1. Turbulence observations in the Gulf of Trieste under moderate wind forcing and different water column stratificationFrancesco Marcello Falcieri, Lakshmi Kantha, Alvise Benetazzo, Andrea Bergamasco, Davide Bonaldo, Francesco Barbariol, Vlado Malačič, Mauro Sclavo, Sandro Carniel, 2016, izvirni znanstveni članek Povzetek: The oceanographic campaign CARPET2014 (Characterizing Adriatic Region Preconditionig EvenTs), (30 January–4 February 2014) collected the very first turbulence data in the Gulf of Trieste (northern Adriatic Sea) under moderate wind (average wind speed 10 m s−1) and heat flux (net negative heat flux ranging from 150 to 400 W m−2). Observations consisted of 38 CTD (Conductivity, Temperature, Depth) casts and 478 microstructure profiles (grouped into 145 ensembles) with three sets of yoyo casts, each lasting for about 12 consecutive hours. Averaging closely repeated casts, such as the ensembles, can lead to a smearing effect when in the presence of a vertical density structure with strong interfaces that can move up or down between subsequent casts under the influence of tides and internal waves. In order to minimize the smearing effect of such displacements on mean quantities, we developed an algorithm to realign successive microstructure profiles to produce sharper and more meaningful mean profiles of measured turbulence parameters.
During the campaign, the water column in the gulf evolved from well-mixed to stratified conditions due to Adriatic waters intruding at the bottom along the gulf's south-eastern coast. We show that during the warm and relatively dry winter, the water column in the Gulf of Trieste, even under moderate wind forcing, was not completely mixed due to the influence of bottom waters intruding from the open sea. Inside the gulf, two types of water intrusions were found during yoyo casts: one coming from the northern coast of the Adriatic Sea (i.e. cooler, fresher and more turbid) and one coming from the open sea in front of the Po Delta (i.e. warmer, saltier and less turbid). The two intrusions had different impacts on turbulence kinetic energy dissipation rate profiles. The former, with high turbidity, acted as a barrier to wind-driven turbulence, while the latter, with low sediment concentrations and a smaller vertical density gradient, was not able to suppress downward penetration of turbulence from the surface.
Ključne besede: hydrology, oceanographic data, numerical modelling, wind forcing, turbulence
Objavljeno v DiRROS: 01.08.2024; Ogledov: 111; Prenosov: 130
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2. Modeling the ocean and atmosphere during an extreme bora event in northern Adriatic using one-way and two-way atmosphere-ocean couplingMatjaž Ličer, Peter Smerkol, Anja Fettich, Michalis Ravdas, Alexandros Papapostolou, Anneta Mantziafou, Benedikt Strajnar, Jure Cedilnik, Maja Jeromel, Jure Jerman, Sašo Petan, Vlado Malačič, Sarantis Sofianos, 2016, izvirni znanstveni članek Povzetek: We have studied the performances of (a) a two-way coupled atmosphere%ocean modeling system and (b) one-way coupled ocean model (forced by the atmosphere model), as compared to the available in situ measurements during and after a strong Adriatic bora wind event in February 2012, which led to extreme air%sea interactions. The simulations span the period between January and March 2012. The models used were ALADIN (Aire Limitée Adaptation dynamique Développement InterNational) (4.4 km resolution) on the atmosphere side and an Adriatic setup of Princeton ocean model (POM) (1%=30%1%=30 angular resolution) on the ocean side. The atmosphere%ocean coupling was implemented using the OASIS3-MCT model coupling toolkit. Two-way coupling ocean feedback to the atmosphere is limited to sea surface temperature. We have compared modeled atmosphere%ocean fluxes and sea temperatures from both setups to platform and CTD (conductivity, temperature, and depth) measurements from three locations in the northern Adriatic.We present objective verification of 2m atmosphere temperature forecasts using mean bias and standard deviation of errors scores from 23 meteorological stations in the eastern part of Italy. We show that turbulent fluxes from both setups differ up to 20° during the bora but not significantly before and after the event. When compared to observations, two-way coupling ocean temperatures exhibit a 4 times lower root mean square errors (RMSE) than those from one-way coupled system. Two-way coupling improves sensible heat fluxes at all stations but does not improve latent heat loss. The spatial average of the two-way coupled atmosphere component is up to 0.3 °C colder than the one-way coupled setup, which is an improvement for prognostic lead times up to 20 h. Daily spatial average of the standard deviation of air temperature errors shows 0.15 °C improvement in the case of coupled system compared to the uncoupled. Coupled and uncoupled circulations in the northern Adriatic are predominantly wind-driven and show no significant mesoscale differences.
Ključne besede: sea, marine water, numerical modeling, physical oceanography, dense water, bora wind, Adriatic sea, Mediterranean sea, Adriatic shelf
Objavljeno v DiRROS: 26.07.2024; Ogledov: 112; Prenosov: 91
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3. Multi-platform, high-resolution study of a complex coastal system : the TOSCA experiment in the Gulf of TriesteStefano Querin, Simone Cosoli, Riccardo Gerin, Célia Laurent, Vlado Malačič, Neva Pristov, Pierre-Marie Poulain, 2021, izvirni znanstveni članek Povzetek: Abstract
Although small in size, the Gulf of Trieste (GoT), a marginal coastal basin in the northern Adriatic Sea, is characterized by very complex dynamics and strong variability of its oceanographic conditions. In April–May 2012, a persistent, large-scale anticyclonic eddy was observed in the GoT. This event was captured by both High Frequency Radar (HFR) and Lagrangian drifter observations collected within the European MED TOSCA (Tracking Oil Spill and Coastal Awareness) project. The complexity of the system and the variety of forcing factors constitute major challenges from a numerical modeling perspective when it comes to simulating the observed features. In this study, we implemented a high-resolution hydrodynamic model in an attempt to reproduce and analyze the observed basin-wide eddy structure and determine its drivers. We adopted the Massachusetts Institute of Technology General Circulation Model (MITgcm), tailored for the GoT, nested into a large-scale simulation of the Adriatic Sea and driven by a tidal model, measured river freshwater discharge data and surface atmospheric forcing. Numerical results were qualitatively and quantitatively evaluated against HFR surface current maps, Lagrangian drifter trajectories and thermohaline data, showing good skills in reproducing the general circulation, but failing in accurately tracking the drifters. Model sensitivity to different forcing factors (wind, river and tides) was also assessed.
