Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 Oceanologia

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Ventilation of the Baltic Sea deep water : A brief review of present knowledge from observations and models

Meier H. E. M., Feistel R., Piechura J., Arneborg L., Burchard H., Fiekas V., Golenko N., Kuzmina N., Mohrholz V., Nohr C., Paka V. T., Sellschopp J., Stips A., Zhurbas V.

Oceanologia

2006

No. 48 (S)

133-164

The ventilation of the Baltic Sea deep water is driven by either gale-forced barotropic or baroclinic salt water inflows. During the past two decades, the frequency of large barotropic inflows (mainly in winter) has decreased and the frequency of medium-intensity baroclinic inflows (observed in summer) has increased. As a result of entrainment of ambient oxygen-rich water, summer inflows are also important for the deep water ventilation. Recent process studies of salt water plumes suggest that the entrainment rates are generally smaller than those predicted by earlier entrainment models. In addition to the entrance area, the Słupsk Sill and the Słupsk Furrow are important locations for the transformation of water masses. Passing the Słupsk Furrow, both gravity-driven dense bottom flows and sub-surface cyclonic eddies, which are eroded laterally by thermohaline intrusions, ventilate the deep water of the eastern Gotland Basin. A recent study of the energy transfer from barotropic to baroclinic wave motion using a two-dimensional shallow water model suggests that about 30% of the energy needed below the halocline for deep water mixing is explained by the breaking of internal waves. In the deep water decade-long stagnation periods with decreasing oxygen and increasing hydrogen sulphide concentrations might be caused by anomalously large freshwater inflows and anomalously high mean zonal wind speeds. In different studies the typical response time scale of average salinity was estimated to be between approximately 20 and 30 years. The review summarizes recent research results and ends with a list of open questions and recommendations.

Warm waters of summer 2002 in the deep Baltic Proper

Feistel R., Nausch G., Mohrholz V., Łysiak-Pastuszak E., Seifert T., Matthäus W., Krüger S., Hansen I. S.

Oceanologia

2003

No. 45 (4)

571-592

From October 2002 until March 2003 surprisingly warm, oxygenated waters were frequently encountered in the Baltic Sea in the area between the Bornholm and Fa*rö Deeps from the halocline down to the bottom. Owing to their ventilation effect in the stagnating deep waters, their occasional observations have partly been incorrectly attributed to the inflow events of October 2002 or January 2003. The emergence of some of these waters can be traced back to the exceptional summer weather conditions in August and September 2002 in central Europe. The warm waters played a remarkable renewal pacemaker role for the subsequent important winter inflow of January 2003. The evolution of this summer inflow is described and possible causes are discussed.