The estimation of evapotranspiration using the meteorological data from Němčice station

B.Sc. Michael Opare Asare, BSc

Master's thesis

Abstract:

Evapotranspiration is a physical process, which remains very difficult if not impossible to measure directly. In the absence of direct measurements, calculations based on empirical or theoretical equations become quite important. This study evaluates and compares five empirical evapotranspiration models and their performance in water balance studies by using meteorological data from the Nemcice station in Czech Republic from April - October. Of the five models evaluated, three models calculate potential evapotranspiration. One of the three potential evapotranspiration models belong to the temperature-based category, i.e. the TUC model, and the other two belong to the radiation-based category, i.e. the Priestley-Taylor model (PT) and the Penman-Monteith model (PM). Two of the models are used for estimating actual evapotranspiration directly using the complementary relationship approach, i.e. the advection-aridity (AA) model of Brutsaert and Stricker, and the GG model of Granger and Gray. When the models were, bench marked with Evaporation values, PM model shows accurate deterministic behavior with little randomness followed by TUC model and finally the PT model. RMSE, MAE, MSE and ME are used for model accuracy (error estimation). The results show that for the calculation of actual evapotranspiration, the GG model (RMSE= 2.04) performed better than the AA model (RMSE= 2.75) in almost all the months. In estimating the potential evapotranspiration, temperature-based methods (Penman Monteith; RMSE=3.87 and TUC models RMSE= 2.10) performed better than radiation method (Priestley-Taylor RMSE=1.98) in terms of deterministic movement and estimates. The above-mentioned research is of great importance in full understanding of Evaporation, Actual and Potential Evapotranspiration processes, of predictability on different time scales and the water cycle character under climate change condition.

Keywords

Potential evapotranspiration, pan evaoporation, Actual evapotranspiration

Jazyk práce: English

Datum vytvoření / odevzdání či podání práce: 18. 4. 2017

Obhajoba závěrečné práce

• Vedúci: doc. Ing. Petr Máca, Ph.D.
• Oponent: Jiří Pavlásek, Ph.D.

Czech University of Life Sciences Prague

Faculty of Environmental Sciences

Master programme / odbor:
Landscape Engineering / Environmental Modelling