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Recent studies on the Adriatic long-term oceanographic changes Ivica Vilibić Institute of Oceanography and Fisheries, Split, Croatia,

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Presentation on theme: "Recent studies on the Adriatic long-term oceanographic changes Ivica Vilibić Institute of Oceanography and Fisheries, Split, Croatia,"— Presentation transcript:

1 Recent studies on the Adriatic long-term oceanographic changes Ivica Vilibić Institute of Oceanography and Fisheries, Split, Croatia, vilibic@izor.hr

2 Papers: Vilibić, I., Matijević, S., Šepić, J., Kušpilić, G., 2012. Changes in the Adriatic oceanographic properties induced by the Eastern Mediterranean Transient. Biogeosciences, 9, 2085-2097. Vilibić, I., Šepić, J., Proust, N., 2013. Weakening of thermohaline circulation in the Adriatic Sea. Climate Research, 55, 217–225. Vilibić, I., Pištalo, D., Šepić, J., 2015. Long-term variability and trends of relative geostrophic currents in the middle Adriatic. Continental Shelf Research, 93, 70-80. Vilibić, I., Čikeš Keč, V., Zorica, B., Šepić, J., Matijević, S., Džoić, T., 2015. Hydrographic conditions driving sardine and anchovy populations in a land-locked sea. Marine Mediterranean Science, in press, doi: 10.12681/mms.1120. Vilibić, I., Mihanović, H., Ivčević, A., Kušpilić, G., Milun, V., 2015. Mapping of oceanographic properties along a middle Adriatic transect by using Self- Organising Maps. Estuarine Coastal and Shelf Science, in press. Mihanović, H., Vilibić, I., Dunić, N., Šepić, J., 2015. Mapping of decadal middle Adriatic oceanographic variability and its relation to the BiOS regime. Journal of Geophysical Research, under review.

3 Palagruža Sill Data: - Palagruža transect - Stations P1 (528), P2 (529), P3 (216), P4 (206), P5 (199) – number of vertical profiles in brackets - 1952-2010 - temperature, salinity, DO, TIN, HPO 4 2-

4 Vilibić et al. (BG, 2012)EMT  A strong footprint of EMT in all physical and chemical parameters

5 Vilibić et al. (BG, 2012)  Different TIN/HPO4 ratio during the EMT period indicate different origin of the intermediate water masses in the Adriatic Sea

6 T, S,  t, DO trends 1952-2010 significant at 95% significant at 95% o insignificant ItalyCroatia Vilibić et al. (CR, 2013)  Trends in the last 60 years indicate a weakening of the Adriatic THC

7 Vilibić et al. (CSR, 2015) NEMOMED8 RegCM trends  RegCM do not reproduce weakening of the Adriatic THC

8 Vilibić et al. (MMS, 2015)  Fluctuations of sardine and anchovy parameters are dependant o n fluctuations of the Adriatic hydrography.

9 Mihanović et al. (JGR, 2015) SOM setup: batch training algorithm (efficient training)batch training algorithm (efficient training) a 4x3 SOM grid (good compromise between details and graphic presentation)a 4x3 SOM grid (good compromise between details and graphic presentation) rectangular lattice structure (preferable for small size SOMs)rectangular lattice structure (preferable for small size SOMs) linear initialization of unit weights (EOF decomposition and linear interpolation of the first two leading EOFs – saves time with complex data sets)linear initialization of unit weights (EOF decomposition and linear interpolation of the first two leading EOFs – saves time with complex data sets) “ep” neighborhood function (gives the least smoothing to the SOM units)“ep” neighborhood function (gives the least smoothing to the SOM units) The data: T, S, DO at the Palagruža Sill, 1952-2010 T, S, DO at the Palagruža Sill, 1952-2010 Application of a novel method, Self-Organizing Maps (SOM), to the Adriatic long-term thermohaline series. Motivation: To objectively map the characteristic thermohaline patterns over the Palagruža Sill.

10 Mihanović et al. (JGR, 2015) The data: T, S, DO at the Palagruža Sill, 1952-2010 T, S, DO at the Palagruža Sill, 1952-2010 Bad data example

11 Mihanović et al. (JGR, 2015)  Objectively extracted patterns at the transect  SOM patterns (BMUs) stand for different circulation modes of the Adriatic, reflecting in water mass and primary production dynamics

12 Mihanović et al. (JGR, 2015)  Changing the length of the dataset and the number of stations used does not change largely SOM patterns BIOS is the dominant generator of the Adriatic variability  BIOS is the dominant generator of the Adriatic variability All data, gaps 1975-2010, without P4 1994-2010, no gaps

13 Mihanović et al. (JGR, 2015)  SOM patterns of the Absolute Dynamic Topography (ADT) in northern Ionian Sea show a strong resemblance with T-S changes along the Palagruža Sill  Assymetric ADT patterns in the northern Ionian Sea  BiOS reversals may be rapid (within a year) or slow (2-3 years), resulting in a rapid or a slow changes in the Adriatic properties

14 Some SCOOL perpectives...Data: - There are other long-term stations which may be investigated for long-term changes  e.g. in coastal region coming from Pag-Konavle monitoring programme, D1200,... -... to be used for assessment of changes in eastern coastal area Research topics: - Connecting Adriatic changes to the Ionian circulation - Analysing climate hindcast and projections for the Adriatic decadal changes and processes (DWF, BiOS) - Constructing a simple BiOS-based index - Reconstructing oceanographic conditions from chronologies - Connecting chronologies with long-term data measurements


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