Ključne besede: Adriatic Sea, surface circulation, HF coastal radars, Lagrangian drifters, wind-driven currents, ocean circulation models
Objavljeno v DiRROS: 19.07.2024; Ogledov: 98; Prenosov: 87
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4. Addendum to Diercks et al., 2021: A model for the formation of the Pradol (Pradolino) dry valley in W Slovenia and NE ItalyManuel Diercks, Christoph Grützner, Marko Vrabec, Kamil Ustaszewski, 2022, pregledni znanstveni članek Povzetek: In our paper Diercks et al. (2021) we presented geomorphological data and field observations from W Slovenia and NE Italy to develop a model for the formation of the Pradolino (slov. Pradol) dry valley. After publication we were kindly pointed to existing studies on the area that we were unaware of. To fill that gap and to properly credit previous work, in this addendum we summarise the research history on the study area and briefly compare earlier views with our model.
Ključne besede: wind gap, LGM, erosion, bedrock incision, Pradol
Objavljeno v DiRROS: 27.07.2022; Ogledov: 978; Prenosov: 290
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5. Windthrow factors - a case study on PokljukaNikica Ogris, Sašo Džeroski, Maja Jurc, 2004, izvirni znanstveni članek Povzetek: This paper presents a case study in windthrow. The case study area was 1.7 ha of two forest gaps on the Pokljuka plateau, Slovenia, where strong wind had blown down 44 trees. An additional 44 standing trees closest to the fallen trees were used as a control group for comparative purposes. The following variables were measured for fallen trees: breast diameter, height, crown diameter and height as well, the number and diameter of roots, the volume of the root system, and root rot. Standing trees were measured for breast diameter, height, crown diameter and height, and the number and diameter of roots. The data were analysed using the machine learning methods in the Weka computer program. The most important factors of windthrow in the case study area were: storm wind (speed above 17 m/s), wet shallow soil, and the edges ofthe forest gaps. The results of the case study show that breast diameter, tree height and the presence of root rot can be classified as windthrow factors.
Ključne besede: wind, windthrow, root rot, factors of windthrow
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4403; Prenosov: 1931
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6. Razvoj inicialne faze na vetrolomni površini v pragozdnem ostanku Ravna goraAleksander Marinšek, Jurij Diaci, 2004, izvirni znanstveni članek Povzetek: Zaradi vetroloma je leta 1983 v pragozdnem ostanku Ravna gora na Gorjancih na bukovem rastišču (Cardamini savensi-Fagetum) nastala 5,17 ha velika vrzel. Dejstvo, da je izsledkov o pomlajevanju po velikopovršinskih motnjah v pragozdovih malo, nas je vodilo k temu, da smo leta 2000 analizirali stanje indinamiko pomlajevanja vrzeli. Na treh različnih delih vrzeli smo postavili 15 raziskovalnih ploskev z dimenzijami 15 x 15 metrov, znotraj katerih smo analizirali zmes, razrast dreves, sestojno stanje po IUFRO klasifikaciji, pomladek in grobe lesne ostanke. Posebej nas je zanimalo razmerje med bukvijo (Fagus sylvatica L.) in gorskim javorjem (Acer pseudoplatanus L.). Slednjega je največ na sredini vrzeli. Pod sestojem, ki je zapolnil vrzel, je razvit pomladek bukve in javorja, ki je najgostejši na spodnjem (severnem) delu vrzeli. V pomladku prevladuje bukev. Ugotovili smo, da so bile razmere, ki so se izoblikovale po vetrolomu, bistveno drugačne od tipičnega goloseka. Predstavili smo tudi uporabne izsledke za gospodarjenje v gozdovih na podobnihrastiščih.Special attention is given to the gap, which was created in the virgin forest remnant Ravna gora in 1983 by wind throw. The gap in the optimal phase of almost pure beech and on beech site (Cardamini savensi-Fagetum) was 5.17 ha large. In 2000, owing to a lack of investigations in such conditions, we started to research the development patterns of natural regeneration within the gap. 15 sample plots (15 x 15 m) in three different positions within the gap were established. We analysed tree species mixture, architecture, stand structure according to IUFRO classification, advanced regeneration density andcoarse woody debris.The reserach concentrated in particular on the variability of beech (Fagus sylvatica L.) and sycamore (Acer pseudoplatanus L.) mixture in regard to theposition within the gap. It was found out that sycamore was more abundant than beech in the center of the gap. The advanced regeneration density of beech was much higher than sycamore's, and both species were more abundant in the northern part of the gap. The results suggest that the ecological conditions after the wind throw were different when compared to a clear-cut area of similar size. Useful results for managed forests on similar sites are also presented.
Ključne besede: pragozd, Ravna gora, vrzel, mladje, vetrolom, naravna obnova, Fagus sylvatica, Acer pseudoplatanus, virgin forest, gap, wind throw, natural regeneration
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4861; Prenosov: 2149
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