Untersuchungen zur Divergenz zwischen den Langzeittrends der realen Verdunstung von Schwarzbrache, Gras- und Kleeansaaten und der potenziellen Verdunstung im mitteldeutschen Raum als ein Beitrag zur Klimadiagnose

Abstract

Müller, J.; Böttcher, F.; Schmidt, M.; Zirnstein, A.: Analyses of divergences between seculartrends of actual evaporation and potential evaporation, based on ploughed land, grass and clover in thesemiarid area of Central Germany. – Hercynia N. F. 43 (2010): 177–188.In the present work, the actual evaporation and the potential evaporation according to the model of J.& G. Müller were analysed over a period of 48 years (from 1962 to 2009). These investigations arebased on grass and clover. The final results were added up to 3 months. The trend shows an increasingdivergence in each 2nd quarter during the period from 1962 to 2009. This information gives evidencefor the increasing drought and the limited accumulation of grass and clover biomass between April andJune. Ploughed land was also incorporated in the simulation to improve the spectrum of the soil layers.The investigations are based on measurements of the weather stations Gera-Leumnitz and Chemnitz.The measurements include air temperature, precipitation amount and sunshine duration over flood-plainclay and loess from 1962 to 2009. The results were compared with results of the weather station Halle-Kröllwitz. In Halle-Kröllwitz there was no decrease in the direction of evaporation for ploughed land.In addition to this, there was no decrease in the direction of evapotranspiration of grass and clover overa period of 48 years. Finally, there was an interesting result: According to the amount, the actual evapotranspirationof grass on loess was similar to the evapotranspiration of clover on flood-plain clay.Key words: climate-moisture-index, climate change, evaporation, evapotranspiration