On the Change in the Sea Surface Temperature in the Benguela Upwelling Region: Part II. Long-Term Tendencies

Izvestiya, Atmospheric and Oceanic Physics - The issue of long-term tendencies in the sea surface temperature (SST) in the Benguela upwelling region and their causes is examined using the daily...     

Mechanism for the Formation of Temperature Anomalies in the Upper Layer of the North Atlantic

ORA-S3 oceanological reanalysis data for 1959–2011 is applied to analyze the role different factors play in forming advective heat transfer anomalies on an interannual–decadal scale in the upper mixed layer of the North Atlantic. Regions are revealed in which horizontal heat advection anomalies are determined by variations in current intensity, temperature gradients, and their joint influence. It is demonstrated that the contribution of different mechanisms responsible for advective heat transfer anomalies in the upper mixed layer to the total anomalies of advective origin varies fundamentally from one current to another in the North Atlantic. In the Gulf Stream area (after it separates from the continental slope), horizontal heat advection anomalies in the upper mixed layer result mainly from fluctuations in current intensity, while in the Caribbean Current and the Gulf Stream area (until its separation), they result from variations in the horizontal temperature gradients in the upper mixed layer. In the Labrador Current, both of these mechanisms have the same sign and approximately the same absolute values. In the East Greenland Current, they compensate each other. The contribution of anomalies in horizontal temperature gradients transferred by anomalous currents to the formation of heat transfer anomalies in the upper layer of the North Atlantic are, on the whole, relatively small throughout the water area. The areas of the North Atlantic and West Greenland currents are exceptions.     

The Spatiotemporal Variability of pH in Waters of the Black Sea

Doklady Earth Sciences - Based on archival data of the Institute of Natural and Technical Systems for the period from 1956 to 2010, the large-scale structure, seasonal variability, and long-term...     

Kinematic structure and transport of currents in the north-western tropical Atlantic

Oceanographic data from the regional data bank, covering a period from 1911 through to 1990, in combination with the climatic tangential wind stress data have been applied to determine the historical fields of summary currents in the north-western tropical Atlantic; currents of the major circulation elements in the active layer have been specified. It has been confirmed that a significant, in terms of climate, transport of surface and subsurface waters by the geostrophic component of the North Brazil current (NBC) to the northern tropical Atlantic does not take place. North-west of 2^oN and 45^o W, the current turns eastward, thus contributing to the generation of the equatorial countercurrent. The transport of the NBC within a 0–500 m layer near 1^o N has been evaluated to be equivalent to 50 Sv, and the mean annual transport of the equatorial countercurrent to 30 Sv. Translated by Vladimir A. Puchkin.     

Mesoscale structure of oceanographic fields in the north-western tropical atlantic ocean

The distribution of the hydrological and hydrochemical characteristics of seawater is analysed and their relationship with the mesoscale structure of geostrophic currents is described based on experimental data derived in 1984–1990 in the north-western tropical Atlantic Ocean. It is shown that anticyclonic eddies which are formed in the region of retroflection of the North Brazilian coastal current (NBCC) are displayed in a different manner in the field of hydrological characteristics at the surface and in the subsurface layer. Therefore satellite data, which reflect the qualitative pattern of the surface circulation, do not always represent correctly the circulation in the entire ocean's active layer or the integral processes. The observations that have been made up to now do not permit us to state that the eddy-wave transport plays an essential role in the outflow of warm equatorial waters in the north-western tropical Atlantic.Translated by Mikhail M. Trufanov.     

Interannual oscillations of the seasonal sea surface temperature variability parameters in the Atlantic Ocean

This paper reports on the interannual fluctuations of the seasonal sea surface temperature (SST) variability in the North Atlantic. The areas of intense variation of the average annual SST and predominant harmonic (annual and biannual) amplitude have been identified. A significant negative correlation between the average annual SST and the amplitude of the SST variation annual harmonic is demonstrated in thesee areas; amplitude anomalies of the dominating harmonics of interannual SST fluctuations may exceed the climatic norm by 1.5–2.0 times.Translated by Mikhail M. Trufanov.     

Mass balance and heat transport in the equatorial Atlantic

The annual average mass and heat balances in the equatorial Atlantic as well as their seasonal variability are analysed using adaptation (initialization procedure) data. It is shown that correlations of temperature and the seasonal fluctuations of the meridional velocity component do not significantly affect the annual average meridional heat transport.Translated by Mikhail M. Trufanov.     

El Niño in 1991–1992 and its manifestations in the tropical Atlantic

A variety of anomalous conditions in the tropical Pacific and Atlantic oceans during the 1991–1992 El Niño event are described. The current El Niño is shown to have specific features, evident in the behaviour of the southern oscillation index and sea surface temperature of the equatorial Pacific Ocean. Also, it was accompanied by warming of the eastern tropical Atlantic. Temperature anomalies of the tropical Atlantic surface water temperature reached their maximum (>3°C) in May–June 1991, i.e. 2–3 months earlier than in the Pacific Ocean.Translated by V. Puchkin.     

Thermohaline circulation in the North Atlantic and its simulation with a box model

Features of the North Atlantic thermohaline circulation response to periodic, stochastic, and instantaneous forcing are studied using a four-box model. The present-day circulation is shown to be characterized by a stable quasi-periodic oscillatory mode that manifests itself as the Atlantic Multidecadal Oscillation. The thermohaline catastrophe is unlikely in the modern climate epoch.