Pablo Osses

The effects of climate and topography on soil physico-chemical and microbial parameters were studied along an extensive latitudinal climate gradient in the Coastal Cordillera of Chile (26° - 38°S). The study sites encompass arid (Pan de Azúcar), semiarid (Santa Gracia), mediterranean (La Campana) and humid (Nahuelbuta) climates and vegetation, ranging from arid desert, dominated by biological soil crusts (biocrusts), semiarid shrubland and mediterranean sclerophyllous forest, where biocrusts are present but do have a seasonal pattern to temperate-mixed forest, where biocrusts only occur as an early pioneering development stage after disturbance. All soils originate from granitic parent materials and show very strong differences in pedogenesis intensity and soil depth. Most of the investigated physical, chemical and microbiological soil properties showed distinct trends along the climate gradient. Further, abrupt changes between the arid northernmost study site and the other semi-ari...

<p>The Atacama desert is one of the most promising places on Earth for developing solar power energy due to its aridity, irradiation, and market conditions. However, the high levels of dust attenuate solar power production. This problem is solved by frequent cleaning of the solar panels, which requires a significant amount of water in one of the driest places in the world. Despite the drought condition, the fog and dew formed at the coastal zone of the desert arise as a complementary water source that can potentially be tapped. In this study, we assess the potential of atmospheric water for usage in four solar power plants. We conduct this assessment by combining a satellite-spatial analysis of fog and low cloud frequency, a thermodynamic vertical characterization of the marine boundary layer, and an observational analysis of fog and dew collection using different instruments. Our results reveal that fog and dew are a regular phenomenon in the solar power plants analyzed, being present between 3% and 20% of the year. Oceanic conditions control such phenomena through the inland advection of the marine boundary layer. This layer interacts with a complex topography characterized by natural corridors that allow fog and low clouds to penetrate farther inland. Our observations show that fog and dew are collected mainly during the night, with average rates between 0.1 and 0.2 L m<sup>-2</sup> day<sup>-1</sup>. Our research confirms that atmospheric water potential vastly exceeds the solar power plant water demand, demonstrating that atmospheric water is a reliable source for the industry.</p>

The rural economy is constituted of many economic activities as forest, fishing and of course agriculture, among others that are developed in nonurban areas. In this work the rural areas are analyzed from a spatial perspective (areal and georreferenced Information), in terms of density of population, distance to the centers of services and activities that are developed on them. The general objective is to quantify, characterize and hierarchize the rurality in the X Region of the Lakes – Chile, and to relate these levels to some developed economic activities. As specific objectives they are establish the density of population on a spatial resolution of 4.5 by 4.5 km, determine the levels of accessibility in terms of travel time for each density of population and characterize the economic activities and the relation of the income and level of poverty associated to the indicated spatial aspects. As work hypothesis subscribes that the size of the rural sector could be greater to the one...

Xi IRC4A CONFERENCE - PROCEEDINGS Actually, there are geographical methods for detecting the best places with high frequency of fog , techniques to study the potential for fog water collection, and large or massive systems for the collection of the water. A project funded ...

In the coastal Atacama Desert in Northern Chile plant growth is constrained to so-called ‘fog oases’ dominated by monospecific stands of the genus Tillandsia. Adapted to the hyperarid environmental conditions, these plants specialize on the foliar uptake of fog as main water and nutrient source. It is this characteristic that leads to distinctive macro- and micro-scale distribution patterns, reflecting complex geo-ecological gradients, mainly affected by the spatiotemporal occurrence of coastal fog respectively the South Pacific Stratocumulus clouds reaching inlands. The current work employs remote sensing, machine learning and spatial pattern/GIS analysis techniques to acquire detailed information on the presence and state of <i>Tillandsia spp.</i> in the Tarapacá region as a base to better understand the bioclimatic and topographic constraints determining the distribution patterns of <i>Tillandsia spp.</i> Spatial and spectral predictors extracted from Worl...

The hyperarid Atacama Desert coast receives scarce moisture inputs mainly from the Pacific Ocean in the form of marine advective fog. The collected moisture supports highly specialized ecosystems, where the bromeliad Tillandsia landbeckii is the dominant species. The fog and low clouds (FLCs) on which these ecosystems depend are affected in their interannual variability and spatial distribution by global phenomena, such as ENSO. Yet, there is a lack of understanding of how ENSO influences recent FLCs spatial changes and their interconnections and how these variations can affect existing Tillandsia stands. In this study, we analyze FLCs occurrence, its trends and the influence of ENSO on the interannual variations of FLCs presence by processing GOES satellite images (1995–2017). Our results show that ENSO exerts a significant influence over FLCs interannual variability in the Atacama at ~ 20°S. Linear regression analyses reveal a relation between ENSO3.4 anomalies and FLCs with oppos...

