EGU22-3460
https://doi.org/10.5194/egusphere-egu22-3460
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Temporal variability of Multimodal Internal Tides at the East China Sea Shelf

Weidong Wang, Robin Robertson, Yang Wang, Chen Zhao, Jia You, Zhenhua Xu, and Baoshu Yin
Weidong Wang et al.
  • Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China (wangweidong@qdio.ac.cn)

Internal tide variations and mixing properties are important to shelf dynamics and mass exchange. In the present study, spatiotemporal variability of internal tides and their modulation factors on the southern East China Sea (ECS) shelf are examined using a three-month mooring observation. Semidiurnal and diurnal internal tides are found to exhibit distinct varying trends. Specifically, the semidiurnal internal tides are quite weak at the early stage, but greatly enhanced in the last three spring-neap cycles. In contrast, the diurnal internal tides follow quasi spring-neap variability except for the strengthening in two specific periods. The enhancement of semidiurnal internal tides in late July and August can be attributed to the strengthened stratifications shelf-slope area northeast of Taiwan Island, which is identified as the generation source. While the diurnal internal tides are modulated by background circulation through the effective critical latitude. The weak critical latitude effect corresponds to the intermittent enhancement of diurnal internal tides in two specific periods. In addition, the circulation also affects the vertical modal structures of the internal tides. The proportion of higher modes internal tides increases during robust eddy activities.  The high-frequency and high-mode internal tides are of crucial significance for turbulent mixing on the shelf region.

Key word: Internal Tides; Mooring Observation; Spatiotemporal variation; Shelf dynamics

How to cite: Wang, W., Robertson, R., Wang, Y., Zhao, C., You, J., Xu, Z., and Yin, B.: Temporal variability of Multimodal Internal Tides at the East China Sea Shelf, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-3460, https://doi.org/10.5194/egusphere-egu22-3460, 2022.