Vpliv povprečevanja vetrana hidrodinamiko Sredozemskega morja

Povzetek

Ključne besede

Podatki

Jezik:	Slovenski jezik
Leto izida:	2010
Izvor:	Ljubljana
Tipologija:	2.11 - Diplomsko delo
Organizacija:	UL FGG - Fakulteta za gradbeništvo in geodezijo
Založnik:	[A. Verdev]
UDK:	532.5:551.311:551.5(262)(043.2)
COBISS:	5177697
Št. ogledov:	2857
Št. prenosov:	464
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarni naslov:	Impact of wind averaging on hydrodynamics of the Mediterranean sea
Sekundarni povzetek:	Large quantity of quality input data is needed in order to simulate circulation with the model PCFLOW3D. The wind fields needed for such simulations are usually space and/or time averaged, particularly in larger domains such as the Mediterranean Sea. In such areas, more adequate input data is not possible to gather solely from measurements. European meteorological services provide daily or weekly forecasts in different resolutions. These forecasts can be used as the best approximation of the real wind-fields in various domains. The results of meteorological models are mostly compressed in GRIB format files. In this study data from the forecasts provided by the University of Athens (IASA) were used. Hourly forecasts for the entire Mediterranean Sea are available in resolution 0,1 x 0,1 degree. Using a newly developed interface, the GRIB data were transformed to ASCII format and further to database. Averaging over different time intervals followed by statistical analyses was performed on these data. The analyses showed relatively large discrepancies and loss of wind energy, both increasing with the length of the averaging interval. From the same high resolution wind fields input data for the model PCFLOW3D was prepared and the same statistic analyses were concluded. The comparison of discrepancies in wind force values confirmed credibility of the input data for modelling. Hydrodynamic simulations of the Mediterranean Sea were performed using wind fields averaged over different time intervals. These simulations however showed very small discrepancies between the circulation patterns. It can be concluded that the impact of wind averaging interval on the circulation of the Mediterranean Sea becomes significant only on a scale larger of a month (using such rough resolution). On the other hand, the Mediterranean Sea is too large for simulations in significantly finer resolution (e.g. 0.1 x 0.1 deg. and surface layer thickness of an order of 1 m) with such detailed wind data in reasonable computational time. The impact of wind averaging interval can be clearly seen only in smaller (semi-closed) and shallower areas, mainly near the coastline.
Sekundarne ključne besede:	graduation thesis;three-dimensional model;mathematical model;hydrodynamic model;meteorological model;Mediterranean sea;GRIB;
Vrsta datoteke:	application/pdf
Vrsta dela (COBISS):	Diplomsko delo
Komentar na gradivo:	Univ. Ljubljana, Fakulteta za gradbeništvo in geodezijo, Univerzitetni študij gradbeništva, Hidrotehnična smer
Strani:	XVI, 83 f.
Vrsta dela (ePrints):	thesis
Naslov (ePrints):	Impact of wind averaging on hydrodynamics of the Mediterranean Sea
Ključne besede (ePrints):	tridimenzionalni model;matematični model;hidrodinamični model;meteorološki model;Sredozemsko morje;GRIB
Ključne besede (ePrints, sekundarni jezik):	three-dimensional model;mathematical model;hydrodynamic model;meteorological model;Mediterranean Sea;GRIB
