The objective of this paper is to compare the results of two distributed snow models based on different approach to snow accumulation and melt. Model WaSiM is based on the degree-day approach, while model UEB-EHZ is an energy-based model. Simulations in the mountain catchment of Jalovecký creek in winters 1989-2001 showed that both approaches can produce similar results. Model parametrization is more important than basic approach to snow accumulation and melt. Therefore, model UEB-EHZ which took into acccount influence of forest on radiation reduction and snow drift, performed better for the forest sites. The paper presents also brief overview of snow accumulation and melt modelling including calibration and verification of distributed models. Finally, it shows some outupts which can be provided by distributed snow models. and Príspevok je venovaný porovnaniu dvoch distribuovaných matematických modelov akumulácie a topenia snehu s rôznym prístupom k modelovaniu snehu. V horskom povodí Jaloveckého potoka boli hodnotené výsledky energeticky založeného modelu UEB-EHZ a modelu WaSiM, vychádzajúceho z metódy teplotného indexu pre zimy 1988/89 - 2000/2001. Porovnanie výsledkov oboch modelov ukázalo, že pokiaľ ide o základný prístup k modelovaniu topenia snehu (energetická bilancia alebo teplotný index), nemohli sme v danom povodí určiť, ktorý z nich viedol k lepším výsledkom. Väčší vplyv na simuláciu vodnej hodnoty snehu ako výber základného prístupu k modelovaniu akumulácie a topenia snehu, má parametrizácia konkrétneho modelu. V modeli UEB-EHZ bol napríklad čiastočne zahrnutý vplyv lesa na globálne žiarenie a podmienky ukladania snehu (drift). Preto bolo topenie snehovej pokrývky v lese týmto modelom simulované reálnejšie ako modelom WaSiM. Okrem porovnania výsledkov dvoch základných prístupov k modelovaniu akumulácie a topenia snehu v horskom povodí príspevok ukazuje aj niektoré výstupy, ktoré možno získať pomocou distribuovaného snehového modelu a stručne sa zaoberá diskusiou o kalibrácii a validácii takéhoto modelu.
This study evaluates MODIS snow cover characteristics for large number of snowmelt runoff events in 145 catchments from 9 countries in Europe. The analysis is based on open discharge daily time series from the Global Runoff Data Center database and daily MODIS snow cover data. Runoff events are identified by a base flow separation approach. The MODIS snow cover characteristics are derived from Terra 500 m observations (MOD10A1 dataset, V005) in the period 2000–2015 and include snow cover area, cloud coverage, regional snowline elevation (RSLE) and its changes during the snowmelt runoff events. The snowmelt events are identified by using estimated RSLE changes during a runoff event. The results indicate that in the majority of catchments there are between 3 and 6 snowmelt runoff events per year. The mean duration between the start and peak of snowmelt runoff events is about 3 days and the proportion of snowmelt events in all runoff events tends to increase with the maximum elevation of catchments. Clouds limit the estimation of snow cover area and RSLE, particularly for dates of runoff peaks. In most of the catchments, the median of cloud coverage during runoff peaks is larger than 80%. The mean minimum RSLE, which represents the conditions at the beginning of snowmelt events, is situated approximately at the mean catchment elevation. It means that snowmelt events do not start only during maximum snow cover conditions, but also after this maximum. The mean RSLE during snowmelt peaks is on average 170 m lower than at the start of the snowmelt events, but there is a large regional variability.
Flooding remains the most widely distributed natural hazard in Europe, leading to significant economic and social impact. Earth observation data is presently capable of making fundamental contributions towards reducing the detrimental effects of extreme floods. Technological advance makes development of online services able to process high volumes of satellite data without the need of dedicated desktop software licenses possible. The main objective of the case study is to present and evaluate a methodology for mapping of flooded areas based on MODIS satellite images derived indices and using state-of-the-art geospatial web services. The methodology and the developed platform were tested with data for the historical flood event that affected the Danube floodplain in 2006 in Romania. The results proved that, despite the relative coarse resolution, MODIS data is very useful for mapping the development flooded area in large plain floods. Moreover it was shown, that the possibility to adapt and combine the existing global algorithms for flood detection to fit the local conditions is extremely important to obtain accurate results.
