长江口综合整治工程前后潮汐特征分析

Analysis of tidal characteristics before and after construction of regulation projects in Yangtze River estuary

利用改进的Godin潮汐调和分析及预报程序,对长江口北槽附近横沙和北槽中两验潮站的潮位资料进行调和分析,得到不同年份不同时段11个分潮的振幅H、迟角g、平均海平面值Z0以及各站的特征潮位.根据计算结果比较长江口综合整治工程前后横沙站和北槽中站各主要分潮(M2,S2,K1,O1)调和常数的变化,分析综合整治工程前后特征潮位的变化趋势;利用工程前的潮汐调和常数预报2002年、2003年和2006年横沙和北槽中两验潮站的潮位过程,对预报潮位过程和实测潮位过程进行比较.分析结果表明,两站主要分潮的调和常数、特征潮位以及潮位过程,在整治工程后特别是2003年和2006年发生了较明显的变化.

The data of tidal levels at Hengsha station and Middle North Branch station in Yangtze River estuary was calculated and analyzed by use of the modified Godin＇ s tidal harmonic analysis and prediction programs. The harmonic constants H and g of 11 main tidal constituents, the values of mean sea level Z0 and the characteristic tidal levels at different periods were obtained. According to the results, the harmonic constants of four main tidal constituents （M2, S2, K1 and O1 ） at the 2 stations before and after the construction of regulation projects in the deep channel of the north branch of Yangtze River estuary were compared, and the corresponding variation of characteristic tidal level was analyzed. The tidal levels at the 2 stations in 2002, 2003 and 2006 were predicted by means of the harmonic constants before the construction of regulation projects, and the predicted tidal levels were compared with the measured ones. The analytic results show that the harmonic constants of main tidal constituents, the characteristic tidal levels and tidal level processes at the 2 stations after the construction of regulation projects obviously change, especially in 2003 and 2006.