Přednáška o výparu
Václav Šípek
Zdravím všechny,
chtěl bych vás pozvat na přednášku kolegy z TU Dresden, která se bude konat ve čtvrtek 5. října od 9.00 na Ústavu pro hydrodynamiku (50.1158489N, 14.3913589E). Přednáška se bude týkat stanovení výparu a cyklu skleníkových plynů na volné vodní hladině (název a krátká anotace přiložena na konci mailu).
Prosím potvrďte svou případnou účast na můj mail, ať víme, s kolika lidmi máme počítat.
Přeju pěkný den,
Vašek
What do we actually know about evaporation and greenhouse gas emissions from inland waters?
by Dr. Uwe Spank
Chair of Meteorology, Faculty of Environmental Sciences, Technische Universität Dresden, Tharandt, Germany
Keywords: carbon dioxide and methane emissions, eddy covariance, lakes and reservoirs, mass and energy fluxes, micrometeorological observations
The correct quantification of the mass and energy exchange between inland waters and the atmosphere is of great importance for water management. We have monitored and studied the mass and energy exchange at the Bautzen reservoir (Germany), which is approx. 130 km northern of Prague. The test site can be assessed as a representative sample for typical Mid-European non-mountainous lakes. A floating outdoor laboratory equipped with an eddy covariance measurement system and series of further meteorological, hydro-chemical, and hydro-physical sensors have been used for continuous measurements.
The results revealed that standard assumption for evaporation rates, carbon dioxide fluxes and methane emission of inland waters need to be revised. The evaporation of an inland water is much more complex than it is suggested in the majority of textbooks and the occurring evaporation in the centre of a water is much lower than the evaporation of a well water supplied vegetated terrestrial site. Put very simply, it can be said that an inland water behaves such as an oasis in a desert and that the total evaporation of a water is determined disproportionately by the evaporation at the shoreline, in the reed belt and in surrounding riparian forests. The measured carbon dioxide fluxes have shown an enormous short- and long-term variability including changes of flux direction. The methane emissions in the centre of this eutrophic reservoir are not negligible, but they are clearly below the emissions of swamps and wetlands. Methane oxidation in aerobic water layers is therefore an important process and important for the greenhouse gas balance of a water body. Thus, measures to improve water quality are desirable not only from a hydrological but also from a climate protection perspective.
-- RNDr. Václav Šípek, Ph.D. Tel: +420 233109028 E-mail: si...@ih.cas.cz Ústav pro hydrodynamiku Akademie věd České republiky Pod Paťankou 30/5 166 12 Praha 6 www.ih.cas.cz Institute of Hydrodynamics Czech Academy of Sciences Pod Patankou 30/5 166 12 Prague 6 Czech Republic www.ih.cas.cz/en