Year: 2024
Type: article
Abstract: For the Gulf of Finland, we carried out the EOF (empirical orthogonal functions) analysis of hourly forecasts from the Baltic Sea operational HIROMB-SMHI model for the period 2006-2008.It is possible to distinguish two regions with a specific regime of circulation variability.The western region behaves like a wide channel.Dominant EOF modes at different sections have similar patterns and their time-dependent amplitudes are well correlated.A prevailing mode of currents (23%-42% of the variance) is barotropic (unidirectional over the whole section) and its oscillation (spectral peak at 24 h) is related to the water storage variation of the Gulf.A two-layer flow pattern (surface Ekman transport with deeper compensation flow, 19%-22%) reveals both inertial and lower frequencies.Highest outflow of surface waters occurs during north-easterly winds.The eastern wider region has more complex flow dynamics and only patterns that are nearly uniform over the whole Gulf were detected here.On the sea surface, quasi-uniform drift currents are deflected on the average by 40° to the right from the wind direction and they cover 60% of the circulation variance.Sea level variability is heavily (98%) dominated by nearly uniform changes which are caused by the water storage variations of the Gulf.Sea level gradients contain the main axis (23%) and transverse (17%) components, forced by winds of the same direction.The flows below the surface are decomposed also into the main axis (24%-40%) and transverse (13%-16%) components that are correlated with the sea level gradients according to the geostrophic relations.
Source: Työväentutkimus Vuosikirja
DOI: 10.60910/15ke-rv60
Authors: Elken, Jüri, Nõmm, Marden, Lagemaa, Priidik
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
Funder: Eesti Teadusfondi
OpenAlex ID: W2894616541