Combined analysis of precipitation and water deficit for drought hazard assessment |
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| Authors: | Tamara Tokarczyk Wiwiana Szalińska |
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| Institution: | 1. Institute of Meteorology and Water Management, National Research Institute, Wroclaw, PolandTamara.Tokarczyk@imgw.pl;3. Institute of Meteorology and Water Management, National Research Institute, Wroclaw, Poland |
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| Abstract: | AbstractThe combined analysis of precipitation and water scarcity was done with the use of the Standardized Precipitation Index (SPI) and the Standardized Runoff Index (SRI), developed as a monthly, two-variable SPI-SRI indicator to identify different classes of hydrometeorological conditions. Stochastic analysis of a long-term time series (1966–2005) of monthly SPI-SRI indicator values was performed using a first-order Markov chain model. This provided characteristics of regional features of drought formation, evolution and persistence, as well as tools for statistical long-term drought hazard prediction. The study was carried out on two subbasins of the Odra River (Poland) of different orography and land use: the mountainous Nysa K?odzka basin and the lowland, agricultural Prosna basin. Classification obtained with the SPI-SRI indicator was compared with the output from the NIZOWKA model that provided identification of hydrological drought events including drought duration and deficit volume. Severe and long-duration droughts corresponded to SPI-SRI Class 3 (dry meteorological and dry hydrological), while severe but short-term droughts (lasting less than 30 days) corresponded to SPI-SRI Class 4 (wet meteorological and dry hydrological). The results confirm that, in Poland, meteorologically dry conditions often shift to hydrologically dry conditions within the same month, droughts rarely last longer than 2 months and two separate drought events can be observed within the same year. |
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| Keywords: | drought hazard hydrological drought Markov chain meteorological drought radar plots Standardized Precipitation Index (SPI) Standardized Runoff Index (SRI) |
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