Characteristics of the Antarctic Bottom Water Transport through the Vema Fracture Zone Based on Measurements and Numerical Modeling

The results of an investigation of the characteristics of the Antarctic Bottom Water (AABW) transport through the Vema Fracture Zone in the equatorial Atlantic are presented. The expeditionary data primarily collected during the expeditions conducted by the Shirshov Institute of Oceanology of the Russian Academy of Sciences and the Faculty of Geography of Moscow State University are used. The study incorporates direct measurements, results of numerical modeling by INMOM model, and the GLORYS12v1 reanalysis. A comparative analysis of the data from various sources is carried out to evaluate water transport through the Vema Fracture Zone. The role of the Vema Fracture Zone in the propagation of AABW is examined. The main characteristics of near-bottom flows are identified. According to direct measurements, modeling results, and reanalysis data, the AABW transport through the Vema Fracture Zone, using the θ = 1.7°C isotherm as the upper boundary, amounts to 0.9 Sv (measurements), 0.8 Sv (model), and 0.7 Sv (reanalysis). The near-bottom isotherms differ across the data sources. Nevertheless, all data types yield similar estimates of bottom water transport (with a maximum discrepancy of up to 20%), indicating good performance of the numerical modeling in the fracture zone.