We outline a novel solution to Moore’s paradox within the framework of update semantics, which explains Moorean absurdity in terms of non-cohesiveness. It is argued that, unlike the outlined solution, Gillies’ treatment of the paradox within this framework is not satisfactory., Načrtneme nové řešení Moorova paradoxu v rámci aktualizační sémantiky, která vysvětluje Mooreanovu absurditu z hlediska nekoheze. Tvrdí se, že na rozdíl od nastíněného řešení není Gilliesovo zacházení s paradoxem v tomto rámci uspokojivé., and Igor Sedlár
Precipitation is important input into the hydrological system. With its time and space distribution significantly influences outflow from the catchment. This contribution deals with movement of rainfall events in Prague area. Velocities and directions of storm movement have been estimated on the basis of two years measurement from PVS a.s. rain-gauge network. Mostly convective rainfall events have been evaluated. There are estimated mean parameters for whole area and partial values of rainfall movement for nine subareas, into which the Prague area has been divided. Results can be used for estimation of space-time rainfall distribution in the catchment. and Srážka je důležitou vstupní veličinou hydrologického systému. Svým časovým a plošným rozdělením výrazně ovlivňuje odtok z povodí. Předkládaný příspěvek se zabývá pohybem dešťů na území Prahy. Na základě dvouletých měření srážkoměrné sítě PVS a.s. byly stanoveny rychlosti posunu a směry pohybu převážně konvektivních dešťových událostí v zájmové oblasti. Jsou stanoveny průměrné parametry pohybu pro celou oblast a dílčí hodnoty rychlostí a směrů pohybu srážky v devíti podoblastech, na které bylo území Prahy rozděleno. Výsledné hodnoty pohybu srážek lze využít pro stanovení časoprostorového průběhu srážky v povodí.
Method of groundwater flow velocity determination in sand and gravel aquifer of Danube river is described in the paper. The solution in which seasonal changes of ground and river water temperatures are used is original. It gives good opportunity for solution of different hydrogeological and water management problems. The method application is demonstrated on the example of Sihoť well field in Bratislava Karlova Ves. Results were used in design ground water zones protection. and V príspevku je opísaná metóda určovania rýchlosti prúdenia podzemnej vody v náplavoch rieky Dunaj. Metodický postup, pri ktorom sú využité sezónne zmeny teploty podzemnej a povrchovej vody, je pôvodný a dáva pomerne veľké možnosti uplatnenia v hydrogeológii a vo vodárenstve. V príspevku je opísané využitie metódy v konkrétnych prírodnych podmienkach zdroja pitnej vody na ostrove Sihoť v Bratislave-Karlovej Vsi. Takto zídkané výsledky boli použité pri navrhovaní pásiem hygienickej ochrany zdroja.
Typing knowledge is capable to resolve Fitch’s knowability paradox. As I have argued elsewhere, Russellian typing knowledge is immune to the recently raised criticism of the typing approach. This paper focuses on a special form of the criticism proposing a revenge problem raised by Williamson, Hart and also Carrara with Fassio. The basic idea of the revenge Fitch’s paradox employs quantification over type levels. However, the formalism used by the critics is ambivalent. I concentrate only on its two most probable readings, explaining also quantification over types and quantification over orders. As I show in details, if such readings went through, they would violate the typing rules in a direct manner. Hence, there is no revenge for the Russellian typing approach to Fitch’s knowability paradox., Znalost psaní je schopna řešit paradox paradigmatu Fitch. Jak jsem se dohadoval jinde, znalosti ruského psaní jsou imunní vůči nedávno vznesené kritice přístupu k psaní. Tato práce se zaměřuje na speciální formu kritiky, která navrhuje, aby se Williamson, Hart a Carrara s Fassiem pokusili o pomstu. Základní myšlenka pomsty Fitchova paradoxu využívá kvantifikaci nad úrovněmi typu. Formalizmus použitý kritiky je však dvojznačný. Soustředím se pouze na dvě nejpravděpodobnější hodnoty, vysvětlující také kvantifikaci nad typy a kvantifikaci nad zakázkami. Jak ukážu podrobně, pokud by takové čtení proběhlo, porušily by pravidla psaní přímo. Není tedy pomsta za Russellianský typizační přístup k paradoxu znalostí Fitch., and Jiří Raclavský
Providing information on the impacts of climate change on hydrological processes is becoming ever more critical. Modelling and evaluating the expected changes of the water resources over different spatial and time scales can be useful in several fields, e.g. agriculture, forestry and water management. Previously a Budyko-type spatially distributed long-term climate-runoff model was developed for Hungary. This research includes the validation of the model using historical precipitation and streamflow measurements for three nested sub-catchments of the Zala River Basin (Hungary), an essential runoff contributing region to Lake Balaton (the largest shallow lake in Central Europe). The differences between the calculated (from water balance) and the estimated (by the model) mean annual evapotranspiration varied between 0.4% and 3.6% in the validation periods in the sub-catchments examined. Predictions of the main components of the water balance (evapotranspiration and runoff) for the Zala Basin are also presented in this study using precipitation and temperature results of 12 regional climate model simulations (A1B scenario) as input data. According to the projections, the mean annual temperature will be higher from period to period (2011–2040, 2041–2070, 2071–2100), while the change of the annual precipitation sum is not significant. The mean annual evapotranspiration rate is expected to increase slightly during the 21st century, while for runoff a substantial decrease can be anticipated which may exceed 40% by 2071–2100 relative to the reference period (1981–2010). As a result of this predicted reduction, the runoff from the Zala Basin may not be enough to balance the increased evaporation rate of Lake Balaton, transforming it into a closed lake without outflow.
