瓯江河口潮汐特征变化及其原因分析

利用瓯江河口沿程4个长期潮位站的监测数据,结合潮流数学模型,计算分析1960~2014年各站年均高、低潮位,年均涨落潮历时特征值,得出瓯江河口近54 a来潮汐特征变化过程,分析相关影响因素,探讨河口潮汐特征变化原因。结果表明:瓯江河口下游的龙湾站多年来潮汐特征尚无明显趋势性变化;河口中上游的温州、梅岙和花岩头站趋势性变化明显且变化规律基本一致,整体表现为高潮位上升、低潮位下降、潮差增大,涨潮历时延长、落潮历时缩短的特征,时空格局上,上游站位潮汐特征变幅大于下游站位,低潮位变幅大于高潮位变幅。原因分析表明,流域来水对河口潮汐特征的影响不明显;堤线调整和围垦工程等人类活动主要引起工程局部河段潮位变化;河口高强度的采砂活动应是温州、梅岙、花岩头站潮汐特征变化的主因。瓯江河口不同河段因受径流、潮流、人类活动等因素的影响程度不同,其潮位特征沿程的变化特点也不同,需要在河口工程设计、防洪减灾与河口治理等方面予以关注。

CHANGE OF TIDAL CHARACTERISTICS IN THE OU-JIANG ESTUARY

This study analyzes the past 55 years (1960-2014) decadal tidal characteristics of the four tidal stations of the Ou-jiang estuary,and explores the affecting factors and the possible reasons that caused those variations.The results show the tidal characteristics of Longwan tidal station had no obvious changes in the period.Wenzhou,Meiao and Huayantou station were presented similar tidal characteristics,which includes the rising high tide levels,declining low tide levels,increasing tidal ranges,extending flood time and shorting ebb time.It seems the basin runoff changes didn't effect on those estuarine tidal characteristics.The main reasons that caused regional tide variations were human activities such as embankment constructing and cultivation in former water areas.The tidal changes at Wenzhou,Meiao and Huayantou station were most due to the intensive river sand exploitations.So the Ou-jiang estuary project design and water managements should be considered sections separately.