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Data-Driven Approaches for Improved Evapotranspiration Modelling with Limited Data
Považanová, Barbora ; Čistý, Milan
This study uses data-driven methods to estimate FAO Penman-Monteith Reference Evapotranspiration (ETo) using only temperature data. Reference evapotranspiration, as an important variable for estimating actual evapotranspiration, is crucial in various water management tasks. However, some data for the Penman-Monteith equation is often unavailable. Thus, the need to use alternative methods emerges. The research shows DDM's effectiveness particularly when feature engineering was used. The study tested standard equations (Hargreaves Samani) and a proposed CatBOOST model with feature engineering to model ETo. The CatBOOST model achieved a higher R2 of 0.94 than the standard equations' R2 of 0.86. This result underscores DDM’s potential to refine evapotranspiration modelling for wide applications in water resource management, irrigation, and agriculture.
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Analysis of Spring Barley Actual Evapotranspiration
Pozníková, Gabriela ; Fischer, Milan ; Pohanková, Eva ; Žalud, Zdeněk ; Trnka, Miroslav
Evapotranspiration (ET) represents the main water-loss part of the water balance in agricultural landscape. The reliable quantification of the agricultural field ET is, however, still a challenge. To calculate ET, the Bowen ratio/energy balance (BREB) method was used in this study. It is based on measurements of the temperature and humidity gradients and radiation balance with the soil heat flux. Calculated ET was further used to quantify crop coefficient (Kc). Subsequently, we analysed the crop coefficient of spring barley during one growing season since 7th May 2013 to 30th July 2013. We used the data obtained above 1-ha spring barley field in Bystřice nad Pernštejnem, Czech Republic. In particular, we investigated how Kc correlates to climatic conditions as rainfall and soil humidity and how it reflects Plant Area Index (PAI) during the year during different parts of growing season. The cumulative ET of spring barley was 228.6 mm per investigated period. For reference evapotranspiration (ETo) two different approaches were used. Typically, a reference grass cover 0.12 m high standard for Europe. On the other hand, in the USA it is common to use also alfalfa (0.50 m high). ETo of grass was 296.3 mm and ETo of alfalfa was 351.4 mm. Maximum Plant Area Index occurred in June and its value was 4.1. Mean Kc in May was 1.17 for reference grass and 1.03 for alfalfa. Similarly in June, Kc was equal to 1.16 (grass) and 1.03 (alfalfa). Finally in July, for reference grass Kc was 0.55 and 0.48 for alfalfa. The decline at the end of the growing season was caused by dry weather and ripe stage of spring barley.
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