The discrete state space representation of the cascade of linear reservoirs model was used in this case study as the basis for a multilinear flood routing model. The time distribution scheme of model inputs was employed in the setup of the multilinear model and the travel-time parameter of the model was allowed to vary with discharge. The relationship between the flood wave-speed and the discharge for a reach of the Morava River between Moravský Svätý Ján and Záhorská Ves was studied. Five empirical models of that relation have been considered that would fit the data and would be consistent with the physical interpretation of the factors determining the relation. Empirical relations between the wave-speed and discharge were derived for the given river reach using engineering reasoning, linear and nonlinear regression and artificial neural networks. These relationships were used to model the variability of the time parameter in the discrete linear cascade flow routing model. The performance of the multilinear model was verified on ten flood waves. The modelling results showed that the inclusion of empirical information on the variability of the wave-speed with discharge enables satisfactory accuracy of the prediction of the flood propagation process without needing to calibrate the model on pairs of input-output hydrographs. The problem of choosing an appropriate wave-speed discharge relationship was briefly discussed. and Jednou z možností riešenia transformácie povodňových vĺn v korytách tokov je používanie multilineárnych modelov, teda niekoľkých lineárnych modelov odpovedajúcich rôznym odtokovým situáciám. Cieľom prípadovej štúdie bolo preveriť parametrizáciu takejto schémy zohľadňujúcu zmenu postupovej doby vrcholov prietokových vĺn v závislosti na prietoku z hľadiska jeho aplikovateľnosti v podmienkach aluviálneho riečneho úseku s bočnými prítokmi. Za základ zavedenia multilinearity sme zvolili model kaskády lineárnych nádrží, ktorý sme formulovali v stavovom priestore. Použili sme schému tzv. časového delenia vstupov do multilineárneho modelu, pri ktorom sa na výpočte podieľajú rôzne lineárne submodely striedavo za sebou v sérii. Experimentálne sme overili niekoľko spôsobov odhadu závislosti postupovej rýchlosti vrcholov povodňových vĺn od vstupného prietoku do riečneho úseku na rieke Morava medzi profilmi Moravský Svätý Ján a Záhorská Ves. Odvodené závislosti sme použili na výpočet časového parametra multilineárneho modelu, ktorý sme verifikovali na desiatich prietokových vlnách. Výhodou riešenia s premenlivým časovým parametrom kaskády lineárnych nádrží je, že model lepšie napodobňuje vlastnosti riečneho úseku ako lineárny model s parametrami získanými kalibráciou modelu na rade povodňových vĺn, ktorá sa tak stáva prebytočnou.
The discrete state space representation of the Kalinin-Miljukov model was used as the basis for a multilinear discrete cascade flood routing model. The time distribution scheme of model inputs was employed in the setup of the multilinear model and the travel-time parameter of the model was allowed to vary with discharge. The relationship between travel-time and discharge for a reach of the Hron River between Brezno and Banska Bystrica was studied. Empirical models of that relation have been considered that would fit the data and would be consistent with the physical interpretation of the factors determining the relation. Seven such fitted empirical models were used to model the variability of the time parameter in the discrete state space representation of the Kalinin and Miljukov model. The performance of the multilinear model was verified on five flood waves. The modelling results showed that the inclusion of empirical information on the variability of the travel-time with discharge enables satisfactory accuracy of the prediction of the flood propagation process without needing to calibrate the model on pairs of input-output hydrographs. The choice of an appropriate travel-time discharge relationship was briefly discussed. and Jednou z možností riešenia transformácie povodňových vĺn v korytách tokov je používanie multilineárnych modelov, teda niekoľkých lineárnych modelov odpovedajúcich rôznym odtokovým situáciám. Cieľom štúdie bolo preveriť parametrizáciu takejto schémy zohľadňujúcu zmenu postupovej doby vrcholov prietokových vĺn v závislosti na prietoku z hľadiska jeho aplikovateľnosti v podmienkach horského toku s premenlivým bočným prítokom. Za základ zavedenia multilinearity sme zvolili model Kalinina a Miljukova, ktorý sme formulovali v stavovom priestore. Použili sme schému tzv. časového delenia vstupov do multilineárneho modelu, pri ktorom sa na výpočte podieľajú rôzne lineárne submodely striedavo za sebou v sérii. Vzhľadom na silný nemeraný bočný prítok viazali sme premenlivosť koeficienta k modelu na výstupný prietok riečneho úseku (na rozdiel od predošlých prác, kde sme použili vstup do riečneho úseku). Experimentálne sme overili niekoľko spôsobov odhadu tohto parametra pre transformáciu prietoku na Hrone medzi Breznom a Banskou Bystricou. Použili sme postupové doby odhadnuté z 28 historických prietokových vĺn a priemerné hodinové prietoky z Brezna, Mýta, Hronca a Banskej Bystrice z obdobia 1998 až 2002. Výhodou riešenia s pohyblivou postupovou dobou sa ukázalo, že jeden parameter modelu je odvodený z vlastností vstupno-výstupného správania sa riečneho úseku a priama kalibrácia modelu sa tak stáva prebytočnou.