The results show that,for Diaokou promontory,Qingshuigou promontory,and Q_(8) promontory,either erosion area,accretion area or net accretion area measured by mean high tide lines are evidently smaller than those by 2 m isobaths.We believe that mean high tide line and 2 m isobath are different indicators in indicating changes of erosion and accretion of the Yellow River delta.But they are complementary: mean high tide lines derived from remote sensing data indicating changes of subaerial delta and field bathymetry data indicating changes of subaqueous delta.