检索
E-mail
RSS

作者投稿 主编审稿 专家审稿 远程编辑

热带海洋学报

• • 上一篇    

长江口咸潮入侵格局变化及其成因

裘诚1，朱宜平2，朱建荣3   

  1. 1. 上海市海洋监测预报中心，上海 200062

    2. 上海城投原水有限公司，上海 200125

    3. 河口海岸学国家重点实验室（华东师范大学），上海 200241

  • 收稿日期:2025-07-14 修回日期:2025-07-24 接受日期:2025-07-28
  • 通讯作者: 朱建荣
  • 基金资助:
    上海市科委重点项目（23DZ1203002）；国家自然科学基金项目（U2340225, 42276174）

Changes and causes of saltwater intrusion pattern in the Changjiang Estuary

QIU Cheng1, ZHU Yiping2, ZHU Jianrong3   

  1. 1. Shanghai Marine Monitoring and Forecasting Centre, Shanghai, Shanghai 200062,China

    2. Shanghai Chengtou Raw Water Limited Company, Shanghai,200125, China

    3. State Key Laboratory of Estuarine and Coastal Research (East China Normal University), Shanghai 200241, China

  • Received:2025-07-14 Revised:2025-07-24 Accepted:2025-07-28
  • Contact: Zhu, Jianrong
  • Supported by:

    Science and Technology Commission of Shanghai Municipality (23DZ1203002); National Natural Science Foundation of China (U2340225, 42276174)

PDF (PC)

赞

摘要： 河口咸潮入侵格局变化研究可加深其机制的认识，更好保障河口淡水资源安全利用。本文利用实测地形和盐度资料，分析长江口河势变化和咸潮入侵格局变化，利用数值模式揭示格局变化的成因。2007年至2017年，长江口重大圈围工程导致河道缩窄，显著改变局地地形。在北支下段南侧严重淤积和上端新生沙体的出现，河槽容积分别减小了-33.33%、和-13.26%。在2007年和2025年枯季盐度观测资料表明，北支咸潮入侵和北支盐水倒灌显著减弱，北港咸潮入侵在气候态风下减弱、强北风下加剧。长江口咸潮入侵格局发生了变化。考虑多年月平均径流量和风作用数值模拟结果表明，从2007年至2017年咸潮入侵在北支大幅减弱，在北港上段和中段大部分区域减弱，在南港、北槽和南槽显著加剧。北支盐水倒灌大幅减弱导致南支咸潮入侵减弱，有利于水源地取水。在北支，2月大潮、小潮期间纳潮量减小了2.88、1.98 108m3/s，进入南支的净水通量减小了423、369 m3/s，盐分倒灌的净盐通量减小了10.06、1.10 kg/s。北支上段净单宽盐通量变化也说明北支盐分向南支输运大幅减小。2007年北支盐水倒灌显著，2017年几乎消失。在北港， 2月大潮、小潮期间纳潮量减小了1.92、1.86 108 m3/s，净水通量增加了857、1379 m3/s，分流比增加了12.79%、7.79%，向海的净盐通量减小了2.28、5.42 kg/s。这些因素的变化解释了北港上段和中段大部分区域咸潮入侵减弱的原因。北港分流比的明显增加（相应的南港分流比减小）也说明了南港、北槽和南槽咸潮入侵加剧的成因。北港中段大潮期间小部分区域盐度上升是由横沙小港净盐通量从北槽向北港输运显著增加造成的。本文从净水通量、净盐通量、纳潮量和分流比变化上揭示了长江口咸潮入侵格式变化的动力原因。

关键词: 河势变化, 咸潮入侵, 纳潮量, 分流比, 盐通量

Abstract: Study on the change of saltwater intrusion pattern in estuaries can deepen the understanding of its mechanism and better ensure the safe use of freshwater resources. In this paper, based on the measured topography and salinity data, the changes of river regime and saltwater intrusion pattern in the Changjiang Estuary are analyzed, and the causes of the pattern changes are revealed by using a numerical model. From 2007 to 2017, the major reclamation projects in the Changjiang Estuary led to the narrowing of the river channel and significantly changed the local topography. Due to severe siltation in the south side of the lower reaches of the North Branch and the emergence of new sand body at the upper end, the channel volume decreased by -33.33%, and -13.26%, respectively. The salinity observation data in the dry season of 2007 and 2025 showed that the saltwater intrusion and salt water backflow from the North Branch into the South Branch were significantly weakened, and the saltwater intrusion in the North Channel was weakened under the climate wind and intensified under strong northerly wind. The pattern of saltwater intrusion in the Changjiang Estuary has changed. Considered the multi-year monthly mean river discharge and wind, the numerical simulation results show that from 2007 to 2017, the saltwater intrusion in the North Branch has weakened significantly, weakened in the upper reaches and most areas of middle reaches of the North Channel, and intensified significantly in the South Channel, North Passage and South Passage. The saltwater backflow from the North Branch into the South Branch was greatly weakened, resulting in the weakening of the saltwater intrusion in the South Branch, which is conducive to water intakes in the water sources. In the North Branch, the tidal prism decreased by 2.88 and 1.98 m3/s during spring tide and neap tide in February, the net water flux into the South Branch decreased by 423 and 369 m3/s, and the net salt flux transporting into the South Branch decreased by 10.06 and 1.10 kg/s. The variation of net unit width salt flux in the upper reaches of the North Branch also shows that the salt transport into the South Branch is greatly reduced. In 2007, the saltwater backflow from the North Branch into the North Branch was significant, and it almost disappeared in 2017. In the North Channel, during spring tide and neap tide in February, the tidal prism decreased by 1.92 and 1.86 108 m3/s, the net water flux increased by 857 and 1379 m3/s, the water diversion ratio increased by 12.79% and 7.79%, and the net salt flux to the sea decreased by 2.28 and 5.42 kg/s. The changes of these factors explain the weakening of saltwater intrusion in the upper reaches and most areas of the middle reaches of the North Channel. The obvious increase of the diversion ratio in the North Channel (corresponding to the decrease of the diversion ratio in the South Channel) also explains the causes of the intensification of saltwater intrusion in the South Channel, North channel and South Passage. The rise of salinity in a small part of the North Channel during spring tide is caused by the significant increase of net salt flux from the North Passage into the North Channel. This paper reveals the dynamic causes of the change of saltwater intrusion pattern in the Changjiang Estuary from the changes of net water flux, net salt flux, tidal prism and water diversion ratio.

Key words: river regime change, saltwater intrusion, tidal prism, water diversion ratio, net salt flux