Wintertime buoyancy forcing, changing seawater properties, and two different circulation systems produced in the Adriatic

Abstract

[1] Measurements performed in winter 2002/2003 and spring 2003 off the east Adriatic coast showed that the East Adriatic Current (EAC) peaked in January/February (as expected from previous findings) and again in May (not expected). The first maximum corresponded with the considerable cross-shore variability of seawater properties, the colder, fresher water prevailing close to the coast, the warmer, saltier water dominating the open sea. The second maximum coincided with the massive intrusion of warm, saline water from the south Adriatic. Meteorological and hydrologic forcing was anomalous over the measurement interval: during winter 2002/2003 the cooling and river outflows were strong, during spring 2003 the pronounced warming coincided with exceptional dryness. In order to interpret the two EAC maxima a simple numerical model reproducing response of the Adriatic-Mediterranean system to the wintertime forcing was developed. It was found that the first maximum could be related to the coastal freshwater input and offshore evaporation in the Adriatic area, and that the second maximum was probably due to the wintertime surface cooling of the Adriatic while warmer conditions prevailed above the Mediterranean. The resulting horizontal density gradients supported two different circulation systems, one within the Adriatic, the other between the Adriatic and east Mediterranean, and they differed not only in spatial but also in temporal scales, therefore supporting the occurrence of two distinctive EAC maxima.Citation: Orlić, M., et al. (2006), Wintertime buoyancy forcing, changing seawater properties, and two different circulation systems produced in the Adriatic,

Response of the Adriatic Sea to the atmospheric anomaly in 2003

“…5 and 6). A major departure from the climatological values can be observed in May and June at the surface, when surface salinity, according to climatology, has a minimum, due to a spring maximum in river runoff (Raicich, 1996). As no river maximum occurred in spring 2003, due to low precipitation in the region, the surface salinity was constantly increasing till October, to about 38.8.…”

“…This dipole behaviour seems to play a dominant role in climate variability over the Mediterranean basin, being documented by a comparison of temperature, precipitation, circulation and other parameters between the Western and Eastern Mediterranean. There are other recent definitions of MO in which the authors tried to explain atmospheric dynamics over the whole Mediterranean (Palutikof, 2003;Brunetti et al, 2002). The new WeMO defined by Martin-Vide and Lopez-Bustins (2006) as the difference in sea-level pressure between the Cádiz Gulf and northern Italy, describes precipitation fluctuations over the western Mediterranean better than the NAO.…”

Changes in the Adriatic oceanographic properties induced by the Eastern Mediterranean Transient

“…Moreover, a massive outflow of dense water from a basin is known to generate a lagged response of a thermohaline cell in anti-estuarine circulation systems. It is known that the Adriatic dense water outflow, occurring during winter and spring, induces a peak in the counter-flow lagging for several months (Orlić et al, 2007). Aside from the difference in size of the Adriatic and Eastern Mediterranean Basins and their thermohaline cells, the same physics is presumably present during massive generation of dense waters in the Eastern Mediterranean: the EMT generated a massive outflow to the Western Mediterranean over the Sicily Strait, presumably inducing a lagged massive counter-transport of waters in the upper layer.…”

Modelling origin and transport fate of waste materials on the southeastern Adriatic coast (Croatia)

“…It is worth to say that wind forcing, when pronounced, dominate over all other forcing contributions and dynamically shape the sea surface current system found in the Adriatic Sea. The surface wind jets and wakes of the bura wind have a profound effect on the surface currents (Orlić et al, 1994;Pullen et al, 2003), while jugo wind is well known to influence WAC flow reversals (Orlić et al, 2007;Poulain et al, 2004). It is therefore important to force the ocean model with a high resolution wind field that resolves high resolution wind features developed due to interaction of large scale dynamics with local mountains.…”