Hydrologic cycle in the Liz catchment is described with an anomaly in the vegetation seasons 1992-1996. Experimental catchment Liz is located in the Šumava Mts. in the Czech Republic. The fully forested watershed is covered by mature spruce forest, and its basic characteristics are as follows: drainage area 0.99 km2, mean discharge 0.01m3 s-1, runoff coefficient 0.38, mean annual air temperature 6.30 oC, average slope 17 %, basin length 1.45 km, water course length 1.43 km, elevation 828-1074 m a.s.l., precipitation sum 851 mm year-1, and runoff depth 324 mm year-1. Air temperature, precipitation, global radiation, and discharge in the closing profile are measured in the catchment. It is characteristic for hydrologic cycle in the catchment that the share of seasonal sums of both the global radiation and temperature was nearly constant in 1983-2000. However, the seasonal sums of both the global radiation and temperature were changed considerably in 1983-2000. Similarly, the share of seasonal sums of both the rainfall and runoff was nearly constant in 1983-1991 and 1997-1999. An anomalous course of climate was registered in 1992-1996, manifested by a deviation on the double mass curve of the seasonal sums of rainfall and runoff. Stabilised elsewhere, the ratio of rainfall and runoff is changed during the vegetation seasons 1992-1996. Starting from the 1997 season, this ratio has obtained the value held before 1992. The reason of the 1992-1996 anomaly of hydrologic cycle in the experimental catchment had to be significant external phenomenon, most likely explosion of the Mount Pinatubo volcano in Philippines on June 15, 1991. and Hydrologic cycle in the Liz catchment is described with an anomaly in the vegetation seasons 1992- 1996. Experimental catchment Liz is located in the Šumava Mts. in the Czech Republic. The fully forested watershed is covered by mature spruce forest, and its basic characteristics are as follows: drainage area 0.99 km2 , mean discharge 0.01m3 s -1, runoff coefficient 0.38, mean annual air temperature 6.30 ºC, average slope 17 %, basin length 1.45 km, water course length 1.43 km, elevation 828-1074 m a.s.l., precipitation sum 851 mm year-1, and runoff depth 324 mm year-1. Air temperature, precipitation, global radiation, and discharge in the closing profile are measured in the catchment. It is characteristic for hydrologic cycle in the catchment that the share of seasonal sums of both the global radiation and temperature was nearly constant in 1983-2000. However, the seasonal sums of both the global radiation and temperature were changed considerably in 1983-2000. Similarly, the share of seasonal sums of both the rainfall and runoff was nearly constant in 1983-991 and 1997-1999. An anomalous course of climate was registered in 1992-1996, manifested by a deviation on the double mass curve of the seasonal sums of rainfall and runoff. Stabilised elsewhere, the ratio of rainfall and runoff is changed during the vegetation seasons 1992-1996. Starting from the 1997 season, this ratio has obtained the value held before 1992. The reason of the 1992-1996 anomaly of hydrologic cycle in the experimental catchment had to be significant external phenomenon, most likely explosion of the Mount Pinatubo volcano in Philippines on June 15, 1991.
The aim of this study is to understand the seasonalities of runoff and precipitation and their controls along two transects in Peru and one transect in Austria. The analysis is based on daily precipitation data at 111 and 61 stations in Peru and Austria, respectively, and daily discharge data at 51 and 110 stations. The maximum Pardé coefficient is used to quantify the strength of the seasonalities of monthly precipitation and runoff. Circular statistics are used to quantify the seasonalities of annual maximum daily precipitation and annual maximum daily runoff. The results suggest that much larger spatial variation in seasonality in Peru is because of the large diversity in climate and topography. In the dry Peruvian lowlands of the North, the strength of the monthly runoff seasonality is smaller than that of precipitation due to a relatively short rainy period from January to March, catchment storage and the effect of upstream runoff contributions that are more uniform within the year. In the Peruvian highlands in the South, the strength of the monthly runoff seasonality is greater than that of precipitation, or similar, due to relatively little annual precipitation and rather uniform evaporation within the year. In the Austrian transect, the strength of the runoff seasonality is greater than that of precipitation due to the influence of snowmelt in April to June. The strength of monthly regime of precipitation and runoff controls the concentration of floods and extreme precipitation in Peruvian transects. The regions with strong monthly seasonality of runoff have also extreme events concentrated along the same time of the year and the occurrence of floods is mainly controlled by the seasonality of precipitation. In Austria, the monthly runoff maxima and floods occur in the same season in the Alps. In the lowlands, the flood seasonality is controlled mainly by summer extreme precipitation and its interplay with larger soil moisture.
The analyses of precipitation and runoff data along topographic gradients in Peru and Austria showed that, overall, in Peru the spatial variation in seasonality is much larger than in Austria. This is because of the larger diversity in climate and topography.
In the paper there the questions of selection of representative period for the hydrological characteristics assessment are discussed. Also the characteristics of runoff and precipitation for the periods 1931-1980 and 1961-2000 are presented. The main components of water balance in Slovakia are the basis for comparison of both periods. The assessment of development of runoff condition during the last decades is presented. and V referáte sa diskutujú otázky výberu reprezentatívneho obdobia pre stanovenie hydrologických charakteristík. Ďalej sa uvádzajú charakteristiky odtoku a zrážok za obdobia 1931-1980 a 1961-2000. Na základe hodnotenia hlavných komponentov hydrologickej bilancie Slovenska sa obidve obdobia porovnávajú a opisuje sa vývoj odtokových pomerov ostatného obdobia.