- Tytuł:
- Niżówka jako wskaźnik suszy hydrologicznej
- Autorzy:
-
Tokarczyk, Tamara
Radczuk, Laura
Zaleski, Janusz - Powiązania:
- https://bibliotekanauki.pl/books/2080712.pdf
- Data publikacji:
- 2010
- Wydawca:
- Instytut Meteorologii i Gospodarki Wodnej - Państwowy Instytut Badawczy
- Opis:
-
Niniejsza praca stanowi próbę opisania niżówki modelami probabilistycznym i deterministycznym, które całościowo tworzą podejście hybrydowe statystyczno-deterministyczne. W języku potocznym słowo model ma dwa podstawowe
zbliżone do siebie znaczenia. W pierwszym zasadniczą procedurą jest odwzorowanie oryginału przy zachowaniu jego istotnych cech. W tym znaczeniu model jest kopią oryginalnego obiektu i odznacza się znacznym do niego podobieństwem. Model nie jest jednak identyczny z oryginałem, zachowuje jedynie cechy istotne z pewnego określonego punktu widzenia. Inne właściwości obiektu mogą być w modelu pominięte (zredukowane). Drugie znaczenie słowa „model” podkreśla jego uniwersalność. Nawiązuje ono do hipotezy myślowej o możliwości identyfikacji obiektu przez porównanie go z obiektem wzorcowym. Model w tym sensie pełni rolę wzorca, którego można użyć do analizy każdego podobnego do niego obiektu rzeczywistego. Definicja ta jest zgodna z duchem platońskiej nauki o świecie idealnym. Modelem w drugim ujęciu są np. wzorce miary i wagi, a w pierwszym – interesujące nas najbardziej – modele fizyczne i matematyczne obiektów, zjawisk i procesów przyrodniczych.
LOW FLOW AS AN INDICATOR OF HYDROLOGICAL DROUGHT Summary The occurrence of drought is one of the characteristic features of Polish climate. In this country, drought usually lasts for many weeks and covers considerable area causing economic and social losses. Drought differs from other hydrological and meteorological phenomena not only in time and spatial range but the influence it has on the remaining fields as well. Even if droughts’ direct, negative impact is slight or has unsubstantial scope, the observed indirect impact on various fields may be significant and long-lasting. Due to the influence drought has on environment, economy and society, more, and more research and implementation works are devoted to issues concerning its occurrence, risk assessment, monitoring and forecasting. Literature indicates that hydrological droughts are most often associated with low flow periods on rivers. Only Zielińska (1963) characterizes low flow with so called low flow module, which is the product of duration of low flow and the lowest base flow which gives considerably overestimated values of base flow volume. The dissertation has a methodical nature. Defining hydrological drought index required both formulating a definition of hydrological drought and methods for their divestment from the set of observed low flows which has been achieved through the undertaken research. In presented thesis product (Di x Ti) is used as a hydrological drought index (WSH). It characterizes phenomenon intensity. For maximum low flow it has the maximum value. What is more, the term ‘extreme hydrological drought likelihood’ is introduced and described as hydrological drought index (WSH95 = D95 x T95) that is the product of streamflow deficiency with a 95% probability of non-exceedance and the duration of low flow with a 95% probability of non-exceedance. Extreme drought likelihood is defined as a drought which is real in terms of physics and sequence of occurring events which is confirmed by its frequency of occurrence in researched river basins at the level once or twice during the researched forty years (1966-2005). On the basis of the analyses carried out in this work, the following conclusions can be drawn: 1. By characterizing low-flow in terms of probabilistic and deterministic models, which in turn form the hybrid statistical-deterministic approach, both a description of the cause-effect (deterministic model) and random phenomena of low-flow (probabilistic model) is included. 2. Due to the analysis of drought index combined with the method of complex cartogram droughts can be divided into 5 classes, that is (i) short-term low flow, (ii) longterm low flow, (iii) moderate hydrological drought, (iv) severe hydrological drought, (v) extreme hydrological drought. Short-term low flow class comprises of low flows with the streamflow deficiency lower or equal to D50% and duration to 30 days. Long-term low flow class comprises of low flows with the non-exceedance probability to D80% and duration to 30 days. Moderate hydrological drought class comprises of low flows with non-exceedance probability to D90% and duration to 120 days. Strong hydrological drought class comprises of low flows with non-exceedance probability to D95% and duration to 180 days whereas extreme low flow hydrological drought class comprises of low flows with non-exceedance higher than D95% and duration which is no longer than 180 days. 3. Elaborated hybrid models may be used for the evaluation of vulnerability of ungauged river basins to the occurrence of droughts. 4. Determined dependence of hydrological drought index (WSH95) specified for extreme hydrological drought likelihood from the potential of groundwater recharge (ΔQB = QBmax – QBmin) provides the basis for determining the magnitude of the potential power of groundwater recharge, at which there is occurrence of extreme hydrological drought. 5. The interdependence between the relative streamflow deficiency (Dw) and recession rate (α) from the recession curve indicates the susceptibility of river basins to the occurrence of low flows and hydrological droughts. 6. The interdependence between the probability of the occurrence of streamflow volume deficit higher than zero (ppD > 0) and active retention of dynamic exchange of groundwater (RSAWDWP) enables to divide river basins of low and high susceptibility to the low flow and hydrological droughts occurrence. 7. In researched river basins simultaneous occurrence of low-flow long periods of drought and hydrological drought were judged on the basis of the ratio of standardized climatic water balance for the summer semester. 8. The determined correlation between WSH and KBW gives the opportunity to join the evaluation of atmospheric and hydrological drought. 9. Hybrid models were also elaborated for lowland Prosno river basin. The quality of achieved models was evaluated on the basis of determination coefficient. Its value indicates a strong relation. Therefore, the use of the models is similar to the case of Nysa Kłodzka river basin. The applicability of the models applies only to river basins which are characterized by high hydrological similarity. The obtained research outcomes incline to formulate further directions of the study on the issue of hydrological drought: • underlying hydrological processes generating droughts, including droughts in winter time, • examination of the process of drought development from atmospheric to hydrological one, its time and spatial scope, • combining atmospheric circulation pattern with low flows and hydrological droughts, • examination of drought development along the river, • near-real time drought monitoring system, • the influence of climate variability, changes in spatial planning and human activity on the frequency of low flow and hydrological occurrence of droughts. - Dostawca treści:
- Biblioteka Nauki
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