Occurrence of Dry and Wet Periods in Altitudinal Vegetation Stages of West Carpathians in Slovakia: Time-Series Analysis

Transcription

1 Occurrence of Dry and Wet Periods in Altitudinal Vegetation Stages of West Carpathians in Slovakia: Time-Series Analysis J. Hrvoľ,, J. J Škvarenina,, J. J Tomlain, J. Škvareninová,, P. Nejedlík

2 Vegetation stages /Zlatnik,, 1976/ 1st Oak 2nd Beech-Oak 3rd Oak-beech 4th Beech 5th Fir-beech 6th Spruce- fir-beech 7th Spruce 7th Spruce & 8th Mountain pine 5 % of terr

3 Vegetation stages. Oak. Beech-oak. Oak-beech. Beech. Fir-beech. Spruce-beeh-fir. Spruce. Dwarf pine. Alluvial communities

4 Where are we? Area

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7 50000km 2, mean altitude 450 m a.s.l., 41% of territora covered by forests

8 Stations

9 Drought Natural Climate Variability T I M E D u r a t i o n Precipitation deficiency High temp., high winds, (amount, intensity, low relative humidity, timing) greater sunshine, less cloud cover Reduced infiltration, runoff, deep percolation, and ground water Increased evaporation recharge and transpiration Soil water deficiency Plant water stress, reduced biomass and yield Reduced streamflow, inflow to reservoirs, lakes and ponds; reduced wetlands, wildlife habitat Meterological Drought Agricultural Drought Hydrological Drought Economic Impacts Social Impacts Environmental Impacts Socioeconomicenvironmental Drought

10 Methodology Evaluated parameters /annual and seasonal values/: -Precipitation, P [mm] -Potential evapotranspiration, E 0 [mm] -Actual evapotranspiration, E [mm] -Relative evapotranspiration, E/E 0 [%] -Drought index, E 0 /P [-]

11 Definitions E 0 maximal possible evapotranspiration under the given energy condition /no water shortage/ E the evapotranspirarion under the real energy and water supply conditions E = E o.w/w o W - water stored in the upper soil layer of 1 m depth W o - the critical value above which E equals E o

12 Average annual values of precipitation (P), potential (Eo( Eo), actual evapotranspiration (E), drought index (Eo( Eo/P) and relative evapotranspiration (E/Eo Eo) ) at chosen localities of Slovakia for in Meteorological station H [m a.s.l.] P [mm] Eo [mm] E [mm] E/Eo [%] Eo/P [ - ] Vegetation stage Hurbanovo ,44 1 st Oak Myjava ,96 2 nd Beech-Oak Kamenica n. C ,92 3 rd Oak-beech Plaveč ,78 4 th Beech Červený Kláštor ,69 5 th Fir-beech Oravská Lesná ,42 6 th Spruce- fir-beech Tatranská Javorina ,35 7 th Spruce Štrbské Pleso ,45 7 th Spruce & 8 th Mountain pine

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14 Annual trend analysis ( ) of E/Eo Eo and (Eo/P). Probability level *p* < 0.1, **p < 0.05, ***p < 0.01, ****p < 0.001, n.s.. not significant Meteorological station E/Eo = f (years) Trend Eo/P = f (years) Trend Hurbanovo ** aridity *** aridity Myjava ** aridity n.s. - Kamenica n. C. n.s. - n.s. - Plaveč **** humidity **** humidity Červený Kláštor * humidity ** humidity Oravská Lesná n.s. - n.s. - Tatranská Javorina n.s. - **** humidity Strbske Pleso n.s. - * humidity

15 The dependence of relative evapotranspiration annual values (E/Eo Eo) on altidude [m a.s.l.].] in Slovakia in /logaritmic scale/ E/Eo [%] y = Ln(x) R 2 = altitude [m]

16 The dependence of drought index annual values (Eo( Eo/P) on altidude [m a.s.l.].] in Slovakia in /logarithmic logarithmic scale/ Eo/P y = Ln(x) R 2 = altitude [m]

17 The course of annual values of (E/Eo Eo) in Hurbanovo in linear trend and polynomial of 3rd order E/Eo [%] y = x x x - 1E+06 R 2 = y = x R 2 = year

18 The course of annual values of (Eo/P) in Hurbanovo in linear trend and polynomial trend of 3rd order Eo/P y = x R 2 = y = 3E-06x x x R 2 = year

19 The course of annual values of (E/Eo Eo) in Plaveč in linear trend and polynomial of 3rd order E/Eo [%] y = x R 2 = y = x x x + 2E+06 R 2 = year

20 The course of annual values of (Eo/P) in Plaveč in linear trend and polynomial trend of 3rd order Eo/P y = x R 2 = y = 5E-06x x x R 2 = year

21 Conclusions - Relative evapotranspiration and drought index, were used to characterise the energetic and humidity conditions of Slovakia There are two different climatic zones /temperate and boreal/ The relative evapotranspiration shows values as from 97 % in the northern mountainous regions, to 58 % in the Danubian lowland. A significant increase in the severity of drought was identified only in the Danube Lowland (1st Oak vegetation stage) and in Zahorská Lowland (2nd Beech-Oak vegetation stage); a significant trend of increasing humidity in mountains and in the northern part of East Slovakia.