Mechanisms of Interannual Variability of Ocean Bottom Pressure in the Southern Indian Ocean

Frontiers in Marine Science

Niansen Ou¹  Jianhuang Qin²  Xuhua Cheng²  Duotian Huang²  Yuting Niu²  Chengcheng Yang² 

[1] College of Ocean and Meteorology, Guangdong Ocean University, Zhanjiang, China;College of Oceanography, Hohai University, Nanjing, China;Key Laboratory of Marine Hazards Forecasting, Ministry of Natural Resources, Hohai University, Nanjing, China;

关键词: ocean bottom pressure;    Southern Indian Ocean;    wind forcing;    sea level pressure anomaly;    Ekman transport;   

DOI  :  10.3389/fmars.2022.916592

来源: DOAJ

【 摘 要 】

The study of ocean bottom pressure (OBP) helps to understand the changes in the sea level budget and ocean deep circulation. In this study, the characteristics and mechanisms of interannual OBP variability in the Southern Indian Ocean are examined using Gravity Recovery and Climate Experiment (GRACE) satellite data from 2003 to 2016. Results show that there are two energetic OBP centers in the Southern Indian Ocean (50°–60°S, 40°–60°E and 45°–60°S, 80°–120°E). The OBP magnitudes at two centers have strong variability on interannual time scales, and their values are larger during austral summer (NDJF) and winter (JJAS). Atmospheric forcing plays an important role in local OBP variability. The high (low) sea level pressure (SLP) over the Southern Indian Ocean benefits positive (negative) OBP anomalies via the convergence (divergence) of Ekman transport driven by local wind. Such SLP anomalies are related to the Southern Annular Mode (SAM), Southern Oscillation (SO) and Indian Ocean dipole (IOD). SAM can influence the OBP changes in both austral summer and winter, while SO and IOD have positive correlations with OBP variability during austral summer and austral winter, respectively. These results are validated by a mass-conservation ocean model, which further confirms the importance of atmospheric forcing on the interannual OBP variations.

【 授权许可】

Unknown