On the instabilities of estimated distributions of the POT (Peak Over Threshold) low flow characteristics

• Autorzy: Jakubowski W.
• Języki publikacji: EN

Abstrakty

EN

In a certain stream gauge profile, consider the low flow flows determined with the POT (Peak Over Threshold) method. Each of the flows can be described by three characteristics – deficit, duration and minimal flow. Values of the three-dimensional random variable depend on the choice of truncation level Qg (threshold flow) – POT method parameter. It is typically assumed that the threshold level is included within the range from Q95% to Q60% (Tallaksen, van Lanen 2004). However, in computational practice the Qg value is determined at the level of either Q90% to Q70%. This choice is made mainly from the hydrological (not statistical) point of view. In this paper the influence of the threshold flow on the form of estimated distributions of each of the above three characteristics is considered. The following distributions are chosen: − GEV (generalised extreme value distribution) – while examining the distribution of extremes; − log-normal – in the non-extreme case. In each of the examined stream gauge profiles the following algorithm was used: 1. from the curve of duration sums, two flow values Q90% and Q55% are chosen 2. for each flow from the range (Q90%, Q55%), using the Zelenhasić method (1987), a three-dimensional sequence is determined of observed deficits, durations and minimal flow values; 3. for each of the one-dimensional sequences, the parameters of the above distributions are estimated. The variability of the estimated quantiles and their intervals of confidence were shown with the example of three gauge profiles – Kuripapango (New Zealand), Bogusław (Prosna) and Bystrzyca Kłodzka (Nysa Kłodzka).

Słowa kluczowe

EN

instability; distribution; river; water flow; low flow; threshold

• Wydawca: -
• Czasopismo: Meteorology Hydrology and Water Management. Research and Operational Applications
• Rocznik: 2015
• Tom: 03
• Numer: 2
• Opis fizyczny: p.33-38,fig.,ref.

Twórcy

autor

Jakubowski W.

• Department of Mathematics, The Faculty of Environmental Engineering and Geodesy, Centrum Naukowo-Dydaktyczne, Wroclaw University of Environmental and Life Sciences, Grunwaldzka Street 55, 50-357 Wroclaw, Poland

Bibliografia

• Bonacci O., 1993, Hydrological identification of drought, Hydrological Processes, 7 (3), 249-262, DOI: 10.1002/hyp.3360070303
• Bower D., Hannah D.M., McGregor G.R., 2004, Techniques for assessing the climatic sensitivity of river flow regimes, Hydrological Processes, 18 (13), 2515-2543; DOI: 10.1002/hyp.1479
• Coles S., 2001, An introduction to statistical modeling of extreme values, Springer – Verlag London Limited, 209 pp.
• Gustard A., Demuth S. (eds.), 2009, Manual on Low-flow: Estimation and Prediction, Operational Hydrology Report No. 50, WMO-No. 1029, Koblenz
• Hisdal H., Tallaksen L.M., 2000, Drought event definition, Technical Report to the AR IDE Project 6, Department of Geophysics, University of Oslo, available at http://www.hydrology.uni-freiburg.de/forsch/aride/navigation/publications/pdfs/aride-techrep6.pdf (data access 26.10.2015)
• Hisdal H., 2002, Regional aspects of droughts, Faculty of Mathematics and Natural Sciences, University of Oslo, available at http://www.geo.uio.no/edc/downloads/phd_thesis_hisdal_\2002.pdf (data access 26.10.2015)
• Hisdal H., Tallaksen L.M., Frigessi A., 2002, Handling nonextreme events in extreme value modelling of streamflow droughts, [in:] FRIEND 2002 – Regional Hydrology: Bridging die Gap between Research and Practice, Proceedings of the Fourth International FRIEND Conference held at Cape Town, South Africa, IAHS Publ. 274, 281-288, available at http://hydrologie.org/redbooks/a274/iahs_274_281.pdf (data access 26.10.2015)
• Jakubowski W., Radczuk L., 2004, Nizowka 2003 software, [in:] Hydrological Drought, 48, Processes and estimation methods for streamflow and groundwater, L.M. Tallaksen, H.A.J. van Lanen (eds.), Amsterdam
• Jakubowski W., 2011, Probability distributions in the estimation of hydrological drought (in Polish), Monografie Uniwersytetu Przyrodniczego we Wrocławiu, CXVI, 178 pp.
• Kaznowska E., 2011, Analysis of low flow characteristics and drought frequency in agricultural attachments, [in:] Prediction and Reduction of Diffuse Pollution, Solid Emission and Extreme Flows from Rural Areas – case study of small agricultural catchment, Wydawnictwo SGGW, 27-46, available at http://ziw.sggw.pl/zaklad/monogra/rozdzial_2.pdf (data access 26.10.2015)
• Ozga-Zielińska M., 1990, Droughts and floods – their definition and modeling (in Polish) Przegląd Geofizyczny, XXXV (1-2), 33-44
• Ozga-Zielińska M., Brzeziński J., 1997, Applied Hydrology (in Polish), PWN, Warszawa, 323 pp.
• Smakhtin V.U., 2001, Low flow hydrology: a review, Journal of Hydrology, 240 (3-4), 147-186, DOI: 10.1016/S0022-1694(00)00340-1
• Tallaksen L.M., 2000, Streamflow drought frequency analysis, [in:] Drought and drought mitigation in Europe, V.J. Vogt, F. Somma (eds.), Advances in Natural and Technological Hazards Research, 14, 103-117, DOI: 10.1007/978-94-015-9472-1_8
• Tallaksen L.M., van Lanen H.A.J. (eds.), 2004, Hydrological Drought, 48, Processes and estimation methods for streamflow and groundwater, Elsevier Science B.V., Amsterdam, 579 pp.
• Tokarczyk T., Jakubowski W., 2006, Temporal and spatial changeability of drought in mountain catchments of the Nysa Klodzka basin, [in:] Climate Variability and Change – Hydrological Impacts, Proceedings of the Fifth FRIEND World Conference held at Havana, Cuba, IAHS Publ. 308, 139-144, available at http://iahs.info/uploads/dms/13650.29-139-144-91-308-Taka.pdf (data access 30.10.2015)
• Yevjevich V., 1967, An objective approach to definition and investigations of continental hydrologic droughts, Hydrology Papers, 23, Colorado State University, Fort Collins, available at https://dspace.library.colostate.edu/bitstream/handle/10217/61303/HydrologyPapers_n23.pdf?sequence=1 (data access 30.10.2015)
• Zelenhasić E., Salvai A., 1987, A method of streamflow drought analysis, Water Resources Research, 23 (1), 156-168; DOI: 10.1029/WR023i001p00156