Influences of Deep‐Water Seamounts on the Hydrodynamic Environment in the Northwestern Pacific Ocean

Abstract

AbstractThe presence of seamounts impacts the ocean's hydrodynamic environment. A 5‐year numerical simulation is conducted over the Northwestern Pacific Ocean (NWPO) to investigate the influence of seamounts. The results are validated against satellite remote sensing data and in‐situ measurements. Sensitivity experiments show that the presence of seamounts increases the complexity of the flow field, leading to enhanced relative vorticity, divergence, and strain rate. Additionally, eddy activity is enhanced while eddy propagation is suppressed. Five main physical processes that affect the hydrodynamic environment are examined around the Caiwei (CS), Weijia (WS) and Niulang (NS) seamounts. (a) Seamount‐induced negative vorticities are found above the three seamounts most of the time and extend to about 600 m above the summit of the seamounts; (b) density fronts, a few kilometers in width, are present in the bottom boundary layer of the three seamounts, with accompanying jets occurring at the same locations; (c) seamount‐induced topographic Rossby waves (TRWs) signals are extracted when a 7‐ to 10‐day band‐pass filter is applied to the temperature and velocity anomaly fields around CS (WS and NS) at 5,350 m (5,350 m and 4,500 m); (d) seamount‐eddy interactions result in abundant eddies generated and trapped around the three seamounts; and (e) lee waves are found at the three seamounts. The systematic discussion of these physical processes near the deep seamounts provides a new understanding of how these processes enhance biological connectivity among seamounts.