Abstract
As the Gulf Stream separates from the coast near Cape Hatteras, it meanders in the east-northeast direction for the next 2500-3500 km and beyond across the Atlantic. During this journey the jet is free and is subjected to the overlying atmospheric winds, while affecting processes from fisheries to atmospheric events and is an indicator of climate change. A distribution of the 27-year wind stress curl (WSC) field is taken over the domain of 80°W to 45°W and 30°N to 45°N from 1980 to 2019 to quantify the values of the strongest positive WSC. This WSC maxima is represented as 1.3 (~90 percentiles) to 3.5 standard deviations (80-210) x 1E-09 Pa/m from the mean of the distribution from the mean of the WSC field. Five-year averaged WSC maxima area features an increase from 170,000 sq. km (~3% of the domain) in 1985-1989 to 394,000 sq. km (~7% of the domain) in 1995-1999. The average area of 2015-2019 is the last and largest in the time series with a value of about 520,000 sq. km, covering ten percent of the domain. Latitudinal variation of the maxima region (>80 x 1.E-06 Pa/km) center of mass (COM) features a slope of 0.01 degrees per year, or a 40 km northward movement over forty years. COM longitude experiences dampening centered around 60°W and 80 km movement west over 40 years. Based on 27 years (1993-2019) of reanalysis wind and satellite altimetry data for the Gulf Stream path, we present observational evidence that the path of this freely meandering jet follows the region of maximum cyclonic vorticity (known as the positive vorticity pool) of the wind stress field. This synchronicity is valid over times-scales from months to decades.