The long-term variability of the periods with rainfall deficit in the upper Vistula river basin
Authors:
- Marta Cebulska
Abstract
The study investigated the periods with precipitation showing the deviation from the standard, based on sums of the monthly and annual precipitation from 30 year period, i.e. in turn from the years 1984-2013 from 64 measuring stations located in the upper Vistula river basin. The area considered for the study covers the surface of 50 731,8 km2 and constitutes 25% of the entire area of Vistula river basin. Slightly over 90% of the upper Vistula river basin is located in the territory of Poland. The upper Vistula basin within Polish borders takes about 15% of the whole country area [3]. The sequences of monthly precipitation from the period of study were obtained from the Institute of Meteorology and Water Management - National Research Institute. The evaluation in variability of the lowest monthly sums of rainfalls in the individual measuring stations was also carried out in annual and multiannual course. The distribution of drought periods with various intensity was presented in annual and multiannual course. The periods with abnormally low precipitation were determined while considering the drought identification index, including the Relative Precipitation Index (RPI) [4,5] and the Standardized Precipitation Index (SPI) ) [6,7]. The lowest monthly sums of rainfalls occur in the whole year with the highest their frequency from October (20%) to April (nearly 10%). In the remaining months their occurrence frequency does not exceed 5%. In the period under consideration, in all measuring stations there was at least one month whose total rainfall did not exceed 4 mm. It happened in November 2011[1]. During the study period there were months with very low precipitation, even below 10% of multiannual average - over most of the area it happened in November 2011, in April 2009, as well as in October 1995 and 2010. Accordingly, the periods with precipitation deficit may occur in dry, wet and average seasons. Based on the drought intensity calendar developed for particular months there was determined the longest duration sequence of period with rainfall below 75% of the standard for the multiannual average precipitation. It occurred in Klimontow and lasted for 8 months. It happened from September 1995 to April 1996. In the area of study the extremely dry month happened on average every 5 years in Warszowice, Wisłok Wielki, Goczałkowice, Tychy, Ochotnica Górna and in Roztoki; whereas in Polana averagely 2 extremely dry months occurred in 3 years. In the years 1985, 1998, 2001, 2007, 2009, 2010 in all measuring stations, the total precipitation exceeded 90% of average annual rainfall. While considering the annual rainfalls as well as the classification developed by Kaczorowska [4], the dry period with various intensity happened in this area in 1993 and 2003 when it was at least 60 stations that recorded the annual rainfalls below 90% of average annual rainfall, also in the years 1984, 1986, 2011 there were observed the rainfalls below 90% of the standard, which covered at least 65% of measuring stations. In case of the annual rainfalls based on the SPI index the moderately dry years were selected (over the years indicated at RPI with precipitation below 90% of the standard) – it happened in 2012 and 1988-1992 with exception of 1989. The highest frequency of the dry spells with various intensity degrees within the multiannual period was noticed in September and in October – 13 cases; the least in August – 8 cases. The extremely dry month in view of SPI turned out to be April 2009, June 2003, July 1994, August 2013, October 1995, November 2011 and December 2004. In the area of the upper Vistula river basin there were selected more dry spells with various drought intensity while using the criterion of Relative Precipitation Index (RPI) [2]. However, when comparing a number of stations with dry spells determined according to RPI and SPI, a slight difference was found in their number in a given year - the maximum difference was 5 stations in 1990.
- Record ID
- CUT6a3d7a99138c485bb44d382896bbadfc
- Publication categories
- ; ;
- Author
- Pages
- 79-80
- Other elements of collation
- Bibliografia (na s.) - 80; Bibliografia (liczba pozycji) - [7]
- Book
- Âvors'kij B. Ì., B. Ì. Âvors'kij Tihanovič E. E., E. E. Tihanovič Smalìjčuk A. D. A. D. Smalìjčuk (eds.): Dovgotermìnovì sposterežennâ dovkìllâ: dosvìd, problemi, perspektivi : materìali Mìžnarodnogo naukovogo semìnaru, prisvâčenogo 75-rìččû z dnâ narodžennâ B. P. Muhi ì 50-rìččû roboti Roztoc'kogo landšaftno-geofìzičnogo stacìonaru L'vìvs'kogo nacìonal'nogo unìversitetu ìmenì Ivana Franka, L'vìv – Brûhovičì, 10-12 travnâ 2019 roku, 2019, L'vìv, LNU ìmenì Ivana Franka
- Keywords in English
- the lowest monthly precipitation, meteorological drought, Standardized Precipitation Index(SPI), Relative Precipitation Index (RPI)
- Language
- eng (en) English
- Score (nominal)
- 0
- Uniform Resource Identifier
- https://cris.pk.edu.pl/info/article/CUT6a3d7a99138c485bb44d382896bbadfc/
- URN
urn:pkr-prod:CUT6a3d7a99138c485bb44d382896bbadfc
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