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Anatomizing one of the largest saltwater inflows into the B altic S ea in D ecember 2014
Author(s) -
Gräwe Ulf,
Naumann Michael,
Mohrholz Volker,
Burchard Hans
Publication year - 2015
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2015jc011269
Subject(s) - inflow , tracer , salinity , baroclinity , annual cycle , environmental science , oceanography , geology , climatology , physics , nuclear physics
Abstract In December 2014, an exceptional inflow event into the Baltic Sea was observed, a so‐called Major Baltic Inflow (MBI). Such inflow events are important for the deep water ventilation in the Baltic Sea and typically occur every 3–10 years. Based on first observational data sets, this inflow had been ranked as the third largest since 100 years. With the help of a multinested modeling system, reaching from the North Atlantic (8 km resolution) to the Western Baltic Sea (600 m resolution, which is baroclinic eddy resolving), this event is reproduced in detail. The model gave a slightly lower salt transport of 3.8 Gt, compared to the observational estimate of four Gt. Moreover, by using passive tracers to mark the different inflowing water masses, including an age tracer, the inflowing water masses could be tracked and their paths and timing through the different basins could be reproduced and investigated. The analysis is supported by the recently developed Total Exchange Flow (TEF) to quantify the volume transport in different salinity classes. To account for uncertainties in the modeled velocity and tracer fields, a Monte Carlo Analysis (MCA) is applied to correct possible biases and errors. With the help of the MCA, 95% confidence intervals are computed for the transport estimates. Based on the MCA, the “best guess” of the volume transport is 291.0 ± 13.65 km 3 and 3.89 ± 0.18 Gt for the total salt transport.