Variability of Sea Level and Circulation in the North Atlantic Based on Satellite Altimetry Data

摘要

This paper discusses the relationship between interannual sea level fluctuations and the system of currents in the area of the North Atlantic Anticyclonic Water Gyre according to satellite altimetry (1993-2019). The initial data was the base of monthly average data on the sea level of the Copernicus reanalysis archive GLOBAL_REANALYSIS_PHY_001_030. A clearly expressed relationship between the annual discharges of the Florida Current and the level gradient in the section of 25° latitude between 80°-78° W was revealed (r = 0.79). Calculation of interannual sea-level changes on the latitudinal section 26° for its individual sections and across the entire North Atlantic within 80°-15° W, which is a reference in the monitoring of the Atlantic meridional overturning circulation (AMOC), was performed. Annual estimates of level gradient Ah and its average values h_(aw) between the extreme points of the sections were considered. A high positive correlation between Ah and h?y was revealed for sections 70°-25° W (r = 0.81) and 80°-15° W (r = 0.71), as well as the North Atlantic Oscillation with Ah and h_(av) on these sections. It is shown that, despite the sharp weakening of the AMOC until 2010, later, its relative power recovers almost to the average value. Obviously, the weakening of AMOC until 2010 is only the negative phase of its longer fluctuations. Statistical parametriza-tion of average annual values of water transport at a latitude of 26° N was performed to the north and south (AMOC and Q_(umo)) according to sea-level data at this latitude. Regression equations are obtained, which, according to the Ah and h_(av) data, quite accurately (77-92%) describe the dispersion of the AMOC and Q_(umo) time series.