Long–Period Trends in Water Temperature Changes in the Northern Part of the Atlantic Ocean according to the Ocean Reanalysis Data

The results of assessing long–term changes in water temperature in the northern part of the Atlantic Ocean (0°–70° N, 8°–80° W) according to the data of ocean reanalyses and objective analyses for the periods of 1961–2011 and 1980–2011 are presented. The obtained estimates are based on the use of a nonparametric method of regression analysis (quantile regression) for the monthly mean ocean temperature for a quantile value of 0.5. In 1961–2011 the warming was mainly recorded in the upper 400-m layer in the region from the equator to 70° N. Over this 51-year period, the increase in the median monthly ocean temperature was ~0.5°C on average in the analyzed water area, while in the Gulf Stream–North Atlantic Current system, it was ~1°C. During the period of 1980–2011, the warming in the northern part of the Atlantic Ocean occurred mainly in the upper 1-km layer at high latitudes (50°–65° N). Over this 32-year period, the median monthly mean ocean temperature increased in the subpolar gyre in the upper 400-m layer by ~1°C.