Fresh oxygen for the Baltic Sea — An exceptional saline inflow after a decade of stagnation

Mohrholz, Volker; Naumann, Michael; Nausch, Günther; Krüger, Siegfried; Gräwe, Ulf

doi:10.1016/j.jmarsys.2015.03.005

Cited by 236 publications

(237 citation statements)

References 27 publications

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“…The ice data used in this study are based on 8564 manually analyzed ice maps from the period 1914-2016. NAO data were taken from Jones et al (1997) with updates from Osborn (2004Osborn ( , 2006Osborn ( , 2011. MBI data were taken from Matthäus et al (2008), with the latest updates from Mohrholz et al (2015) and Nauman et al (2018).…”

Section: Observations and Other Datamentioning

confidence: 99%

100 years of atmospheric and marine observations at the Finnish Utö Island in the Baltic Sea

et al. 2018

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Abstract. The Utö Atmospheric and Marine Research Station introduced in this paper is located on Utö Island (59 • 46.84 N, 21 • 22.13 E) at the outer edge of the Archipelago Sea, by the Baltic Sea towards the Baltic Proper. Meteorological observations at the island started in 1881 and vertical profiling of seawater temperature and salinity in 1900. Since 1980, the number of observations at Utö has rapidly increased, with a large number of new meteorological, air quality, aerosol, optical and greenhouse gas parameters, and recently, a variety of marine observations. In this study, we analyze long-term changes of atmospheric temperature, cloudiness, sea salinity, temperature and ice cover. Our main dataset consists of 248 367 atmospheric temperature observations, 1632 quality-assured vertical seawater temperature and salinity profiles and 8565 ice maps, partly digitized for this project. We also use North Atlantic Oscillation (NAO), major Baltic inflow (MBI) and Baltic Sea river runoff data from the literature as reference variables to our data. Our analysis is based on a statistical method utilizing a dynamic linear model. The results show an increase in the atmospheric temperature at Utö, but the increase is significantly smaller than on land areas and has taken place only since the early 1980s, with a rate of 0.4 • C decade −1 during the last 35 years. We also see an increase in seawater temperatures, especially on the surface, with an increase of 0.3 • C decade −1 for the last 100 years. In deeper water layers, the increase is smaller and influenced by vertical mixing, which is modulated by inflow of saline water from the North Sea and freshwater inflow from rivers and by wind-driven processes influenced by the local bathymetry. The date when air temperature in the spring exceeds +5 • C became 5 days earlier from the period 1951-1980 to the period 1981-2010 and the date when sea surface water temperature exceeds +4 • C changed to 9 days earlier. Sea ice cover duration at Utö shows a decrease of approximately 50 % during the last 35 years. Based on the combined results, it is possible that the climate at Utö has changed into a new phase, in which the sea ice no longer reduces the local temperature increase caused by the global warming.

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Section: Observations and Other Datamentioning

confidence: 99%

100 years of atmospheric and marine observations at the Finnish Utö Island in the Baltic Sea

et al. 2018

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“…The two occasions of sudden salinity increase in the Gotland Deep in April 2015 (Holtermann et al, 2017) and in February 2016 (Figure 6) marked arrivals of the 2014 December (Mohrholz et al, 2015) and 2015 November (Naumann et al, submitted) MBI waters. Another, 2016 January-February MBI did not reach the near bottom layer of the Gotland Deep, as it was not dense enough to replace near-bottom waters from previous MBIs in the Gotland Deep.…”

Section: Discussionmentioning

confidence: 95%

“…Salinity peaked at 13.60 g kg −1 during the first event and 14.11 g kg −1 during the second event in the near-bottom layer of the Gotland Deep. Salinity was last time that high in the Gotland Deep after the 1951 MBI (Fonselius and Valderrama, 2003), which is considered the strongest inflow event in the record from 1880 ( Franck et al, 1987;Matthäus and Franck, 1992;Fischer and Matthäus, 1996;Mohrholz et al, 2015). The highest salinity values during the study period in the near bottom layer of the Fårö Deep (12.79 g kg −1 ), Northern Deep (11.92 g kg −1 ), and Northern Baltic Proper (Kõpu West, 11.77 g kg −1 ) were registered in May 2016, July 2016 and August 2016, respectively.…”

Section: Discussionmentioning

confidence: 99%

“…Since the 1980s, MBIs have been rather rare-strong MBIs occurred in 1993 (Matthäus and Lass, 1995) and 2003 (Feistel et al, 2006) and a moderate MBI in 1997 (Hagen and Feistel, 2001). The following inflow event in December 2014 was considered as the strongest since 1951 (Mohrholz et al, 2015). During this MBI event 320 km 3 of salty and oxygenrich water propagated into the western Baltic Sea after a 10-year stagnation period.…”

Section: Introductionmentioning

confidence: 99%

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Propagation of Impact of the Recent Major Baltic Inflows From the Eastern Gotland Basin to the Gulf of Finland

et al. 2018

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“…(4) and (5) 1990 1991 1992 1992 1993 1994 1995 1996 1997 1998 1999 Because the North Sea is the source of salt in the Baltic Sea, the flow through the Danish Straits is the most important driver of the salt exchange between Kattegat and the South-West Baltic. The two main straits, Sund and Langeland Belt, are the main passages for the salt transport into the Baltic (in example Lehmann et al (2004); Mohrholz et al (2015)). The flow through Sund is mostly driven by the sea level pressure difference between the southern and northern entrances, and can be calculated 15 from the semi-empirical expression:…”

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confidence: 99%

An Evaluation and Implementation of the Regional Coupled Ice-Ocean Model of the Baltic Sea

Jakacki

Meler

2017

Preprint

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Abstract. A three dimensional, regional coupled ice-ocean model based on the open-source Community Earth System Model has been developed and implemented for the Baltic Sea. The model consists of 66 vertical levels and has a horizontal resolution of approx. 2.3 km. The paper focuses on sea ice component results but the main changes have been introduced in the ocean part of the coupled model. The hydrodynamic part, being one of the most important components, has been also presented and validated. The ice model results were validated against the radar and satellite data, and the method of validation based on 5 probability was introduced. In the last two decades satellite and model results show an increase in the ice extent over the whole Baltic Sea, which is an evidence of a negative trend in air temperature in recent decades and increasing of winter discharge from the catchment area.

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Fresh oxygen for the Baltic Sea — An exceptional saline inflow after a decade of stagnation

Cited by 236 publications

References 27 publications

100 years of atmospheric and marine observations at the Finnish Utö Island in the Baltic Sea

100 years of atmospheric and marine observations at the Finnish Utö Island in the Baltic Sea

Propagation of Impact of the Recent Major Baltic Inflows From the Eastern Gotland Basin to the Gulf of Finland

An Evaluation and Implementation of the Regional Coupled Ice-Ocean Model of the Baltic Sea

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