Hans-Ulrich Lass

The Baltic Sea 1994—Consequences of the hot summer and inflow events

The temperatures in the western and central Baltic Sea were determined by the relatively mild winter 1993/94 causing positive anomalies of 0.5–1 K in both the surface layer and the intermediate water. The summer 1994 was among the warmest in the past 60 years and produced extremely high temperatures and anomalies of 4–6 K in the surface layer of the whole Baltic Sea.

The Baltic Sea in 1995— Beginning of a new stagnation period in its central deep waters and decreasing nutrient load in its surface layer

Positive anomalies of the surface heat flux caused by the mild winter and warm summer influenced temperatures in the surface layer and in the cold intermediate water of the Baltic Sea in 1995. The water exchange across the sills in the entrances to the Baltic Sea was relative small in comparison with the years before. That favours the beginning of a new stagnation period in central Baltic deep waters.

Die hydrographisch-chemischen Bedingungen in der westlichen und zentralen Ostsee im Jahre 1993

Der Salzwassereinbruch im Januar 1993 war von herausragender Bedeutung fur die hydrographischchemischen Bedingungen in den untersuchten Ostseeregionen. Er fuhrte vor allem im Tiefenwasser des Bornholmbeckens und des Danziger Beckens zu einer starken Zunahme der Salz- und Sauerstoffkonzentrationen. Seine Auswirkungen auf das ostliche Gotlandbecken waren schwacher und im Gotlandtief durch starke Fluktuationen der chemischen Parameter gepragt. Nur Anfang Juli war auf dieser Station die gesamte Wassersaule kurzzeitig frei von Schwefelwasserstoff.

The major Baltic inflow in January 1993 — Measurements and modelling results

Major Baltic inflows (from the Kattegat) represent the only possibility for deep water renewal in the Baltic Sea that is generally characterised by stable stratification. Such an inflow occurred in January 1993 for the first time in 16 years. Observations were made by a moored station at Dars Sill and, for the first time since investigations into major Baltic inflows began, by a research vessel. In addition, the event has been simulated in an operational model.