Browsing by Author "Del Rio López, Camilo"

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    Remote sensing based mapping of Tillandsia fields-A semi-automatic detection approach in the hyperarid coastal Atacama Desert, northern Chile
    (2022) Mikulane, Signe; Siegmund, Alexander; Del Rio López, Camilo; Koch, Marcus A.; Osses Mc Intyre, Pablo Eugenio; García Barriga, Juan Luis
    Unique fog ecosystems that occur inland along the Chilean coastal desert are dominated by Tillandsia landbeckii. The average annual precipitation in this hyperarid area lies below 1 mm per year. Tillandsia are specialized in the foliar uptake of fog as a main source of water. The detailed mapping of the distribution of Tillandsia is lacking, making it difficult to understand their geo-ecological niche and to determine the impacts that climate change may have on this species. The objective of this study is to create a detailed spatial distribution of Tillandsia in the Atacama Desert in northern Chile based on remote sensing semi-automatic detection process. For this purpose, high-resolution WorldView-3 optical satellite data has been acquired. The extraction of Tillandsia was done with ENVI Deep Learning tools. As a result, a map of Tillandsia has been created. Several fields were found between Cerro Huantajaya in the north and Cerro Soronal in the south in the study area between 800 and 1300 m a.s.l. For validation purposes ground truth data has been used. The overall accuracy of this classification is 92.02%. The results can be used as a basis for geo-ecological niche modeling, further monitoring and for the development of conservation strategies.
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    Synoptic control of the spatiotemporal variability of fog and low clouds under ENSO phenomena along the Chilean coast (17°-36° S)
    (2024) Espinoza Escobedo, Vicente Patricio; Lobos Roco, Felipe Andrés; Del Rio López, Camilo
    The northern and central coasts of Chile have an extensive semi-permanent layer of stratocumulus clouds that produce fog on land, a crucial resource for water-stressed areas. This study examines the spatio-temporal variability of fog and low clouds (FLC) across four climatic zones (17°S-36°S) characterized by arid conditions. Our analysis aims to elucidate the relationship between FLC patterns and the El Niño-Southern Oscillation (ENSO) phenomenon based on 25 years (1998–2022) of GOES satellite images. The variability of FLC shows a marked, although spatially asymmetric, seasonal cycle, with a subtle positive trend in the long-term. Our results suggest that the presence of FLC is controlled by the strength of the thermal inversion (correlation coefficient, r = 0.7), which, in turn, depends on the sea surface temperature (SST) and the subsidence. Specifically, FLC patterns are controlled by SST in the north (r = −0.9) and by subsidence intensity in the south (r = 0.9). Furthermore, our analysis indicates a potential link between ENSO and FLC, which alters the SST-subsidence equilibrium. At 20°S, warm phases of ENSO lead to increased FLC during the summer and decreased FLC during the winter. Conversely, at 30°S, warm phases result in decreased FLC during the summer and increased FLC during the winter. However, during cold phases, this trend is reversed. At 20°S, FLC decreases in summer and increases in winter, while at 30°S, FLC increases in summer and decreases in winter. In summary, our study offers a novel perspective on understanding the large-scale dynamics associated with FLC frequency along the central and northern coasts of Chile, including FLC underlying mechanisms and the long-term influence exerted by ENSO on the phenomenon.