Neural network approach to sea-level modeling case study of a storm surge in the gulf of trieste in early december 2008

Tide tables can be a useful tool for sea-level forecasting in many areas. Slovenian operational\ud service for hydrological forecasts at the Environmental Agency of the Republic of Slovenia\ud frequently deploys tide tables alongside least square harmonic analysis to predict maximum sea\ud levels in the Gulf of Trieste. Meteorological influences such as pressure gradient, wind stress and\ud induced basin eigenoscillations (seiches) along the main axis of the Adriatic basin have repeatedly\ud been proven as important factors influencing the sea level in the Gulf of Trieste. They are, however,\ud only indirectly included in the harmonic analysis which in itself requires a large number of\ud carefully tuned model parameters in order to make useful short-range forecasts. A number of recent\ud reports show that an artificial neural network (ANN) can greatly improve sea level forecasts,\ud providing we supply it with suitable input variables (ie. previous water levels, air pressure, wind\ud speed, wind direction, tide charts etc.) We report on an ANN-based analysis of the recent storm\ud surge and flooding events at the Slovenian coast in the beginning of December 2008. The ANN\ud model compares favourably with the currently used conventional forecasting methods.\u

Weibullova distribucija bure i juga na sjevernom Jadranu

Wind data measured at three off-shore stations in the northern part of the Adriatic Sea were considered: the Coastal oceanographic station Piran buoy (COSP), the PALOMA tower (the Gulf of Trieste) and the A. ALTA platform (Venice). Annual wind roses for all stations and additional seasonal wind roses for COSP are presented. The Weibull distribution function was applied to wind speed frequency distribution for winds from all directions and separately for bora and sirocco winds. Wind speed frequency distributions for bora winds measured at COSP and PALOMA are bimodal. One peak of this distribution of speeds belongs to nocturnal land breezes and another to bora winds. The peak separation method based on the difference in potential temperature of the atmospheric boundary layer (ABL) between two land stations (Udine and Zagreb) enabled the successful separation of the peaks of bora and land breeze winds. The frequency distribution of the wind speeds changed to the usual unimodal distribution when only those episodes were considered in which the potential temperature of ABL above Udine is higher than that above Zagreb.Obrađeni su podaci na tri morske postaje na sjevernom Jadranu: oceanografskoj plutači Obalne oceanografske postaje Piran (COSP), tornju Paloma u Tršćanskom zaljevu i na platformi A.ALTA ispred Venecije. Predstavljene su godišnje ruže vjetrova za sve tri postaje i dodatno sezonske ruže vjetrova za COSP. Weibullova distribucijska funkcija bila je primijenjena na razdiobu čestine brzine vjetra za vjetrove iz svih smjerova i posebno za buru i sirocco. Razdioba čestina brzine vjetra izmjerenog na COSP i PALOMA iz smjerova bure pokazala se kao bimodalna. Jedan vrh u toj distribuciji pripada dnevno-noćnoj cirkulaciji zraka, a drugi buri. Uspješna metoda separacije vrhova temelji se na razlici u potencijalnoj temperaturi zraka u atmosferskom graničnom sloju (AGS) iznad Udina i Zagreba. Razdioba čestina brzine vjetra postaje unimodalna kada se promatraju samo one epizode vjetra kad je potencijalna temperatura AGS iznad Udina viša od potencijalne temperature iznad Zagreba

Biogenic Amine Production during Spontaneous and Inoculated MLF of Zweigelt Wines

Biogenic amines are organic nitrogenous compounds produced in wines mainly during malolactic fermentation (MLF). Its presence is a health risk and it could negatively affect the wine quality. The objective of this work was to determine the biogenic amines content in Croatian Zweigelt wines produced with different MLF inoculation time. Biogenic amines were determined by liquid chromatographic method. Results showed significant influence of MLF on the concentrations of biogenic amines. Control wines had the lowest amount of total biogenic amines while wines in which MLF was conducted after alcoholic fermentation had significantly the highest concentrations of total biogenic amines. Between them histamine was the most abundant amine ranging from 1.14 mg/L in control wines up to 2.94 mg/L in wines that undergo MLF after alcoholic fermentation. It can be concluded that MLF process and time of inoculation can significantly influence the formation of biogenic amines. These results suggest that co-inoculation using Oenoccocus oeni commercial strain Uvaferm ß is a worthwhile alternative compared to traditional post AF inoculation for Zweigelt winemaking

