11 Feb 2022
11 Feb 2022
Status: this preprint is currently under review for the journal HESS.

Multi-scale temporal analysis of evaporation on a saline lake in the Atacama Desert

Felipe Lobos-Roco1,2, Oscar Hartogensis1, Francisco Suárez2,3,4, Ariadna Huerta-Viso1, Imme Benedict1, Alberto de la Fuente5, and Jordi Vilà-Guerau de Arellano1 Felipe Lobos-Roco et al.
  • 1Meteorology and Air Quality, Wageningen University, Wageningen, The Netherlands
  • 2Department of Hydraulic and Environmental Engineering, Pontificia Universidad Católica de Chile, Santiago Chile
  • 3Centro de Desarrollo Urbano Sustentable (CEDEUS), Santiago Chile
  • 4Centro de Excelencia en Geotermia de los Andes (CEGA), Santiago Chile
  • 5Department of Civil Engineering, Universidad de Chile, Santiago, Chile

Abstract. We investigate how evaporation changes depending on the scales in the Altiplano region of the Atacama Desert. More specifically, the temporal evolution from the climatological to the sub-diurnal scales on a high-altitude saline lake ecosystem. We analyse the evaporation trends over 70 years (1950–2020) at a high-spatial resolution. The method is based on the downscaling of 30-km hourly resolution ERA5 reanalysis data to 0.1-km spatial resolution data, using artificial neural networks to analyze the main drivers of evaporation. To this end, we use the Penman open water evaporation equation, modified to compensate for the energy balance non-closure and the ice cover formation on the lake during the night. Our estimation of the hourly climatology of evaporation shows a consistent agreement with eddy-covariance measurements and reveals that evaporation is controlled by different drivers depending on the time scale. At the sub-diurnal scale, mechanical turbulence is the primary driver of evaporation, and at this scale, it is not radiation-limited. At the seasonal scale, more than 70 % of the evaporation variability is explained by the radiative contribution term. At the same scale, and using a large-scale moisture tracking model, we identify the main sources of moisture to the Chilean Altiplano. In all cases, our regime of precipitation is controlled by large-scale weather patterns closely linked to climatological fluctuations. Moreover, seasonal evaporation influences significantly the saline lake surface spatial changes. From an interannual scale perspective, evaporation increased by 2.1 mm per year during the entire study period, according to global temperature increases. Finally, we find that yearly evaporation depends on the El Niño Southern Oscillation (ENSO), where warm and cool ENSO phases are associated with higher evaporation and precipitation rates, respectively. Our results show that warm ENSO phases increase evaporation rates by 15 %, whereas cold phases decrease it by 2 %.

Felipe Lobos-Roco et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on hess-2022-20', Anonymous Referee #1, 04 Mar 2022
    • AC1: 'Reply on RC1', Felipe Lobos Roco, 24 Mar 2022
  • RC2: 'Comment on hess-2022-20', Stephanie Kampf, 13 Mar 2022
    • AC2: 'Reply on RC2', Felipe Lobos Roco, 24 Mar 2022

Felipe Lobos-Roco et al.

Felipe Lobos-Roco et al.


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Short summary
This research brings a multi-scale temporal analysis of evaporation in a saline lake of the Atacama Desert. Our findings reveal that evaporation is controlled differently depending on the time scale. Evaporation is controlled sub-diurnally by wind speed, regulated seasonally by radiation, and modulated interannually by the ENSO. Our research extends our understanding of evaporation, contributing to improving the climate change assessment and efficiency in water management in arid regions.