Preprints
https://doi.org/10.5194/acp-2020-1300
https://doi.org/10.5194/acp-2020-1300

  22 Feb 2021

22 Feb 2021

Review status: a revised version of this preprint was accepted for the journal ACP and is expected to appear here in due course.

Local evaporation controlled by regional atmospheric circulation in the Altiplano of the Atacama Desert

Felipe Lobos-Roco1,2, Oscar Hartogensis1, Jordi Vilà-Guerau de Arellano1, Alberto de la Fuente3, Ricardo Muñoz4, José Rutllant4,5, and Francisco Suárez2,6,7 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
  • 3Department of Civil Engineering, Universidad de Chile, Santiago, Chile
  • 4Department of Geophysics, Universidad de Chile, Santiago, Chile
  • 5Centro de Estudios Avanzados en Zonas Aridas, La Serena, Chile
  • 6Centro de Desarrollo Urbano Sustentable (CEDEUS), Santiago Chile
  • 7Centro de Excelencia en Geotermia de los Andes (CEGA), Santiago Chile

Abstract. We investigate the influence of regional atmospheric circulation on the evaporation of a saline lake in the Altiplano region of the Atacama Desert. For that, we conducted a field experiment in the Salar del Huasco (SDH) basin (135 km east of the Pacific Ocean), in November 2018. The measurements were based on surface energy balance (SEB) stations and airborne observations. Additionally, we simulate the meteorological conditions on a regional scale using the Weather Research and Forecasting model. Our findings show two evaporation regimes: (1) a morning regime controlled by local conditions, in which SEB is dominated by the ground heat flux (~0.5 of net radiation), very low evaporation (LvE < 30 W m−2) and wind speed < 1 m s−1; and (2) an afternoon regime controlled by regional-scale forcing that leads to a sudden increase in wind speed (> 15 m s−1) and a jump in evaporation to > 500 W m−2. While in the morning evaporation is limited by very low turbulence (u*~0.1 m s−1), in the afternoon strong winds (u*~0.65 m s−1) enhance the mechanical turbulence, increasing the evaporation. We find that the strong winds in addition to the locally available radiative energy are the principal drivers of evaporation. These winds are the result of a diurnal cyclic circulation between the Pacific Ocean and the Atacama Desert. Finally, we quantify the advection and entrainment of free-tropospheric air masses driven by boundary-layer development. Our research contributes to extend our understanding of evaporation drivers in arid regions and how large-scale processes affect directly local ones.

Felipe Lobos-Roco et al.

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on acp-2020-1300', Anonymous Referee #2, 23 Mar 2021
    • AC1: 'Reply on RC1', Felipe Lobos Roco, 27 Mar 2021
  • RC2: 'Comment on acp-2020-1300', Anonymous Referee #1, 04 Apr 2021
    • AC2: 'Reply on RC2', Felipe Lobos Roco, 05 Apr 2021

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on acp-2020-1300', Anonymous Referee #2, 23 Mar 2021
    • AC1: 'Reply on RC1', Felipe Lobos Roco, 27 Mar 2021
  • RC2: 'Comment on acp-2020-1300', Anonymous Referee #1, 04 Apr 2021
    • AC2: 'Reply on RC2', Felipe Lobos Roco, 05 Apr 2021

Felipe Lobos-Roco et al.

Data sets

Dataset of Local evaporation controlled by regional atmospheric circulation in the Altiplano of the Atacama Desert Felipe Lobos Roco, Oscar Hartogensis, Jordi Vila, Alberto de la Fuente, and Francisco Suarez https://doi.org/10.17632/c5s6zk2rmz.2

Felipe Lobos-Roco et al.

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Latest update: 05 May 2021
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Short summary
We investigate the influence of regional atmospheric circulation on the evaporation of a saline lake in the Altiplano region of the Atacama Desert through a field experiment and regional modeling. Our results show that evaporation is controlled by two regimes: (1) in the morning by local conditions with low evaporation rates and low wind speed, and (2) in the afternoon with high evaporation rates and high wind speed. Afternoon winds are connected to the regional P. Ocean-Andes flow.
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