Coastal Sea Level Monitoring in the Mediterranean and Black Seas

Spanning over a century, a traditional way to monitor sea level variability by tide gauges is – in combination with modern observational techniques like satellite altimetry – an inevitable ingredient in sea level studies over the climate scales and in coastal seas. The development of the instrumentation, remote data acquisition, processing and archiving in last decades allowed for extending the applications towards a variety of users and coastal hazard managers. The Mediterranean and Black50 seas are an example for such a transition – while having a long tradition for sea level observations with several records spanning over a century, the number of modern tide gauge stations are growing rapidly, with data available both in real-time and as a research product at different time resolutions. As no comprehensive survey of the tide gauge networks has been carried out recently in these basins, the aim of this paper is to map the existing coastal sea level monitoring infrastructures and the respective data availability. The survey encompasses description of major monitoring networks in the Mediterranean and Black55 seas and their characteristics, including the type of sea level sensors, measuring resolutions, data availability and existence of ancillary measurements, altogether collecting information about 236 presently operational tide gauge stations. The availability of the Mediterranean and Black seas sea level data in the global and European sea level repositories has been also screened and classified following their sampling interval and level of quality-check, pointing to the necessity of harmonization of the data available with different metadata and series at different repositories. Finally, an assessment of the networks’ capabilities60 for their usage in different sea level applications has been done, with recommendations that might mitigate the bottlenecks and assure further development of the networks in a coordinated way, being that more necessary in the era of the human-induced climate changes and the sea level ris

Neural network approach to sea-level modeling case study of a storm surge in the gulf of trieste in early december 2008

Na mnogih območjih so tablice plimovanja priročno orodje za napovedovanje morskega vodostaja. Sektor za hidrološke prognoze Agencije RS za okolje za napovedovanje morskega vodostaja v Tržaškem zalivu pogosto uporablja tablice plimovanja skupaj s harmonično analizo. Meteorološki vplivi, kot so gradient zračnega tlaka, veter in lastno nihanje morja vzdolž glavne osi Jadrana, so se mnogokrat izkazali kot pomembni dejavniki, ki vplivajo na višino vodostaja v Tržaškem zalivu. Ti dejavniki so v harmonične analize vključeni le posredno. Poleg tega za uporabne kratkoročne prognoze s pomočjo harmonične analize potrebujemo veliko število natančno umerjenih modelskih parametrov. Novejše raziskave so pokazale, da lahko uporaba umetnih nevronskih mrež bistveno izboljša napovedovanje vodostajev, če le vnesemo ustrezne vhodne spremenljivke (npr. predhodni vodostaj, zračni tlak, hitrost in smer vetra, tablice plimovanja itd.) Na dogodku neurnega vala (ang. storm surge) in poplavljanja morja na slovenski obali v začetku decembra 2008 smo izdelali analizo s pomočjo umetne nevronske mreže. Rezultati uporabe nevronskih mrež so dobro primerljivi s trenutno uporabljanimi konvencionalnimi metodami napovedovanja višine morskih gladin.Tide tables can be a useful tool for sea-level forecasting in many areas. Slovenian operational service for hydrological forecasts at the Environmental Agency of the Republic of Slovenia frequently deploys tide tables alongside least square harmonic analysis to predict maximum sea levels in the Gulf of Trieste. Meteorological influences such as pressure gradient, wind stress and induced basin eigenoscillations (seiches) along the main axis of the Adriatic basin have repeatedly been proven as important factors influencing the sea level in the Gulf of Trieste. They are, however, only indirectly included in the harmonic analysis which in itself requires a large number of carefully tuned model parameters in order to make useful short-range forecasts. A number of recent reports show that an artificial neural network (ANN) can greatly improve sea level forecasts, providing we supply it with suitable input variables (ie. previous water levels, air pressure, wind speed, wind direction, tide charts etc.) We report on an ANN-based analysis of the recent storm surge and flooding events at the Slovenian coast in the beginning of December 2008. The ANN model compares favourably with the currently used conventional forecasting methods

Numerical models for determining sea state in the Adriatic Sea

Numerični modeli za določanje stanja morja v Jadranskem morj