Low-frequency variations of the characteristics of pycnocline in the North Atlantic and their correlation with the North-Atlantic oscillation |
| |
Authors: | G F Dzhiganshin A B Polonskii |
| |
Institution: | (1) Marine Hydrophysical Institute, Ukrainian Academy of Sciences, Sevastopol |
| |
Abstract: | On the basis of processing of the oceanographic data accumulated for the water area of the North Atlantic in 1950–1999 (∼500,000
stations), we study seasonal and interannual variations of the principal characteristics of pycnocline within the range of
σt = 25.5–27.5 conventional density units. It is shown that the interannual oscillations of these characteristics in the entire
analyzed layer can be regarded as a superposition of fluctuations with periods from 2–3 to 10–12 yr. The typical ranges of
these fluctuations for the depths of occurrence of isopycnic surfaces and the corresponding temperature and salinity are equal
to 20–25 m, 1–1.5°C, and 0.25‰, respectively. The intensification of atmospheric circulation at middle latitudes is accompanied
by the simultaneous deepening of the pycnocline and its heating in the central part of the North Subtropical Anticyclonic
Gyre. At the same time, the process of weakening of the atmospheric circulation leads to the rise of the pycnocline and its
cooling. The complete cycle of interaction of the North-Atlantic Oscillation with the anomalies of isopycnic characteristics
(with regard for the period of their advection) is equal to ∼6–8 yr.
__________
Translated from Morskoi Gidrofizicheskii Zhurnal, No. 2, pp. 29–48, March–April, 2007. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|