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The influence of the atmospheric circulation on the winter air-sea heat fluxes over the northern Red Sea is investigated during the period 1985-2011. The analysis based on daily heat flux values reveals that most of the net surface heat exchange variability depends on the behavior of the turbulent components of the surface flux (the sum of the latent and sensible heat). The large-scale composite sea level pressure (SLP) maps corresponding to turbulent flux minima and maxima show distinct atmospheric circulation patterns associated with each case. In general, extreme heat loss (with turbulent flux lower than 2400 W m 22) over the northern Red Sea is observed when anticyclonic conditions prevail over an area extending from the Mediterranean Sea to eastern Asia along with a recession of the equatorial African lows system. Subcenters of high pressure associated with this pattern generate the required steep SLP gradient that enhances the wind magnitude and transfers cold and dry air masses from higher latitudes. Conversely, turbulent flux maxima (heat loss minimization with values from 2100 to 250 W m 22) are associated with prevailing low pressures over the eastern Mediterranean and an extended equatorial African low that reaches the southern part of the Red Sea. In this case, a smooth SLP field over the northern Red Sea results in weak winds over the area that in turn reduce the surface heat loss. At the same time, southerlies blowing along the main axis of the Red Sea transfer warm and humid air northward, favoring heat flux maxima.

Robust surface warming with distinct interdecadal variations has been observed in the offshore area of China and adjacent seas (hereafter, offshore China) during winter and summer of the period 1958–2014. Acceleration of this warming during 1980–99 at rates greater than the global mean warming rate was accompanied by a weakening of the East Asian monsoon (EAM) and a strengthening of the west Pacific subtropical high (WPSH). It was determined that the sea surface temperature (SST) variation in offshore China correlates very well with changes in the EAM wind on interdecadal time scales. It was also established that the enhanced oceanic lateral heat transfer, mainly attributed to the leading empirical orthogonal function (EOF1), weakening EAM wind mode, has a central role in robust interdecadal winter surface warming in offshore China. However, except for the effect of oceanic lateral heat transfer, the increased surface heat flux through radiative heating related to the third EOF (EOF3) strengthening EAM anticyclone wind mode (WPSH) in summer appears to have a greater contribution to interdecadal summer surface warming in offshore China. These results help clarify the relationship between interdecadal SST variations, EAM, oceanic currents, and sea surface flux in offshore China.

The impacts of various climate modes on the Red Sea surface heat exchange are investigated using the MERRA reanalysis and the OAFlux satellite reanalysis datasets. Seasonality in the atmospheric forcing is also explored. Mode impacts peak during boreal winter [December-February (DJF)] with average anomalies of 12-18 W m 22 to be found in the northern Red Sea. The North Atlantic Oscillation (NAO), the east Atlanticwest Russia (EAWR) pattern, and the Indian monsoon index (IMI) exhibit the strongest influence on the airsea heat exchange during the winter. In this season, the largest negative anomalies of about 230 W m 22 are associated with the EAWR pattern over the central part of the Red Sea. In other seasons, mode-related anomalies are considerably lower, especially during spring when the mode impacts are negligible. The mode impacts are strongest over the northern half of the Red Sea during winter and autumn. In summer, the southern half of the basin is strongly influenced by the multivariate ENSO index (MEI). The winter mode-related anomalies are determined mostly by the latent heat flux component, while in summer the shortwave flux is also important. The influence of the modes on the Red Sea is found to be generally weaker than on the neighboring Mediterranean basin.

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During four seasonal surveys in 1997–1998 the shelf circulation is dominated by a semipermanent cyclone originating in the higher‐salinity waters from lower Aegean latitudes. Another cyclone in the Sporades Basin has the same origin and has a semipermanent nature in the upper ∼200 m, while it is robust in all deeper layers. The variability in the upper ∼200 m depends strongly on the local river discharge and on the inflow of Black Sea Water (BSW) (evident in summer and autumn). Consequently, the shelf cyclone coexists with anticyclones in the vicinity of the river mouths (February 1998 and May 1997) or coexists with an anticyclone due to BSW (September 1997). In July 1997 the upper ∼20 m of the entire shelf is occupied by an anticyclone of BSW. The deep part of the Sporades Basin cyclone has possibly originated by deep water formation and spreading in the central north Aegean in the early 90s. In the numerical experiments the northern rivers form one plume that tends to occupy the northernmost part of the shelf due to the smaller domain scales therein. The western river (Pinios) plume expands north of the discharge site due to the abrupt shelf slope near the river mouth. Northerly winds can merge the northern and western river plumes, as in February 1998, while southerly winds can restrict the southward coastal current, thus separating northern and western river plumes, as in May 1997. A northward momentum imposed by an external Aegean flow along the east coast influences the spreading of north and west plumes.

The influence of the winter atmospheric circulation on the turbulent variables of the air‐sea boundary layer in the Mediterranean Sea is investigated. We examine the effects of several climatic indices and the corresponding large scale atmospheric patterns on the above variables by using a correlation analysis. The spatial characteristics and the behavior of the turbulent variables are also examined based on standard deviation and EOF analysis. Two main types of response to the index‐specified atmospheric patterns have been identified: (1) A relatively uniform response of the entire basin associated with the influence of the East Atlantic pattern and (2) opposite responses in the western and eastern sub‐basins linked mainly to the intrabasin SLP. The latter is a combined effect of the first four modes of atmospheric variability in the North Atlantic/Eurasia region, the North Atlantic Oscillation (NAO), the East Atlantic Pattern (EA), the Scandinavian Pattern (SCAND), and the East Atlantic‐West Russia Pattern (EAWR). The two identified responses of the Mediterranean Sea to the atmospheric forcing are also in accordance with the primary modes of variability of the turbulent variables that result in the EOF analysis. All of the statistically independent indices (NAO, EA, SCAND, EAWR) have to be considered in order to fully account for the modulation of the turbulent variables in the Mediterranean Sea. As an example we refer to the mechanism through which, independent modes of atmospheric variability contributed to the Eastern Mediterranean Transient event between 1987 and 1995.