1. Institute of Oceanography and Fisheries, Split, Croatia
The Adriatic-Ionian Bimodal Oscillating System (BIOS) and the Adriatic oceanography
Ivica Vilibić, Natalija Dunić, Hrvoje Mihanović, Jadranka Šepić
Institute of Oceanography and Fisheries, Split, Croatia
Outline:
Motivation
The BiOS and impact to the Adriatic ocean properties
Take-home messages
The work has been supported by the Croatian Science Foundation, project ADIOS (IP )

2. Motivation Once upon a time ...
... some unusual changes in salinity have been noticed in observations ...
Buljan, M. (1953). Fluctuations of salinity in the Adriatic, Izvještaj Republičke ribarstveno-biološke ekspedicije “Hvar” 1948–1949, Acta Adriat., 2, 1–64.
Zore-Armanda, M. (1963). Les masses d’eau de la mer Adriatique, Acta Adriat., 10, 5–88.
... following certain periodicity (ca. 10 years), influencing Adriatic water masses and more.

3. The BiOS
An explanation of the underlying physics has been offered half-century later ...
Gačić, M., Eusebi Borzelli, G. L., Civitarese, G., Cardin, V., and Yari, S. (2010). Can internal processes sustain reversals of the ocean upper circulation?, The Ionian Sea example, Geophys. Res. Lett., 37, L09608,
... boosting the research on this topic in the last decade.
... we show that surface flow in the northwestern Ionian co-varies with the density of water masses formed in the Southern Adriatic ...
The phenomenon has been named Adriatic-Ionian Bimodal Oscillating System (BiOS).

4. A rapid increase in salinity for ~0.3
The BiOS
The relevance of the BiOS to the Mediterranean dynamics is still work in progress, i.e. its interconnection with other basins, is it part of the greater oscillating system, quantification of processes that sustain oscillations (internal vs. wind dynamics, Adriatic vs. Aegean, ...) ...
Vilibić et al., BGS, 2012
What we know is that:
The BiOS is changing a lot the Adriatic thermohaline properties
A rapid increase in salinity for ~0.3
Janeković et al., JGR, 2014
observations
model
The salinity increase was an important preconditioning for the dense water formation event in 2012.

5. The BiOS
The BiOS-induced changes are altering (relatively) fast the Adriatic ocean properties.
BiOS index = SLHin-SLHout
Mihanović et al. (JGR, 2015)
Matić et al. (CSR, 2017)

6. The BiOS
BiOS-induced changes are affecting (almost) the whole Adriatic.
Areas where significant (95%) correlations between the BiOS index and an ocean variable has been documented
Significant correlations are present between bivalve G. pilosa bivalve and the BiOS index.
Peharda et al. (Sci Rep, 2018)

7. The BiOS
BiOS is influencing biogeochemistry, primary production, trophic chain, fisheries, ..., in the Adriatic Sea
Civitarese et al. (BGS, 2010)

8. The BiOS
... We found that pluriannual changes in the zooplankton community tracked the continuum of circulation regimes in the Northern Ionian Gyre (NIG). The occurrence of Atlantic/Western Mediterranean species coincided with anti-cyclonic circulation in the NIG, probably due to the advection of Modified Atlantic Water into the Adriatic, while the presence of Lessepsian species coincided with the cyclonic pattern, which governs the entry of Eastern Mediterranean waters ...
Batistić et al. (Clim Res, 2014)

9. The BiOS
Present ocean climate models are still far from a proper reproduction of BiOS ...
Dunić et al. (OM, under review)
... Overall, coupled models better reproduce the thermohaline properties and processes, in particular the Adriatic-Ionian Bimodal Oscillating System (BiOS) reversals and its decadal variability ...
More on ocean model performance in the Adriatic Sea tommorrow by Natalija Dunić

10. The BiOS
... so that new modelling system (WRF/ROMS) has been developed under the ADIOS project  the simulation is just under way.
ROMS SET-UP:
2 Grids: One-Way Nested
Outer Grid 3 Km: 266 x 361
Same domain than WRF inner
Inner Grid 1 Km: 676 x 730
35 vertical levels with bottom and surface refinements
Bulk Formulae
MPDATA advection
GLS mixing
Nudging of the climatology on the outer grid
WRF SET-UP:
2 Grids: Two-Way Nested
Outer Grid 15 Km: 140 x 140
Inner Grid 3 Km: 266 x 361
58 vertical levels with surface refinements
MYJ PBL scheme
Kain-Fritch CPS (only for outer)
Morrison MPS
Dudhia & RRTM short& long-wave radiation
Atm. GCM
WRF
SST
Post-Processing
ROMS
OSU Tidal Forcing
River
Forcing
Ocean GCM

11. Take-home messages
A small portion of the research relevant for BiOS is presented, we really acknowledge all the BiOSian people :)
BiOS is a dominant process for altering oceanographic, biogeochemical, biological and other properties in the Adriatic on a decadal scale
Path-to-go: Proper reproduction of the BiOS will allow for proper assessment of the BiOS and related changes in the future climate