THE STUDY OF POTENTIAL EVAPOTRANSPIRATION IN THE BANAT PLAIN IN 1897-2011 PUBLISHEDLaura I. SMULEAC, Silvica ONCIA, Anisoara IENCIU
The present study of potential evapotranspiration has taken into consideration a priority issue confronting our entire planet: global climate changes. This phenomenon can be revealed only through long-term monitoring. Consequently, for convincing results, the study considered all the data about the monthly temperatures that are recorded at Timisoara Weather Station, as this station has the oldest records in the Banat Plain. The studied period covers 114 years, from 1897 to 2011; unfortunately, the records between 1917 and 1920 are missing. Potential evapotranspiration is calculated with the Thornthwaite method, as this fits our country’s conditions best; however, for the water use calculation, it is necessary to determine the coefficients for each plant culture. The results were interpreted and systematised with the Bravais-Pearson correlation coefficient and linear regression. The study has concluded that annual potential evapotranspiration has a slightly increasing trend that is explained by the high temperatures of the past years that have exceeded the multiannual mean. Consequently, maximum evapotranspiration, 840.2 mm, was reached in the agricultural year 2008-2009, which caused a humidity deficit of 339.2 mm. The 1975-1976 agricultural year had the lowest value of evapotranspiration: 617.4 mm. Surprisingly, in the same year, the precipitations did not cover the plant water use, leading to a deficit of 117.2 mm. As far as evapotranspiration in the vegetation period is concerned, a much stronger increasing trend is observed than in the case of the annual trend. The maximum calculated value was 728.3 mm in the 2008-2009 agricultural year, accounting for 86.68% of annual evapotranspiration. In this vegetation period, the humidity deficit was also high - 464.3 mm. The minim, 532 mm, was recorded in the 1977-1978 agricultural year, which still had a 136.4 mm humidity deficit. On summing up the results, we have discovered that Banat is undergoing a process of transformation from the climatic viewpoint. The transformation is both thermal, as a result of its increased values in the past years, and pluviometric, caused by decreased rainfalls that no longer cover the plant water use. The present paper is a reference and original study, given the long period of time that was analysed - 114 years.
potential evapotranspiration, climate changes, temperature