<p>The coastal regions of the Atacama Desert comprise some of the driest areas of the world, with average annual precipitation mostly less than 1 mm per year. It is in these environments where the ocean-atmosphere interconnected system determines the spatio-temporal dynamic of an advective coastal fog, providing moisture out stratocumulus clouds from the Pacific Ocean to an hyper-arid environment and allowing the development of fog ecosystems and high biodiversity along the Atacama coast.<br />Studies about fog has been done in this region since the middle of the 20th century. However, there is a high quality knowledge gap about spatio-temporal fog dynamics on a local scale and its interaction of climate variables with topography. The study on fog climatology and its variability will be the basis for the analysis of complex biosphere-atmosphere interactions, in which the local ecosystems can act as bio-indicators for fog water availability and climate change.<br />The study area is situated in the Chilean coastal desert of Atacama in the Tarapacá region (20° S), where a transect of seven climatological stations located between 518 m and 1,354 m altitude, from the coast to 10.7 km inland, records a high temporal (hourly/10-minutes) atmospheric data. The climate stations measurement it is based on Standard Fog Collectors (SFC) and a broad set of atmospherical variables that allows determine the relationship between the spatio-temporal variability of the fog and its driving parameters.<br />First results show a significant local intraannual fog variability with marked spatial differences in fog water collected and its atmospherical parameters along longitudinal and altitudinal gradient. The fog dynamic could provide a test bed for analyzing, assess and modeling biosphere-atmospheric interactions and relating them to meso-climate regimes.</p>

<p>The coastal Chilean Atacama Desert comprise some of the driest areas of the world with anual mean precipitation partly less than 1 mm/year, like in the Tarapacá region. It is in these environments, where fog plays a relevant role for local ecosystems, like the so called <em>Tillandsia</em> Lomas. These fog ecosystems contain <em>Tillandsia landbeckii</em> as an endemic species, which covers a vertical range of about 800 to 1,250 m, related to fog availability. The study area “Oyarbide” (20°29’ S, 70°03’ W) is situated inland desert, over a range of 300 m elevation where the advective and orographic fog penetrate far enough to reach the east border of the site at around 1,200 m.</p> <p>On local level, the understanding of the fog climate characteristics and variability is still poor as well as knowledge about the driving parameters, the temporal dynamics and spatial gradients. For this reason, various parameters of fog climate are analysed and characterised on the basis of a local station network in order to determine the local fog climatology.</p> <p>From 2016, several high quality climatological stations (Thies Clima) were installed in “Oyarbide”, located in a transect from ca. 1,160 m to ca. 1,350 m in a distance between 10.3 km to 10.7 km from the coast. The local network of climate stations is generating a high temporal and spatial acquisition of climatological data of standard fog water (2 m), air temperature & humidity (2 m), surface temperature (5 cm), wind speed & direction (10 m & 2 m), air pressure, global radiation, leaf wetness and dew every 10 minutes until nowadays. Additionally, ten mini fog collectors (Mini FCs) were installed at the beginning 2019, covering a surface of ca. 3 km<sup>2</sup>, generating a monthly data of ground fog water collected (50 cm).</p> <p>First spatio-temporal analyses of different parameters of the local fog climate will be presented. The results of the study show a seasonal, monthly and daily variability, with altitudinal and vertical differences and oscillation. The results will serve as input for the understanding of the fog variability into hyperarid zones.</p>

In the Atacama Desert, one of the driest places on earth, fog deposition plays an important role for the water balance and for the survival of vulnerable ecosystems. The eddy covariance method, previously applied for the quantification of fog deposition to forests in various parts of the world, was used for the first time to measure deposition of fog water

Alto Patache coastal fog oasis is a protected area located south of Iquique, Northern Chile, being presently in charge of the Atacama Desert Center (ADC) research group of the Pontificia Universidad Católica de Chile, since 1997. On 2007, the Chilean Government bestowed a piece of land stretch covering 1,114 hectares to ADC scientific group for scientific research, ecosystem protection and