Dynamic Response of the Fluid Mud to a Tropical Storm

Dynamic Response of the Fluid Mud to a Tropical Storm

Ge, Jianzhong (Shanghai Estuarine and Coastal Science Research Center; Institute of Eco-Chongming (IEC))
Chen, Changsheng (University of Massachusetts Lowell)
Wang, Zhengbing (TU Delft Coastal Engineering; Deltares)
Ke, Keteng (Shanghai Investigation Design and Research Institute Co.; Shanghai Estuarine and Coastal Science Research Center)
Yi, Jinxu (Shanghai Investigation Design and Research Institute Co.)
Ding, Ping Xing (Shanghai Investigation Design and Research Institute Co.)

2020

Fluid mud (FM) is a unique sedimentary feature in high-turbidity estuaries, where it can make a rapid contribution to morphodynamics. Insufficient field measurements and fixed-point monitoring lead to deficient understandings of the formation, transport, and breakdown of the FM under extreme weather conditions. A field survey was conducted in the Changjiang Estuary during the period of turbidity maximum, just after Typhoon Haikui. The measurements captured the formation of the FM beneath the suspended layers, particularly around the lower reach of the North Passage. The thickness of the observed FM gradually decreased landward along the channel, with the maximum value reaching ~0.9 m. The major features of the observed storm-induced FM were simulated using the Finite-Volume Community Ocean Model. The results indicated that the initial appearance of the FM was the result of a typhoon-intensified, salinity-induced stratification in the outlet region. The subsequent landward propagation of the FM was driven by the combined effects of the FM-induced mud surface pressure gradient force and saltwater intrusion near the bottom. Weak mixing during the subsequent neap tidal period sustained the FM as it rapidly extended into the middle region of the North Passage. This produced a large velocity shear at the interface of the FM and upper suspension layer, increasing the entrainment from the FM to the upper suspension layer. As a result of the increased tidal mixing, the FM weakened and then finally broke down in the subsequent spring tidal period.

fluid mud
FVCOM
saltwater intrusion
sediment dynamics
simulation
storm impact

http://resolver.tudelft.nl/uuid:f4926d0e-a03b-49c7-ad5c-eadb0b9bf1f3

https://doi.org/10.1029/2019JC015419

2020-09-10

2169-9275

Journal Of Geophysical Research-Oceans, 125 (3)

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

journal article

© 2020 Jianzhong Ge, Changsheng Chen, Zhengbing Wang, Keteng Ke, Jinxu Yi, Ping Xing Ding