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Evaporation in Mediterranean conditions: Estimations based on isotopic approaches at the watershed scale
Author(s) -
Mattei Alexandra,
Huneau Frédéric,
Garel Emilie,
Santoni Sébastien,
Vystavna Yuliya
Publication year - 2021
Publication title -
hydrological processes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.222
H-Index - 161
eISSN - 1099-1085
pISSN - 0885-6087
DOI - 10.1002/hyp.14085
Subject(s) - environmental science , mediterranean climate , evaporation , seasonality , mediterranean basin , watershed , hydrology (agriculture) , precipitation , stable isotope ratio , drainage basin , isotope analysis , streamflow , potential evaporation , water balance , atmospheric sciences , geology , ecology , meteorology , geography , oceanography , physics , geotechnical engineering , cartography , quantum mechanics , machine learning , computer science , biology
In Mediterranean regions, the marked climatic seasonality and uneven precipitation distribution complicate the application of isotope mass balances to obtain meaningful basin‐wide annual average evaporation rates. In the present study, a mass balance approach carried out on the Tavignanu River watershed in Corsica (France), showed unrealistic evaporation rate estimates: 10% for 2017–2018 and 1% for 2018–2019. This suggests that not only does evaporation alter the seasonal isotopic composition in the river, but that there is complex variability of the dominant water reservoirs contributing to the streamflow. Therefore, we propose a modified mass balance approach, including monthly quantifications of different water sources contributing to the river discharge. This allows the discrimination of isotopic variation occurring by evaporation from that originating by mixing processes. By applying this modified approach, we estimated evaporation rates on the Tavignanu River watershed that were in good agreement with results obtained by hydrological modelling: 40% for 2017–2018 and 46% for 2018–2019, respectively. An uncertainty analysis showed that evaporation rates obtained with the modified isotopic approach are close to those obtained with the non‐modified approach. Therefore, we recommend using this modified isotope mass balance approach to estimate evaporation rates in such regions as the Mediterranean with high seasonality in hydrological processes.