Articles | Volume 374
https://doi.org/10.5194/piahs-374-35-2016
https://doi.org/10.5194/piahs-374-35-2016
17 Oct 2016
 | 17 Oct 2016

Rainfall as proxy for evapotranspiration predictions

Bruno Collischonn and Walter Collischonn

Abstract. In this work, we evaluated the relationship between evapotranspiration and precipitation, based on the data recently made available by the Brazilian Meteorological Institute. ETP tend to be lower in rainy periods and vice-versa. This relationship was assessed both in physical and statistical ways, identifying the contribution of each explaining variable of ETP. We derived regression equations between monthly rainfall and ETP, which can be useful in studies where ETP time series are not available, such as reservoir design, irrigation management and flow forecast.

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Short summary
Hydrometerologial data in Brazil is becoming increasingly more accessible in recent years, but data gaps still exist in many regions. In our work, we tested some statistical ways to explore the existing data and fill gaps in evaporation estimates, based on the assumption that evaporation and precipitation are inversely related. This could be useful for extending evaporation series into the past, for example for hydropower reservoir planning and flow forecast.