Fog water represents an alternative, abundant and currently unexploited fresh water resource in the coastal Atacama Desert (~20°S). Here, the stratocumulus clouds meet the Coastal Cordillera, producing highly dynamic advective marine fog, a major feature of the local climate that provides water to a hyper-arid environment. One of the main issues that arises in harvesting fog water is our limited understanding of the spatial and inter-annual variability of fog clouds and their associated water content. Here we assess the role of regional-wide El Niño Southern Oscillation (ENSO) forcing on local inter-annual fog-water yields along the coast of Atacama. We contrast 17 years of continuous fog-water data, with local and regional atmospheric and oceanographic variables to determine the link between them and the inter-annual dynamics of fog in northern Chile. Sea surface temperature (SST) in ENSO zone 1 + 2 shows significant correlations with offshore and coastal Atacama SST, as well as with local low cloud cover and fog water yields, which go beyond the annual cycle beat, exposing a potential causal link and influence of ENSO on fog along the Atacama. On the inter-annual time scale, we found that when ENSO 3 + 4 zone SST, specifically during summer, overcome a > 1°C temperature threshold, they incite significantly higher summer fog water yields and explain 79% of the fog variability. Furthermore, satellite images displaying regional extent Sc cloud and fog presence during ENSO extremes reveal higher cloud abundance during El Niño at this latitude. However, 75% of the yearly fog water is collected during winter, and does not appear to be affected in a significant manner by Pacific oscillations. Thus, our results suggest that the utilization of fog as a fresh water resource may be sustainable in the future, regardless of ENSO-induced variability in the region.

RESUMENDurante el evento extremo "El Niño", ocurrido en agosto de 2015 en la costa de la región de Tarapacá, Desierto de Atacama, se registraron precipitaciones de 50 mm en el Oasis de Niebla de Alto Patache (promedio anual de 1 mm), activando la germinación de muchas de las especies presentes en el lugar. Tras el evento antes mencionado, se demarcaron transectos y se registró la presencia y dominancia de las especies de flora; se compararon los datos florísticos con los registros históricos del sitio y con la distribución de la niebla, medida entre el 2001 y 2002. Como resultado, se identificaron 42 especies, un 78% del total de flora conocida para el área, con un registro nuevo (Tiquilia sp.). El análisis de las especies, permitió identificar tres unidades de vegetación y se observó una mayor diversidad de especies en la zona con menor altitud del farellon costero.Palabras claves: Desierto de Atacama, Alto Patache, flora, vegetación, neblina. ABSTRACTDuring the extreme precipitation event related with "El Niño", which occurred in August 2015 on the coast of the Tarapaca region, Atacama Desert, rainfall of 50 mm was recorded at the Alto Patache Fog Oasis (annual average of 1 mm), activating germination of many species present on the site. After the event, transects were demarcated and the presence and dominance of vegetation was recorded. The floristic data identified was compared with historical records and related with the distribution of fog, measured between the years 2001 and 2002. Results show 42 species identified, 78% of all known plants in the area, with one new record (Tiquilia sp.). The floristic analysis allowed the identification of three vegetation units, and a greater diversity of species was observed in lower areas of the coastal mountain chain.

Durante el 9 agosto de 2015 (9A) (año El Niño Fuerte) se produjeron lluvias torrenciales anómalas que favorecieron el desarrollo de aluviones en el