Comparative analysis of the long‐term variability of winter surface temperature in the Black and Aegean Seas during 1982–2004 associated with the large‐scale atmospheric forcing

Abstract

Satellite and reanalysis data for the period 1982-2004 were used to study the long-term variability of the winter-mean sea surface temperature (SST) in the Black and Aegean Seas and its connection with the major atmospheric forcing: surface air temperature (SAT), surface wind and North Atlantic Oscillation (NAO) and East Atlantic-West Russia (EAWR) teleconnection patterns. In spite of some differences, the general tendencies of SST variability in both basins are similar. The major climatic event (i.e. SST decreases below the climatic mean followed by the sharp increase of SST, occurred during the period 1986-1999) and its connection with the atmospheric forcing are evident both in the Black and Aegean Seas. During the investigated period, the south-western wind regime occurred over the Black Sea and the northeastern wind regime over the Aegean. It is shown that the variability of the meridional component of the surface wind (which provides the most of the atmospheric heat transport into the basins) is well correlated with the large-scale atmospheric patterns (NAO and EAWR). The major difference is that in the Black Sea the NAO intensification/weakening results in the weakening/strengthening of the southern wind, whereas in the Aegean Sea EAWR/NAO intensification/weakening produce strengthening/weakening of the northern wind. The long-term variability of the SST is well correlated with the variability of the SAT, which in turn is highly correlated with the meridional component of the surface wind. However, a remarkable feature is that in the Black Sea an increase/decrease of the SAT is associated with the strengthening/weakening of the southern wind. On the contrary, in the Aegean Sea, an increase/decrease of the SAT is associated with the weakening/strengthening of the northern wind. The simple basic scheme of influence of the large-scale atmospheric forcing on the long-term SST variability during the positive NAO and EAWR phase is proposed.

Black Sea thermohaline properties: Long‐term trends and variations

“…Monthly mean SSTs from the Pathfinder and CMEMS are first interpolated on our model grid and then the corresponding deep basin averaged values are calculated. The inter‐annual and inter‐decadal variations in the Black Sea hydrography can be identified through analysis of the SST averaged over the interior basin with depths greater than 1500 m during winter (December–March) [ Oguz et al ., and 2006; Kazmin et al ., ; Belokopytov , ]. For this reason, the deep basin average of annual mean SST (ASST) and winter mean (December–March) SST (WSST) are shown in Figures a and b, respectively.…”

Understanding the Impact of Environmental Variability on Anchovy Overwintering Migration in the Black Sea and its Implications for the Fishing Industry

“…When anchovy start migration later, direct pathways to the southeastern overwintering grounds may be inaccessible hence migration success decreases significantly. Cold winters caused by successive cold, dry wind outbreaks blowing from the northern sector of Euro-Asia associated with strong positive modes of NAO (Polonsky et al, 2007;Valchev et al, 2012) and EA-WR (Kazmin et al, 2010) lead to cold air temperatures and sea-water temperatures of below 6 • C on the shelf (Mihailov et al, 2016).…”

Long term trends in the sea surface temperature of the Black Sea

“…In the Black Sea, studies of inter-annual variability of the physical properties are commonly restricted in their time coverage to the last 20 to 50 years, see e.g. (Kazmin et al, 2009 and references therein). Polonsky and Lovenkova (2004) gave a detailed analysis of SST variability and their possible causes over the period of , however their study was limited to a single transect across the Black Sea.…”

“…Polonsky and Lovenkova (2004) gave a detailed analysis of SST variability and their possible causes over the period of , however their study was limited to a single transect across the Black Sea. Potential causes of temperature changes and their link with North Atlantic Oscillations were also discussed by Oguz (2005) and by Kazmin et al (2009). Studies covering longer periods are mostly concerned with changes in the sea as a whole and are based on the analysis of the monthly/yearly mean Sea Surface Temperature (SST) derived from 1 • ×1 • gridded data sets (see Oguz, 2005 and references therein), which in turn were obtained by optimal interpolation from 4 • ×4 • or 2 • ×2 • gridded observations (Rayner et al, 2003 andStephens et al, 2002).…”