Physical Oceanography, Vol. 13, No. 3, 2003
EFFECT OF THE SOUTHERN OSCILLATION ON THE VARIABILITY
OF THE SURFACE TEMPERATURE AND PRESSURE IN THE
ATLANTIC-EUROPEAN REGION IN SPRING
A. B. Polonskii, E. N. Voskresenskaya, D. V. Basharin, and N. V. Mikhailova
On the basis of reanalysis of the data of the European Center of Medium-Range Weather Fore-
casts for 1979–1993, we study the relationship between the interannual and intramonthly varia-
bility of the fields of surface temperature and pressure in the Atlantic-European region and the
Southern Oscillation (SO). In spring, the SO is responsible for
of the variance of surface
temperature for periods of
in the east part of Europe and in the Mediterranean region.
In this case, the zonal circulation over the North Atlantic is intensified, which manifests itself in
the deepening of the Iceland Low and Azores High. For low indices of SO,
ture fluctuations are predominant over the Black-Sea region. At the same time, 3–4-week
fluctuations are predominant over West Mediterranean. An important role in the formation of
abnormal temperature conditions in the analyzed region is payed by the events of La Niño.
Among the most striking and practically important examples of the influence of large-scale interaction be-
tween the ocean and atmosphere on global climatic changes with time scales of
one should necessarily
mention the phenomenon of El Niño and Southern Oscillation (ENSO). This phenomenon can be described as a
process of elevation of temperature of equatorial waters in the Pacific Ocean (exceeding
on the surface)
running for at least
months and playing a significant role in global climatic variations. The ENSO events
alternate in time with the events of La Niño (LN), which, on the contrary, are connected with lowering of the
temperature of equatorial waters in the Pacific Ocean. The magnitude of negative temperature anomalies on the
ocean surface caused by LN rarely exceeds
Thus, their absolute values are lower than the absolute val-
ues of positive anomalies caused by the ENSO. This explains the fact that the literature devoted to the analysis
of the ENSO events is much more extensive [1–7]. However, this in no case means that the LN events do not
have global climatic consequences. In fact, they are well pronounced .
The mechanism of the influence of tropical temperature anomalies on the global atmospheric circulation is
now fairly well studied. For the first time, it was described by Bjerknes  and then developed in numerous
works (see, e.g., [2, 9] and the bibliography therein). Actually, this mechanism is connected with the generation
of large-scale atmospheric disturbances accompanying the development of large-scale thermal anomalies in the
Pacific Ocean and affecting the processes running throughout the world. The response of the atmosphere exists
in the form of both stationary Rossby waves and atypical nonstationary eddy structures [3, 9, 10].
It is worth noting that the number of works devoted to the investigation of the effect of ENSO on the Atlan-
tic-European region permanently increases and, in some case, one can encounter even contradictory results.
Thus, some authors deny the existence of a noticeable influence of EN on circulation in the analyzed region .
At the same time, the authors of [12–15] have an absolutely opposite opinion.
The anomalous atmospheric processes running in the mature phase of the ENSO in winter of the Northern
Hemisphere were studied in [16, 17]. In the present work, a similar analysis is carried out for spring. Our aim is
Marine Hydrophysical Institute, Ukrainian Academy of Sciences, Sevastopol. Translated from Morskoi Gidrofizicheskii Zhurnal,
62, May–June, 2003. Original article submitted February 27, 2002; revision submitted March 22, 2002.
0928-5105/03/1303–0171 $25.00 © 2003 Plenum Publishing Corporation 171