6 The Gulf of Finland
217
An adequate representation of such a complicated multi-layered circulation
needs refined and tailored schemes not only for mesoscale motions but also for
the description of vertical turbulence in the Gulf of Finland. The methods for its parameterization used in contemporary circulation models of the Baltic Sea are taken
from general ocean models and do not necessarily fit the specific conditions in the
gulf. Several studies have suggested that the improper replication of the vertical turbulence might be a major reason for the mismatch of the model results and measurements in the Baltic (Myrberg et al. 2010a). An improvement of this shortcoming has
a large potential for a more reliable replication of both the dynamical and statistical
features of current-driven transport of various pollutants and contaminants.
Finally, we would like to emphasize that the processes affecting the long-term
mean surface circulation and its modelled or observed outcome in the Gulf of Finland are essentially non-linear and exhibit a number of sophisticated feedbacks. For
example, the wind-independent baroclinic mean circulation and the mean winddriven circulation interact with each other in a highly non-linear manner and it is
virtually impossible to specify which one is more important. Moreover, the answer
to this question depends on the case studied and on the time scale under investigation. The circulation studies set extremely high demands for the modelling work and
measurement campaigns not only because of the small internal Rossby radius in this
basin but, perhaps more importantly, due to the above-mentioned complex dynamics that is not directly evident from simple scaling exercises. The role of the model
resolution becomes clearly evident in the following chapters that are dedicated to
detailed studies of circulation and associated transport and drift properties.
Acknowledgements This study was performed in the framework of the BalticWay project, which
was supported by the Estonian Science Foundation, the Academy of Finland and by funding from
the European Commission’s Seventh Framework Programme (FP7 2007–2013) under grant agreement No. 217246 made with the joint Baltic Sea research and development programme BONUS.
The research was partially supported by the Estonian Science Foundation (grant No. 9125), targeted financing by the Estonian Ministry of Education and Research (grant SF0140007s11), and by
the European Regional Development Fund via support to the Centre of Excellence for Non-linear
Studies CENS. The authors are particularly grateful to Dr. J. Laanemets and to an anonymous
reviewer for highlighting several gaps and misinterpretations in the original version of the chapter.
References
Alenius P (1986) Kotkan merihiekka 1985—virtaustutkimus. Merentutkimuslaitos, Sisäinen raportti 5/1986. [Kotka sea sand 1985—current measurements. Finnish Institute of Marine Research, Internal report 5/1986] 28:1–12 (in Finnish)
Alenius P, Myrberg K, Nekrasov A (1998) Physical oceanography of the Gulf of Finland: a review.
Boreal Environ Res 3:97–125
Alenius P, Nekrasov A, Myrberg K (2003) The baroclinic Rossby-radius in the Gulf of Finland.
Cont Shelf Res 23:563–573
Andrejev O, Myrberg K, Alenius P, Lundberg PA (2004a) Mean circulation and water exchange
in the Gulf of Finland—a study based on three-dimensional modelling. Boreal Environ Res
9:1–16
217
An adequate representation of such a complicated multi-layered circulation
needs refined and tailored schemes not only for mesoscale motions but also for
the description of vertical turbulence in the Gulf of Finland. The methods for its parameterization used in contemporary circulation models of the Baltic Sea are taken
from general ocean models and do not necessarily fit the specific conditions in the
gulf. Several studies have suggested that the improper replication of the vertical turbulence might be a major reason for the mismatch of the model results and measurements in the Baltic (Myrberg et al. 2010a). An improvement of this shortcoming has
a large potential for a more reliable replication of both the dynamical and statistical
features of current-driven transport of various pollutants and contaminants.
Finally, we would like to emphasize that the processes affecting the long-term
mean surface circulation and its modelled or observed outcome in the Gulf of Finland are essentially non-linear and exhibit a number of sophisticated feedbacks. For
example, the wind-independent baroclinic mean circulation and the mean winddriven circulation interact with each other in a highly non-linear manner and it is
virtually impossible to specify which one is more important. Moreover, the answer
to this question depends on the case studied and on the time scale under investigation. The circulation studies set extremely high demands for the modelling work and
measurement campaigns not only because of the small internal Rossby radius in this
basin but, perhaps more importantly, due to the above-mentioned complex dynamics that is not directly evident from simple scaling exercises. The role of the model
resolution becomes clearly evident in the following chapters that are dedicated to
detailed studies of circulation and associated transport and drift properties.
Acknowledgements This study was performed in the framework of the BalticWay project, which
was supported by the Estonian Science Foundation, the Academy of Finland and by funding from
the European Commission’s Seventh Framework Programme (FP7 2007–2013) under grant agreement No. 217246 made with the joint Baltic Sea research and development programme BONUS.
The research was partially supported by the Estonian Science Foundation (grant No. 9125), targeted financing by the Estonian Ministry of Education and Research (grant SF0140007s11), and by
the European Regional Development Fund via support to the Centre of Excellence for Non-linear
Studies CENS. The authors are particularly grateful to Dr. J. Laanemets and to an anonymous
reviewer for highlighting several gaps and misinterpretations in the original version of the chapter.
References
Alenius P (1986) Kotkan merihiekka 1985—virtaustutkimus. Merentutkimuslaitos, Sisäinen raportti 5/1986. [Kotka sea sand 1985—current measurements. Finnish Institute of Marine Research, Internal report 5/1986] 28:1–12 (in Finnish)
Alenius P, Myrberg K, Nekrasov A (1998) Physical oceanography of the Gulf of Finland: a review.
Boreal Environ Res 3:97–125
Alenius P, Nekrasov A, Myrberg K (2003) The baroclinic Rossby-radius in the Gulf of Finland.
Cont Shelf Res 23:563–573
Andrejev O, Myrberg K, Alenius P, Lundberg PA (2004a) Mean circulation and water exchange
in the Gulf of Finland—a study based on three-dimensional modelling. Boreal Environ Res
9:1–16