Empirical orthogonal functions in heat contents of the World Ocean energetically active zones

Abstract

Based on data from the Met Office Hadley Centre, we studied variations in heat content of the upper active layer (UAL) at middle and high latitudes of the World Ocean using the method of empirical orthogonal functions (EOF). The maximum contribution to the UAL heat contents is provided by the first harmonic that refers to seasonal variations. We analyzed features of spatial distribution of the UAL heat content seasonal variations for the first few EOF modes. Meridional structures are descriptive of the first harmonic. One can observe the first vector maxima in the Atlantics south-western part and in the zone of its eastern coast, and in the Pacific north-western part. Differences in thermal regime between the Atlantics and Pacific western and eastern parts may be due to radiation heating and systems of warm currents. The second and third harmonics have zonal structures.