中国主要入海河口咸潮入侵变化特征

Salt tide intrusion characteristics in main estuaries of China

长江口、钱塘江口和珠江口是受咸潮影响较为严重的区域。本文利用全国沿海海平面变化影响调查、沿海水文观测等数据,分析了近十年长江口、珠江口和钱塘江口咸潮入侵的变化特征及影响。分析结果表明:(1)2009原2018年,长江口咸潮入侵次数和持续时间均呈减少趋势,该时段长江口共监测到约48次咸潮入侵过程,发生时间集中在9-10月至翌年5月,其中3月和11月入侵次数较多,分别为12次和7次。(2)钱塘江口咸潮入侵过程受沿海季节性海平面影响显著,12月至翌年3月为钱塘江口季节性低海平面期,4-7月上旬径流量较大,上述两个时期钱塘江口受咸潮入侵的影响均较小,7月下旬至11月上旬,钱塘江口处于季节性高海平面期,是咸潮影响的集中时段。(3)2009原2018年,珠江口共监测到约57次咸潮入侵过程,发生时间集中在9-10月至翌年3-4月,其中1月、2月和10月咸潮入侵次数较多,均超过10次,2015年至今咸潮持续时间明显增加。(4)咸潮入侵次数和持续时间与基础海面和径流量等密切相关,咸潮入侵影响三大河口沿线水厂供水以及工农业生产取水,给沿岸城市的居民生活、工农业生产和渔业养殖等造成一定不利影响。

The Yangtze River Estuary,the Pearl River Estuary and the Qiantang River Estuary are much influenced by salt tide intrusion.Based on sea level change impact investigation,tide gauge and runoff observation data,the characteristics of salt tide intrusion at above river estuaries in the past decade are analyzed.Results show that:(1)At the Yangtze River Estuary,48 salt tide intrusions occurred during 2009-2018,which generally occurred from September/October to May of the following year,and appeared more in March and November,for 12 and 7 times respectively.In recent years,the occurrence and duration of salt tide intrusion at the Yangze River Estuary are all decreasing in general.(2)The salt tide intrusion at the Qiantang River Estuary is influenced significantly by seasonal sea level.The seasonal sea level is low during December to March of the following year,and the runoff is high during April to early July.Salt tide intrusion impacts were thus relatively small during these two periods.For the time of late July to early November,sea level reaches its seasonal high and the runoff is small,resulting in concentrated salt tide impact.(3)At the Pearl River estuary,about 57 salt tide intrusions occurred from 2009 to 2018,which generally appeared from September/October to March/April of the following year,and appeared more in January,February and October.(4)The duration of salt tide impacts are mainly related to runoff and sea level.Salt tide intrusion affects the water intake of waterworks,and has certain detrimental impacts on industrial and agricultural production and daily life of local people.