1,721,052 research outputs found
Bonacci (Ognjen), 1987. — Karst hydrology, with special reference to the Dinaric karst
No full textGuilcher André. Bonacci (Ognjen), 1987. — Karst hydrology, with special reference to the Dinaric karst. In: Norois, n°145, Janvier-Mars 1990. Iles et sociétés insulaires. pp. 103-104
Application of techologies based on hydroacoustics, radar and pressure sensors in monitoring and analysis of water movement in karst : doctoral thesis
Full text linkZbog svoje iznimne ranjivosti, krški vodonosnik predstavlja izazov u pogledu zaštite, praćenja, održavanja kvalitete vode i eksploatacije. Hidrološki i hidrogeološki procesi kod krša su ekstremno nepredvidivi zbog anizotropnosti i heterogenosti samog vodonosnika. Procjena regionalne hidrodinamike podzemlja krških terena je često iznimno teška zadaća. Svaki krški vodonosnik ima specifična hidrogeološkai hidrološka svojstva što u konačnici zahtjeva regionalna mjerenja i inkorporaciju prikupljenih saznanja u daljnje modeliranje i upravljanje istim. Razvoj novih tehnologija mjerenja i praćenja vodonosnika u poljima hidroakustike, radara, mjernih senzora i računalne tehnologije, nastaje potreba za implementacijom iste i generiranja novih protokola i metoda mjerenja. Nadalje, nova tehnologija pruža daleko veće mogućnosti te samim time otvara prostor za nove spoznaje vezane za krški vodonosnik te preispituje stare. Vremenska i prostorna rezolucija mjerenja se povećavaju, a računalna tehnologija nudi izvrstan alat za analizu i uspostavljanje modela procesa u prirodi koji vode do boljeg razumijevanja. Glavni pokretač pri izradi ovog rada je stjecanje novih i poboljšavanje starih saznanja o dinamici vode unutar krškog vodonosnika i na površini proučavajući podzemnu dinamiku vode u špiljama i jamama kao i površinsku na primjeru krških jezera i otvorenih vodotoka. Nove spoznaje vezane za prirodu kretanja vode u krškom terenu rezultiraju upravo eksperimentalnim pristupom i mjerenju različitih hidroloških epizoda unutar izrazito heterogenog sustava. U ovom radu se prikazuju kontinuirana hidrološka mjerenja izvedena u dubokoj krškoj jami te se uspostavljaju modeli mjerenih parametara. Nadalje, primjenjuje se probabilistički koncept mjerenja protoka na otvorenom vodotoku kod nepravilnih profila te se pritom uvode novi protokoli mjerenja. Po prvi puta detaljno su snimljena morfometrijska mjerenja Crvenog i Modrog jezera kod Imotskog s najnovijim dostupnim tehnologijama te kontinuirana hidrološka mjerenja Modrog jezera. Prezentiran je također i uspostavljeni hidrološki model za Modro jezero.Because of its extreme vulnerability karst aquifer is a challenge in terms of protection, monitoring, maintenance of water quality and exploitation. Hydrologic and hydrogeological processes in karst are extremely unpredictable because of anisotropy and heterogeneity of the aquifer. Assessment of regional hydrodynamics of underground karst terrain is often extremely difficult task. Each karst aquifer has specific hydrogeological and hydrologic properties, which ultimately require a regional measurement and incorporation of gathered data in further modelling and management. The development of new technology based measurement and monitoring of aquifers in the fields of hydro acoustics, radar measurement, sensors and computer technology creates a need to implement theexisting and generate the new protocols and methods of measurement. Furthermore, the new technology provides far greater opportunities and thus they open up new insights related to karst aquifer and revise the old ones. Temporal and spatial resolution of measurements increase whereas computer technology offers an excellent tool for analyzing and establishing a models of processes in nature that lead to a better understanding. The main motivation for this dissertation is the gaining of new knowledge in the dynamics of water within the karstaquifer and on the karst surface, as well as improvement and validation of old findings by studying the dynamics of underground water in the caves and in the case of surface karst lakesand open streams taking into account. Experimental approach and measurement of hydrological episodes within a highly heterogeneous system result with a new insight in the nature of water movement in the karst terrain. The continuous hydrological measurements in a deep karst cave and established models of the measured parameters are presented in this work. Furthermore, the probabilistic concept of discharge measurement in open water course with irregular profile was carried out which led to introduction of new measurement protocols. For the first time, the detailed morphometric measurements using available emerging technologies were conducted for Red Lake and Blue Lake near Imotski. Continuous hydrological measurements of Blue Lake resulted with a hydrological model which is also presented in this work
