Variation of reference evapotranspiration in the central region of Argentina between 1941 and 2010

• The influence of the driving variables on ETo were analyzed in a grid scheme.
• First, the linear relationship of each atmospheric variable with ETo was analyzed.
• Then, the time trend of the controlling variables was assessed.
• No variable shown significant change considering both the relation with ETo and its own trend.
• The variation of ETo resulted not significant in most of the region.

Study regionChanges in reference evapotranspiration (ETo) may have important consequences for agricultural suitability in the central region of Argentina. Annual ETo variation was assessed, in terms of both territory and time, for the 7 decades between 1941 and 2010, analyzing the behavior of the 4 atmospheric variables which determine it: temperature, vapor pressure, wind speed and cloud cover.Study focusThe influence of each variable on ETo was evaluated from a multiple regression model and a simple correlation analysis, using climate data from the observation network, and repeating this analysis using interpolated variables. In this grid scheme, linear relationships were determined between ETo and the different key atmospheric variables, plus precipitation (PP), and the t test was applied to establish the statistically significant sectors (P < 0.1). Then, those areas with a significant trend change (P < 0.1) were determined by the Mann–Kendall test. Finally, the interception of the grids was performed to establish their joint occurrence.New hydrological insights for the regionMost of the region analyzed (>91%) presents a non-significant variation of ETo over time, with a mostly non-significant change of each driving variable, regarding both its relationship with ETo and its own trend of change. The beneficial change in agricultural suitability reported for this water-limited region was found to be produced almost exclusively by increasing PP.

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