GEOGRAPHICAL RESEARCH ›› 2009, Vol. 28 ›› Issue (3): 571-582.doi: 10.11821/yj2009030002

• Earth Surface Processes • Previous Articles     Next Articles

Controlling experiments for dynamic mechanisms of suspended transport of SPM introduced from the Yellow River to the Bohai Sea

LI Guo-sheng1, WANG Hai-long2   

  1. 1. Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China;
    2. Guangdong Electric Power Design Institute, Guangzhou 510663, China
  • Received:2008-11-26 Revised:2009-02-23 Online:2009-05-25 Published:2009-05-25
  • Supported by:

    国家自然科学基金资助项目(40771030;40571020)

Abstract:

Five controlling experiments with a 3D diagnostic model including a wave-current coupled model, the third generation wave model SWAN (Simulating WAves Nearshore) and the bottom boundary layer model driven by the monthly discharge and sediment load of the Yellow River, was conducted to individually explore the effects of tidal currents, wind waves, residual circulation and the Bohai Sea circulation. The simulations on the temporal-spatial variation of SPM (Suspended Particular Matter) concentration and sediment flux from the Yellow River to the Bohai Sea were carried out. It could be discerned that the surface sediment concentration in the waters is quite low except for the Yellow River estuary. The sediment from the Yellow River cannot be delivered in long distance under the condition of tidal currents. Almost all the sediment from the Yellow River is deposited out of the river delta under the condition of the wind-driven residual circulation, and part of the inflow sediment is delivered to and deposited in the Bohai Gulf and the Laizhou Bay. The temporal variation of the suspended load concentration in vertical direction indicates that, the bottom shear stress induced by the wind-driven currents cannot reach the critical shear stress for erosion, and then no re-suspension is incurred. On the basis of wind forcing, the sediment from the Yellow River is mainly transported north-northwestward, and some sediment which is first delivered to the Laizhou Bay is continuously moved northward. On the basis of wind-driven and tide-induced residual circulation, the suspended load transport depicts an obvious 3D structure characteristic, and the depth-integrated sediment flux is quite different from the residual circulation in the Bohai Sea. The residual circulation cannot satisfy the transport structure of the suspended particle matters in the Bohai Sea, especially for the suspended load with complicated vertical processes. The phase of the temporal variation of the sediment concentration and transport pattern due to the interaction between waves and currents is consistent with that of the bottom shear stress, which is modulated by the wind variation, all of which is proved to have a ten-day cycle. Around the Yellow River estuary, currents fields contribute a lot to the outward transportation of the sediment. In other waters, the surface waves-induced bottom shear stress due to the wind forcing makes enormous sediment re-suspended locally, which continues to be transported by horizontal currents.

Key words: sediement from the Yellow River, suspended load transport, dynamic mechanism, controlling experiment