Identification of hidrological regimes in karst with conceptual and parametric models : doctoral thesis
Full text linkKarakteristike vodne bilance krškog vodonosnika čine različiti oblici tečenja vode na koju osim količine padalina utječu kompleksni heterogeni hidrogeološki procesi koji su najčešće direktno ne mjerljivi. Osim problema mjerenja, identifikacija hidroloških režima postaje teža ukoliko su i postojeća mjerenja oskudna i ne kontinuirana. Unatoč konstantnoj nesigurnosti u predviđanju prirodnih pojava, matematički je moguće modelirati procjenitelje koji analiziraju postojeće stanje sustava te dati naznaku trenda njihovih glavnih obilježja. Studije odnosa padalina i oborina tzv. rainfall-runoff (RR) modeli dolaze sve više do značaja zbog boljih mogućnosti implementacije postojećih podataka. RR modeli čine skup različitih matematičkih principa koji u sumi pokušavaju opisati karakteristike riječnog bazena sa određenim pretpostavkama temeljenima na procesnim parametrima kao što su oblik krivulje recesije, površina otjecanja, odnos brzog i sporog otjecanja, količina vode u tlu i slično. Ukoliko se parametri uspješno kalibriraju i testiraju mogu dobiti traženi smisao u vidu opisivanja regionalnih karakteristika područja. Kalibrirani model predstavlja ponašanje hidrološkog sistema pod uvjetima koji su utvrđeni u bazi podataka. Uzimajući ove pretpostavke u obzir, modeliranje kompleksnih krških vodonosnika zahtjeva konceptualni pristup i pristup računalnog učenja. Trenutno dostupna računalna tehnologija postaje sve korisniji alat u analizi procesa za koje je znanje relativno ograničeno jer prije svega značajno smanjuje procesorsko vrijeme računanja te je fleksibilnija i razumljivija krajnjem korisniku. Cilj korištenih modela u ovom radu je pronalaženje ključnih parametara koje određeni model koristiti za uspješno opisivanje promatranih pojava. Iskorištena je mogućnost konceptualnog modela da se jednostavnim transfer funkcijama simuliraju različiti režimi otjecanja u koje je ugrađena informacija o načinu formiranja krivulje recesije kao i stanje količine vode u tlu. S druge strane parametarski model ne daje uvid u načina transformacije podataka, traži sustavan pristup određivanju njegove strukture ali daje veću točnost u usporedbi sa konceptualnim modelima. Implementacija korisnih saznanja o dinamici kretanja vode pomoću oba modela stvorila je bolju sliku dosad hidrološki neistraženog područja u kršu.Water balance characteristic of karst aquifer consist of different water regime flows influenced not only with amount of precipitation but especially with heterogenic and hydrogeological processes which can’t be directly measured. Aside from measurement problems, identification of hydrological regime becomes more difficult if the available data is scarce and discontinuous. Although constant uncertainty is always present in predicting natural phenomena, it is possible to model estimators which can be used to analyse current state of the system and give indication trends of their main features. Relations between rainfall and runoff, the RR model, are becoming more prominent because of their capabilities to implement noisy data. RR model represents an assembly of different mathematical principles trying to describe functioning of river catchment. RR models use certain assumptions about shapes of recession curve, catchment area, base flow-quick flow ratio, soilmoisture content and so on, to determine key parameters of the water circulation process. If the parameters are successfully calibrated and tested, they can be used as new insight to the properties of regional karst. Then, calibrated model represents hydrological behaviour under conditions determined in available database. Simulation