Long-term variations in water balance components for Croatia
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In addition to air temperature at 2 m above ground, the following water balance components are considered: precipitation amount, potential and real evapotranspiration, surface runoff, recharge of water into the soil, loss of water from the soil, soil moisture content, and measured river discharge. Monthly air temperature and values of all water balance components (some of calculated using the Palmer method) have been considered for 24 weather stations across Croatia for the period 1951–2000, and for the Zagreb-Grič station for a much longer period, 1862–2000. The Sava River discharge for two hydrological stations (Zagreb and Županja) for the period 1931–2000 has also been used. Twenty-five year moving averages have been calculated from annual mean values and, – for air temperature only, a principal component analysis has been performed. We have found a long-term positive trend in air temperature, and potential and real evapotranspiration; and a negative trend in runoff (discharge) over almost the whole of Croatia, while the moving-average precipitation amounts show cyclical variation. No obvious trend for the recharge of water into the soil and its losses from the soil have been found, however, a negative trend in soil moisture content has been observed. The positive trends in air temperature and potential (real) evapotranspiration and the negative trends in soil moisture content and runoff (discharge) are consistent (to some degree) with recent global climate warming. This fact strengthens the importance of this study.
KeywordsSoil Moisture Content Precipitation Amount Negative Trend Potential Evapotranspiration Water Balance Component
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- Burroughs, W 2003Climate into the 21st centuryWorld Meteorological OrganisationGeneva240Google Scholar
- IPCC (2007) Contribution of Working Group I to the Fourth Assessment Report on climate change. 10-th Session of Working Group I of the IPCC, Paris, February 2007 (www.ipcc.ch)
- Lozan, JLGrassl, HHupfer, P eds. 2001Climate of the 21st century – changes and risksWissenschaf tliche Auswertungen & GEOHamburg448Google Scholar
- Oke, TR 1987Boundary layer climatesMethuenLondon435Google Scholar
- Palmer CW (1965) Meteorological drought. U.S. Department of Commerce, Washington, Research Paper No. 45, 58 ppGoogle Scholar
- Pandžić, K 1985Water balance on the Eastern Adriatic coastal regionPapers (Zagreb)202129Google Scholar
- Pandžić, K 1986Factor analysis of temperature field on a relatively small areaIdojaras90321331Google Scholar
- Penzar, B 1976Drought indices for Zagreb and their statistical forecast (in Croatian)Papers and Presentations (Zagreb)13158Google Scholar
- Penzar, B, Penzar, I, Juras, J, Marki, A 1992Brief review of the climatic fluctuations recorded in Zagreb between 1862 and 1990Geofizika95767Google Scholar
- Preisendorfer, RW 1988Principal component analysis in meteorology and oceanographyElsvierAmsterdam425Google Scholar
- Wilks, DS 2006Statistical methods in the atmospheric sciencesElsevierAmsterdam627Google Scholar