Present climate trends and variability in thermohaline properties of the northern Adriatic shelf

Abstract

Abstract. The paper documents seasonality, interannual-to-decadal variability, and trends in temperature, salinity, and density over a transect in the shallow northern Adriatic Sea (Mediterranean Sea) between 1979 and 2017. The amplitude of seasonality decreases with depth and is much larger in temperature and density than in salinity. Time series of temperature and salinity are correlated in the surface but not in the bottom layer. Trends in temperature are large (up to 0.6 ∘C over 10 years), significant through the area, and not sensitive to the sampling interval and time series length. In contrast, trends in salinity are largely small and insignificant and depend on the time series length. The warming of the area is more during spring and summer. Such large temperature trends and their spatial variability emphasize the importance of maintaining regular long-term observations for the proper estimation of thermohaline trends and their variability. This is particularly important in regions which are key for driving thermohaline circulation such as the northern Adriatic, with the potential to affect biogeochemical and ecological properties of the whole Adriatic Sea.

Temporal and Spatial Variability of the CO2 System in a Riverine Influenced Area of the Mediterranean Sea, the Northern Adriatic

“…A seawater temperature increase of +2.58 • C for the 2100 was also considered in our simulation, as projected by IPCC (2019) for global sea surface under RCP 8.5 scenario. The adopted trend implies a +0.03 • C yr −1 , which is intermediate between the NAd warming rate reported by Raicich and Colucci (2019) of 0.013 ± 0.005 • C yr −1 and that of 0.01-0.06 • C yr −1 reported by Vilibič et al (2019). The biogeochemical model for respiratory increases or photosynthetic decrease in CO 2 concentration is based on AOU calculations as described by Redfield et al (1963).…”

The Freshwater Balance of the Adriatic Sea: A Sensitivity Study

“…As shown in the following chapters, our initial simulation with the described implementation of river runoff (baseline simulation -UERRA-B) resulted in a negative trend in salinity (Figure 8) and DW formation (Figure 10) and failed to reproduce the PDA saw-tooth pattern in the SAP (Figure 11). This is contrary to observations (Mihanović et al, 2013;Querin et al, 2016;Vilibić et al, 2019) and in order to test the sensitivity of the model to river runoff, we decided to run the simulations with reduced discharge, higher salinity of rivers, or both (Table 1). The higher river salinity runs (S = 17 for Po and S = 15 for other rivers) were performed in accordance with Verri et al (2018) and Simoncelli et al (2011).…”

Performance of the Adriatic Sea and Coast (AdriSC) climate component – a COAWST V3.3-based one-way coupled atmosphere–ocean modelling suite: ocean results

“…Concerning the river forcing, 54 river flows in total (only 49 for the 1 km grid) are imposed over at least six grid points each (and 18 grid points for the Po river delta), with river mouths located along the coastline of the Italian peninsula, Sicily, Croatia, Slovenia, Albania, Montenegro, and Greece. The monthly climatology of the river flow is acquired from the RivDis database (Vörösmarty et al, 1996) and studies from Pano and Abdyli (2002), Malačič and Petelin (2009), Pano et al (2010), Janeković et al (2014), andLjubenkov (2015), whereas the river flow interannual variability is obtained from Ludwig et al (2009). Additionally, the river flows are linearly distributed between the first 20 sigma vertical levels -i.e.…”

“…This dataset combines 17 different experiments and/or scientific cruises: (1) Argo floats -ARGO (https://argo.ucsd.edu, last access: 20 September 2021), (2) ASCOP project Phase 2, Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), (3) Corfu System Project -CSP01 cruise (https://isramar.ocean.org.il/ PERSEUS_Data, last access: 20 September 2021), (4) Dynamics of the Adriatic in Real Time -DART_CTD (Martin et al, 2009;, (5) CTD observations, Institute of Oceanography and Fisheries (IOR) -IOR_Data_CTD, (6) Palagruža transect long-term observations -IOR_Pal_CTD, (7) Mediterranean Data Archaeology and Rescue project -MEDATLAS (http://www.ifremer. fr/medar/cdrom_database.htm, last access: 20 September 2021), (8) Northern Adriatic Experiment CTD observations -NAdEx_CTD (Vilibić et al, 2018), (9) Otranto Gap Experiment, SACLANT Undersea Research Centre -OTRANTO, (10) PALMAS, OGS, (11) PCO, Consiglio Nazionale delle Ricerche (CNR), Istituto di Biologia del Mare, Venice, (12) Physical Oceanography of the Eastern Mediterranean project, Hellenic National Oceanographic Data Centre (HCMR/HNODC) -POEM, (13) Programma di RIcerca e Sperimentazione del Mare Adriatico Phase 2 (chemical stations) hosted at OGS -PR2_UR, ( 14) Programma di RIcerca e Sperimentazione del Mare Adriatico Phase 1 hosted at OGS -PRISMA, (15) PRV, CNR, Istituto di Biologia del Mare, Venice, (16) Northern Adriatic long-term observations, Ru der Bošković institute -RB_NAd (Vilibić et al, 2019), and (17) SIRIAD cruise hosted at OGS -SIRIAD_15. This large dataset includes over 7000 locations in total and covers the Adriatic Sea almost entirely and partially the northern Ionian Sea.…”