of complex karst aquifer requires conceptual and computational learning approach. Current state of computer technology is becoming ever more useful in analysing processes of limited knowledge especially for the fact that computational time is becoming shorter and available software is more flexible and understandable to end user. Aim of proposed models is defining key factors for successful representation of observed runoff. Conceptual model combines transfer function and imbeds these key factors. Parametric model uses transformation which is not transparent but gives better approximation of cost function. Systematic approach to architectural design of parametric model overcomes these problems. Implementation of new findings from both models gives better hydrological understanding of investigated case study in karst
Ground water behaviour in karst: example of the Ombla Spring (Croatia)
No full textThe hydro-electric power plant (HEPP) which will exclusively use water from a karst underground storage basin will be built in the vicinity of the abundant karst spring Ombla in Croatia. This paper presents the results obtained by hydrogeologic, hydrologic and hydraulic investigations related to the principles of ground water circulation in the karst. The analyses included the determination of the effective porosity ne of the karst aquifer and the definition of the volume of large conduits and small fractures in the karst which form the aquifer volume. The position and dimensions of large karst conduits have also been defined. It was established that in three small springs, Zaton, Zavrelje and Slavljan, water overflows from the Ombla Spring in periods of high ground water levels. It was also discovered that at certain periods the Dupuit expression for steady-state flow in an unconfined aquifer can be used. In accordance with this, it was possible to determine the values of hydraulic conductivity, K (in m s−1), for the Ombla aquifer. They range from 2 × 10−3 to 5 × 10−3 m s−1), and are inversely proportional to the Ombla Spring discharge. Continuous measurements of the ground water level by several piezometers located in the karst hinterland of the Ombla Spring and simultaneous measurement of the discharge made it possible to define discharge curves of the Ombla Spring dependent upon the ground water levels at various locations. Characteristic features of the discharge curves made the identification of the position and dimensions of the main karst conduits possible
Analyse der an Messstationen Zagreb Grič und Split Marjan gemessenen Lufttemperaturen im kontext von Klimanormalperioden
Full text linkU našim sredstvima javnog informiranja, osobito u udarnim televizijskim emisijama, čuje se vrlo često da je temperatura bila ili da će biti viša od prosječne, tj. iznadprosječno visoka. Pri tome se gotovo nikada ne kaže o kojem se prosjeku radi, tj. na koje se vremensko razdoblje ta usporedba odnosi. Isto tako se rijetko može čuti koliko je ta iznadprosječna temperatura viša od one prosječne. Pitanje je što je to klimatološki prosjek ili klimatološka normala. Svjetska meteorološka organizacija (WMO, World Meteorological Organisation) je tijekom dvadesetog stoljeća definirala standardna klimatska razdoblja trajanja 30 godina. Klimatološka normala predstavlja mjerilo koje služi za procjenu trenutačnih klimatskih uvjeta u usporedbi s onim prethodnim(a). Komisija za klimatologiju WMO-a je preporučila da se standardna klimatska razdoblja pomiču svakih 10 godina umjesto 30 godina (https://public.wmo.int/en/media/news/updated-30-year-reference-period-reflects-changing-climate). Posljednje važeće standardno klimatsko razdoblje 1981.-2010. je još uvijek na snazi. U pripremi je novo klimatski normalo (New Climate Normal) 30-godišnje razdoblje koje će obuhvatiti period od 1991. do 2020. Očekuje se da će ta promjena nastupiti od početka 2022. godine. U radu su se na podacima temperatura zraka izmjerenih na meteorološkim postajama Split Marjan i Zagreb Grič izučile razlike u zaključivanju o recentnim promjenama temperature zraka u drugoj dekadi trećeg milenija (2011.-2020.). Analizirana su sljedeća četiri djelomično preklapajuća klimatološka standarda: 1961.-1990.; 1971.-2000.; 1981.-2010. i 1991.