Browsing by Author "Vila-Guerau de Arellano, Jordi"

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    Characterizing the influence of the marine stratocumulus cloud on the land fog at the Atacama Desert
    (2018) Lobos Roco, Felipe; Vila-Guerau de Arellano, Jordi; Pedruzo-Bagazgoitia, Xabier
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    Multi-scale temporal analysis of evaporation on a saline lake in the Atacama Desert
    (2022) Lobos Roco, Felipe Andres; Hartogensis, Oscar; Suarez Poch, Francisco Ignacio; Huerta-Viso, Ariadna; Benedict, Imme; de la Fuente, Alberto; Vila-Guerau de Arellano, Jordi; CEDEUS (Chile)
    We investigate how evaporation changes depending on the scales in the Altiplano region of the Atacama Desert. More specifically, we focus on the temporal evolution from the climatological to the sub-diurnal scales on a high-altitude saline lake ecosystem. We analyze the evaporation trends over 70 years (1950–2020) at a high-spatial resolution. The method is based on the downscaling of 30 km ERA5 reanalysis data at hourly resolution 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 (EC) 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 significantly influences the saline lake surface spatial changes. From an interannual scale perspective, evaporation increased by 2.1 mm yr−1 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 %.
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    Observation-driven model for calculating water-harvesting potential from advective fog in (semi-)arid coastal regions
    (COPERNICUS GESELLSCHAFT MBH, 2025) Lobos Roco, Felipe Andrés; Vila-Guerau de Arellano, Jordi; Del Rio López, Camilo
    Motivated by the need to find complementary water sources in (semi-)arid regions, we develop and assess an observation-driven model to calculate fog-harvesting water potential. We aim to integrate this model with routine meteorological data collected under complex meteorological and topographic conditions to characterize the advective fog phenomenon. Based on the mass balance principle, the Advective fog Model for (semi-)Arid Regions Under climate change (AMARU) offers insights into fog-water-harvesting volumes across temporal and spatial domains. The model is based on a simple thermodynamic approach to calculate the dependence of the liquid water content (rl) on height. Based on climatological fog collection records, we introduce an empirical efficiency coefficient. When combined with rl, this coefficient facilitates the estimation of fog-harvesting volumes (L m-2). AMARU's outputs are validated against in situ observations collected over Chile's coastal (semi-)arid regions at various elevations and during various years (2018-2023). The model's representations of the seasonal cycle of fog harvesting follow observations, with errors of similar to 10 %. The model satisfactorily estimates the maximum rl (similar to 0.8 g kg-1) available for fog harvesting in the vertical column. To assess spatial variability, we combine the model with satellite-retrieved data, enabling the mapping of fog-harvesting potential along the Atacama coast. Our approach enables the application of the combined observation-AMARU model to other (semi-)arid regions worldwide that share similar conditions. Through the quantification of fog harvesting, our model contributes to water planning, ecosystem delimitation efforts, and the study of the climatological evolution of cloud water, among others.