Povzetek (ePrints):	Za račune cirkulacije z modelom PCFLOW3D potrebujemo veliko količino kvalitetnih vhodnih podatkov. Podatki o vetru so predvsem pri simulacijah na večjih območjih, kot je npr. Sredozemsko morje, običajno časovno ali krajevno povprečni. Na tako velikih območjih ni mogoče pridobiti ustreznejših vhodnih podatkov samo iz meritev. Meteorološke službe v Evropi izdajajo dnevno ali tedensko napoved v različnih resolucijah, ki jo je mogoče uporabiti kot najboljši približek dejanske vetrovne slike na območjih različnih velikosti. Rezultati meteoroloških modelov so večinoma zapisani v stisnjenih datotekah formata GRIB. V nalogi so bili uporabljeni podatki urnih napovedi, ki jih z resolucijo 0,1 x 0,1 stopinje za celotno območje Sredozemlja izdaja Univerza v Atenah (IASA). Podatke tipa GRIB smo s pomočjo izdelanega vmesnika pretvorili v ASCII obliko in jih zapisali v bazo podatkov, nato pa podatke povprečili prek različnih časovnih intervalov in jih statistično obdelali. Analiza je pokazala razmeroma velika odstopanja in izgubo vetrne energije, ki narašča z večanjem intervala povprečevanja. Iz istih podatkov v visoki resoluciji, smo pripravili vhodne podatke za model PCFLOW3D in na njih opravili enako statistično analizo. Na podlagi primerjave odstopanja srednjih vrednosti smo ugotovili, da so podatki primerni za uporabo v modelu PCFLOW3D. S podatki povprečenimi v različnih časovnih intervalih smo izvedli simulacije cirkulacije Sredozemskega morja. Odstopanja rezultatov z upoštevanjem vetra povprečenega v različnih časovnih intervalih so bila zelo majhna. Iz študije lahko sklepamo, da je za sliko cirkulacije Sredozemlja ob simulacijah s tako grobo resolucijo vpliv časovno spremenljivega vetra na manj kot mesečni ravni nepomemben. Obravnavano območje je preveliko, da bi ga bilo mogoče modelirati v bistveno manjši resoluciji (npr. 0,1 x 0,1 stopinje in debelina površinskega sloja reda velikosti 1 m) s tako detajlnimi podatki o vetru v razumno dolgem simulacijskem času. Na manjših (polzaprtih) in plitvejših območjih (predvsem ob obali) pa se vpliv krajevno in časovno spremenljivega vetra na cirkulacijo jasno pokaže.
Povzetek (ePrints, sekundarni jezik):	Large quantity of quality input data is needed in order to simulate circulation with the model PCFLOW3D. The wind fields needed for such simulations are usually space and/or time averaged, particularly in larger domains such as the Mediterranean Sea. In such areas, more adequate input data is not possible to gather solely from measurements. European meteorological services provide daily or weekly forecasts in different resolutions. These forecasts can be used as the best approximation of the real wind-fields in various domains. The results of meteorological models are mostly compressed in GRIB format files. In this study data from the forecasts provided by the University of Athens (IASA) were used. Hourly forecasts for the entire Mediterranean Sea are available in resolution 0,1 x 0,1 degree. Using a newly developed interface, the GRIB data were transformed to ASCII format and further to database. Averaging over different time intervals followed by statistical analyses was performed on these data. The analyses showed relatively large discrepancies and loss of wind energy, both increasing with the length of the averaging interval. From the same high resolution wind fields input data for the model PCFLOW3D was prepared and the same statistic analyses were concluded. The comparison of discrepancies in wind force values confirmed credibility of the input data for modelling. Hydrodynamic simulations of the Mediterranean Sea were performed using wind fields averaged over different time intervals. These simulations however showed very small discrepancies between the circulation patterns. It can be concluded that the impact of wind averaging interval on the circulation of the Mediterranean Sea becomes significant only on a scale larger of a month (using such rough resolution). On the other hand, the Mediterranean Sea is too large for simulations in significantly finer resolution (e.g. 0.1 x 0.1 deg. and surface layer thickness of an order of 1 m) with such detailed wind data in reasonable computational time. The impact of wind averaging interval can be clearly seen only in smaller (semi-closed) and shallower areas, mainly near the coastline.
Ključne besede (ePrints, sekundarni jezik):	three-dimensional model;mathematical model;hydrodynamic model;meteorological model;Mediterranean Sea;GRIB
ID:	8309665