Observed changes in extreme precipitation in Poland: 1991–2015 versus 1961–1990

Theoretical and Applied Climatology, Jan 2018

Several episodes of extreme precipitation excess and extreme precipitation deficit, with considerable economic and social impacts, have occurred in Europe and in Poland in the last decades. However, the changes of related indices exhibit complex variability. This paper analyses changes in indices related to observed abundance and deficit of precipitated water in Poland. Among studied indices are maximum seasonal 24-h precipitation for the winter half-year (Oct.–March) and the summer half-year (Apr.–Sept.), maximum 5-day precipitation, maximum monthly precipitation and number of days with intense or very intense precipitation (respectively, in excess of 10 mm or 20 mm per day). Also, the warm-seasonal maximum number of consecutive dry days (longest period with daily precipitation below 1 mm) was examined. Analysis of precipitation extremes showed that daily maximum precipitation for the summer half-year increased for many stations, and increases during the summer half-year are more numerous than those in the winter half-year. Also, analysis of 5-day and monthly precipitation sums show increases for many stations. Number of days with intense precipitation increases especially in the north-western part of Poland. The number of consecutive dry days is getting higher for many stations in the summer half-year. Comparison of these two periods: colder 1961–1990 and warmer 1991–2015, revealed that during last 25 years most of statistical indices, such as 25th and 75th percentiles, median, mean and maximum are higher. However, many changes discussed in this paper are weak and statistically insignificant. The findings reported in this paper challenge results based on earlier data that do not include 2007–2015.

A PDF file should load here. If you do not see its contents the file may be temporarily unavailable at the journal website or you do not have a PDF plug-in installed and enabled in your browser.

Alternatively, you can download the file locally and open with any standalone PDF reader:

https://link.springer.com/content/pdf/10.1007%2Fs00704-018-2372-1.pdf

Observed changes in extreme precipitation in Poland: 1991–2015 versus 1961–1990

Observed changes in extreme precipitation in Poland: 1991-2015 versus 1961-1990 Iwona Pińskwar 0 Adam Choryński 0 Dariusz Graczyk 0 Zbigniew W. Kundzewicz 0 0 Potsdam Institute for Climate Impact Research , Potsdam , Germany 1 Iwona Pińskwar Several episodes of extreme precipitation excess and extreme precipitation deficit, with considerable economic and social impacts, have occurred in Europe and in Poland in the last decades. However, the changes of related indices exhibit complex variability. This paper analyses changes in indices related to observed abundance and deficit of precipitated water in Poland. Among studied indices are maximum seasonal 24-h precipitation for the winter half-year (Oct.-March) and the summer half-year (Apr.-Sept.), maximum 5-day precipitation, maximum monthly precipitation and number of days with intense or very intense precipitation (respectively, in excess of 10 mm or 20 mm per day). Also, the warm-seasonal maximum number of consecutive dry days (longest period with daily precipitation below 1 mm) was examined. Analysis of precipitation extremes showed that daily maximum precipitation for the summer half-year increased for many stations, and increases during the summer half-year are more numerous than those in the winter half-year. Also, analysis of 5-day and monthly precipitation sums show increases for many stations. Number of days with intense precipitation increases especially in the north-western part of Poland. The number of consecutive dry days is getting higher for many stations in the summer half-year. Comparison of these two periods: colder 19611990 and warmer 1991-2015, revealed that during last 25 years most of statistical indices, such as 25th and 75th percentiles, median, mean and maximum are higher. However, many changes discussed in this paper are weak and statistically insignificant. The findings reported in this paper challenge results based on earlier data that do not include 2007-2015. 1 Introduction According to the Clausius-Clapeyron law, there is more room for water vapour in the warming atmosphere; hence, potential for intense precipitation grows. The 5th Assessment Report of the IPCC (2014) states that it is very likely that global nearsurface and tropospheric air humidity has increased since the 1970s. Also, frequency and intensity of heavy precipitation events has likely increased in North America and Europe, as a result of anthropogenic forcing, which leads to an intensification of the water cycle. Existing analyses of trends in hydrometeorological data cover large scales, that is the global scale: e.g. Groisman et al. 2005 ; Alexander et al. 2006 ; Donat et al. 2013 ; the European scale: e.g. Zolina et al. 2010 ; Zolina Institute for Agricultural and Forest Environment, Polish Academy of Sciences, Bukowska 19, 60-809 Poznań, Poland task to enable better interpretation of possible future trends. Increase of the extreme abundance of water has potential impacts, including floods, erosion, flash floods and inundation. Deficits of water may affect water resources, agriculture and ecosystems. Several episodes of extreme precipitation excess and extreme precipitation deficit, leading to dramatic floods and droughts, with considerable economic and social impacts, have occurred in Europe in the last decades. Major floods occurred in the decade of the 1990s, such as in 1993 and 1995 (the basins of the River Rhine and its tributaries), in 1994 (the Mediterranean region) and in 1997 (Central Europe). In the twenty-first century, serious floods occurred in 2000 in Western Europe (UK, Italy, France and Switzerland), in 2005, 2007 and 2010. The most severe floods with the absolute record of annual flood loss in Europe, exceeding €20 billion (nominal value, unadjusted for inflation) were observed in August 2002 (Kundzewicz et al. 2013) . One year after these great floods, in the summer of 2003, many parts of Europe experienced severe droughts and heat waves. The summer of 2010, exceptionally warm and dry in Eastern Europe and large parts of Russia, was more severe than the hottest summer of 2003 because of higher amplitude and spatial extent. During that time, extensive fires across western Russia occurred. According to projections, these anomalously warm and dry episodes are recognised as summers which are likely to occur more frequently in the later decades of the twenty-first century (Beniston 2004, Barriopedro et al. 2011) . In Poland, destructive floods as a result of abundant rainfall with high material damage and tens of fatalities occurred in 1970, 1997, 2001 and 2010. The most severe floods of 1997 and 2010 were preceded by very intense and long-lasting precipitation over large areas, so in consequence, large parts of Poland were flooded (Kundzewicz et al. 2012) . Noticeable is an increasing number of local floods in urban areas (flash floods) caused by intensive rainfall. In 2017, several cities in Poland were affected by abundan (...truncated)


This is a preview of a remote PDF: https://link.springer.com/content/pdf/10.1007%2Fs00704-018-2372-1.pdf

Iwona Pińskwar, Adam Choryński, Dariusz Graczyk, Zbigniew W. Kundzewicz. Observed changes in extreme precipitation in Poland: 1991–2015 versus 1961–1990, Theoretical and Applied Climatology, 2018, pp. 1-15, DOI: 10.1007/s00704-018-2372-1