\r叶涛焱¹，李 莉^{1, 2}，王咏雪³，袁金雄⁴，贺治国^{1, 2}，夏乐章\r^{1, 2}\r
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AuthorsHTML:\r叶涛焱¹，李 莉^{1, 2}，王咏雪³，袁金雄⁴，贺治国^{1, 2}，夏乐章\r^{1, 2}\r
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AuthorsListE:\rYe Taoyan¹，Li Li^{1, 2}，Wang Yongxue³，Yuan Jinxiong⁴，He Zhiguo^{1, 2}，Xia Yuezhang\r^{1, 2}\r
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AuthorsHTMLE:\rYe Taoyan¹，Li Li^{1, 2}，Wang Yongxue³，Yuan Jinxiong⁴，He Zhiguo^{1, 2}，Xia Yuezhang\r^{1, 2}\r
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Unit:\r\r1. 浙江大学海洋学院，舟山316021；\r
\r\r2. 卫星海洋环境动力学国家重点实验室(国家海洋局第二海洋研究所)，\r杭州 310058；\r
\r\r3. 浙江大学工业技术转化研究院，杭州 310058；\r
\r\r4. 台州市海洋与渔业局，台州 318000\r
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Unit_EngLish:\r1. Ocean College，Zhejiang University，Zhoushan 316021，China；
2. State Key Lab of Satellite Ocean Environment Dynamics(Second Institute of Oceanography，SOA)，Hangzhou 310058，China；
3. Industrial Technology Research Institute of Zhejiang University，Hangzhou 310058，China；
4. Oceanic and Fishery Department of Taizhou，Taizhou 318000，China\r
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Abstract_Chinese:\r1974 至2020 年间，杭州湾沿岸潮滩累计减少面积将达1 290 km2，占杭州湾水域面积的25.8%．基于FVCOM 水动力数值模型，耦合水沙密度，引入悬浮泥沙对底边界层的影响，并考虑细颗粒泥沙絮凝过程，建立河口三维细颗粒泥沙数值模型，提高了高悬沙浓度河口悬沙数值模拟的准确性．实测及卫星反演数据验证结果显示，该模型能较好地模拟杭州湾水沙运动．基于所建模型，采用不同时期的杭州湾潮滩数据，研究潮滩面积减小对悬沙浓度、悬沙通量及冲淤分布的影响机理．结果显示：潮滩减少过程中湾内流速及底床切应力发生变化，进而影响湾内悬沙浓度．杭州湾潮滩减少导致乍浦以西水域流速降低，月均悬沙浓度最大减幅高达30%．乍浦以东水域流速增大，月均悬沙浓度升高约15%．潮滩减少主要通过影响潮泵效应，进而改变湾内悬沙输运特征，平流输沙项在潮滩减少过程中对杭州湾悬沙特征的影响较小．1974 至2003 年间，杭州湾潮滩面积减少约787 km2，澉浦断面潮泵效应增强，陆向悬沙净通量增大，金山、芦潮港断面陆向悬沙净通量减小，杭州湾淤积量减少．2003 至2020 年间潮滩面积减少约503 km2，金山、芦潮港断面潮泵效应增强，陆向悬沙净通量增加，而澉浦断面由于潮泵效应减弱导致悬沙净通量减小．杭州湾内湾淤积量不断增大，外湾冲刷量逐渐增大．研究结果可为河口海岸规划和环境管理提供科学依据．\r
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Abstract_English:\rThe area of the tidal flat in Hangzhou Bay(HZB)was reduced by 1 290 km2 between 1974 and 2020，which covered 25.8% of the total area of HZB. For the present study，a model of the fine sediments of Hangzhou Bay was coupled with the finite volume coastal ocean model(FVCOM)to study the multi-decadal changes in the suspended sediment dynamics and erosion/deposition pattern in the bay due to tidal flat reduction. The model considered the coupling of suspended sediment concentrations(SSC)with water density，and also accounted for the effects of a sediment-induced bottom boundary layer and flocculation processes. The modeled tidal level，currents and SSC agreed well with observations and remote sensing data. According to model results，from 1974 to 2020，the monthly-averaged SSC decreased by 30% at a location upstream of Zhapu due to the reduced current and bed shear stress. Conversely，the monthly-averaged SSC increased by 15% at a location downstream of Zhapu due to increased current and bed shear stress. Our findings indicate that the tidal pumping effect plays a major role in changing the net sediment transport，while sediment advection has a minor influence，when the tidal flat is reduced. The area of the tidal flat was reduced by 787 km2 from 1974 to 2003. The reduction in the tidal flat amplified the net sediment flux at the Ganpu cross-section，while dampening that at the Jinshan and Luchaogang cross-sections，by changing the tidal pumping effect. The sediment deposition subsequently decreased in the bay. The reduction in the tidal flat area was model-predicted to be about 503 km2 from 2003 to 2020. The net sediment flux showed the opposite change，compared with that of 1974 to 2003. Sediment deposition/erosion increased in the inner/outer bay. Our results will contribute to the planning and rational utilization of tidal flats in similar estuaries.\r
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Keyword_Chinese:悬沙模型；净输沙；潮滩减少；杭州湾\r

Keywords_English:suspended sediment model；net sediment transport；tidal flat reduction；Hangzhou Bay\r


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