Unraveling Regional Patterns of Sea Level Acceleration over the China Seas

Abstract

Accelerated sea level rise is placing coastal communities in a vulnerable position; however, the processes underlying sea level acceleration in China remain uncertain. In this study, we examine the sea level acceleration and its contributors over the China Seas. We calculate acceleration along the Chinese coast using satellite altimetry and tide gauge records. During the satellite altimetry era, sea level acceleration from tide gauge records varies across all stations, reaching up to 0.30 ± 0.20 mm/yr2, while satellite altimetry could underestimate/overestimate the sea level acceleration in most locations. Acceleration near the coast, except in the Bohai Sea, is mainly driven by changes in the mass component. In contrast, for the open ocean, changes in steric sea level are the main contributor to sea level acceleration. The evolution of spatial acceleration patterns over the China Seas reveals that the ENSO and PDO variabilities dominate the changing patterns of sea level acceleration in the open ocean, including the Philippine Sea through steric sea level, and changes in most coastal locations are due to the non-steric component.

Analysis of sea level variability and its contributions in the Bohai, Yellow Sea, and East China Sea

“…In Figure 7D, the lines following the LVs and PCTS recombination and the adjusted steric component are fitted to the curves, peaking around 2010, with a proportion ranging from 20% to 25%, with an average value of 11.17%, in line with the findings of Qu et al (2019). Previous studies also found that increasing ocean mass accounts for a greater proportion of the drivers of sea level change in the BYECS, and it dominates the contribution to the change in sea level trend (Chang et al, 2017;Qu et al, 2023).…”

“…These findings align with previous conclusions, emphasizing steric sea level as the primary influencing factor of ECS sea level variation. The central and eastern parts of the ECS are influenced by the high-temperature and highsalinity outer seawater introduced by the Kuroshio (Zhang et al, 2014;Chang et al, 2017;Qi et al, 2018;Qu et al, 2023). The Taiwan Strait, due to its shallow depth, is affected by both circulation and local wind (Qi et al, 2017;Liu Z. et al, 2021).…”