Correlation between the low-frequency variability of surface temperature and the heat flux through the surface in the North Atlantic

Abstract

Using the data of UWM/COADS (University of Wisconsin-Milwaukee/Comprehensive Ocean—Atmosphere Data Set), we have performed cluster and spectral analyses of the average monthly anomalies of temperature and heat balance of the surface of the Atlantic Ocean in three frequency ranges (intraannual, interannual, and decadal). It is shown that these anomalies are closely related on intraannual scales, where the anomalies of the surface temperature of the ocean can be regarded as a result of the direct local generation by heat balance anomalies. The generation mechanism is explained within the known Hasselman model [1, 2]. On interannual scales, this mechanism is not valid, and nonlocal effects related to heat advection become important. On decadal scales, the local generation of anomalies of the surface temperature of the ocean is insignificant, local correlation between fluctuations of heat balance and the surface temperature of the ocean is completely broken, and the spatial structure of anomalies of the surface temperature of the ocean is governed by the global system of currents, which redistributes heat flux from the ocean to the atmosphere. Violations of the local correlation between anomalies of heat balance and the surface temperature of the ocean are observed on intraannual scales in regions with powerful jet currents and in the equatorial region. In some parts of the World's ocean with weak advection, the correlation between heat balance and the surface temperature of the ocean persists up to a decadal period.