-2020. Analize obavljene u ovom radu ukazale su na neophodnost stalnog mijenjanja/ažuriranja klimatološkog standarda za procjene varijacija recentnih temperatura zraka. S obzirom na nagli porast temperature zraka u zadnjem klimatološkom standardu (1991.-2020.) to razdoblje treba biti korišteno za usporedbu i procjenu recentnih temperaturnih prilika, ali i drugih klimatskih parametara.In our public media, particularly primetime TV broadcasts, it is very often heard that the temperature was or will be higher than the average, i.e. above average. At the same time, it is almost never said which average it is, i.e. to which time period the comparison refers. It is also rare to hear how much this above average temperature is higher than the average one. This raises the issue of what is a climate average or a climate normal. During the twentieth century, the World Meteorological Organization (WMO) defined standard climate periods as those lasting 30 years. The climate normal represents a measure that is used for evaluating current climate conditions in comparison with the previous one(s). The Commission for Climatology of the WMO has recommended that, instead of every 30 years, standard climate periods should change every 10 years (https://public.wmo.int/en/media/news/updated-30-year-reference-period-reflects-changing-climate). The last standard climate period of 1981-2010 is still valid. The New Climate Normal 30-year period is being prepared. It will cover the period from 1991 to 2020 and is expected to start from the beginning of 2022. The paper uses air temperature data measured at meteorological stations Split Marjan and Zagreb Grič to study the differences in conclusions about the recent changes in air temperature in the 2nd decade of the 3rd millennium (2011-2020). The following 4 partially overlapping climate standards were analysed: 1961-1990, 1971-2000, 1981-2010 and 1991-2020. The analyses conducted in the paper indicate a necessity of constant changes / updates of the climate standard for estimating the variations in recent air temperatures. Considering a sudden increase in air temperature in the latest climate standard (1991-2020), it is this period that should be used for comparison and assessment of recent temperature conditions, as well as other climate parameters.In kroatischen Massenmedien, namentlich in Fernsehsendungen zur Hauptsendezeit, hört man oft, dass die Temperatur höher als die durchschnittliche Temperatur, d.h. überdurchschnittlich hoch war oder sein wird. Dabei wird fast nie gesagt, um welchen Durchschnitt es geht, d.h. auf welche Periode sich der Vergleich bezieht. Außerdem kann man nur selten hören, wie viel höher diese überdurchschnittliche Temperatur ist im Vergleich zur durchschnittlichen Temperatur. Die Frage ist nämlich, welche klimatologischen Mittelwerte oder Klimanormalperiode gelten. Die Weltorganisation für Meteorologie (WMO, World Meteorological Organisation) legte die Klimanormalperioden für das 20. Jahrhundert auf 30 Jahre fest. Die für den Zeitraum der Normalperiode gemessenen Mittelwerte der Klimadaten dienen als Referenz für die Auswertung von momentanen Klimabedingungen im Vergleich zu früheren Klimabedingungen. Die Fachkommission für Klimatologie der WMO empfiehlt, dass die Klimanormalperioden zukünftig alle zehn Jahre aktualisiert werden. Die geltende Bezugsperiode ist die Klimanormalperiode 1981-2010. Die neue 30-jährige Klimanormalperiode (New Climate Normal) für den Zeitraum 1991-2020 wird gerade vorbereitet und soll seit dem Beginn 2022 gelten.
In der Arbeit wurden Unterschiede anhand der an den Messstationen Split Marjan und Zagreb Grič gemessenen Daten über Lufttemperaturen festgestellt in der Bewertung der Änderungen der Lufttemperatur im zweiten Jahrzehnt des dritten Jahrtausends (2011-2020). Die folgenden vier teilweise überlappenden Klimanormalperioden – 1961-1990, 1971-2000, 1981-2010 und 1991-2020 – wurden analysiert. Die Analysen weisen auf die Notwendigkeit einer kontinuierlichen Aktualisierung der Klimanormalperioden zur Beurteilung von letzten Lufttemperaturschwankungen hin. In Bezug auf den plötzlichen Anstieg der Lufttemperatur in der letzten Klimanormalperiode (1991-2020) soll diese Periode Referenzperiode für Vergleich und Beurteilung von jetzigen Temperaturbedingungen sowie anderer Klimadaten sein
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