Cambios en la cobertura de nieve y su relación con el caudal para la caracterización, monitoreo y gestión de las cuencas de montaña en los Andes extratropicales de Chile entre los 29° y 37°S utilizando teledetección

Central Chile (30°- 37° S), concentrates about 75% of the population of the country which translates into a huge demand for water. Much of the available water in this area comes from seasonal snow and glaciers located in the high mountain. In this context, climate change is positioned as a threat to water security through the decrease in rainfall and the acceleration of the melting of snows. It is necessary to have robust systems to monitor the spatial-temporal variability of snow patterns in order to quantify effects and map affected areas and to develop forecasting systems and prepare contingency plans. The present work establishes the relationship between snow cover and flow determining the spatio-temporal variability of subbasins of the extratropical Andes of Chile (29°- 37° S) between the years 2000-2020 using MODIS satellite images and climate variables through Google Earth Engine.The results account for the characterization of the hydrological regime and the seasonal pattern of the snow of the sub-basins studied, being those located in the central portion of the study area (30.5°- 35° S) of a snow regime, and at the edges (29° and 36° S) mixed regime. This configuration affects the annual flow dynamics where a lag period can be seen between the maximum continuous precipitation and the maximum flow rate. Likewise, there has been a constant decrease in snow coverduring the last 20 years being appreciable that in the central portion of the study area (that is, 33°- 35° S) this process occurs more severely. The experience gained from the analysis and the results of this work indicate the feasibility of using approximations associated with satellite remote sensing to estimate variations in the snow cover pattern and better characterize the hydrological regimes of basins with limited meteorological data to support water monitoring for the sustainability of the cryosphere and for the water security of the territories.Chile Central (30° - 37°S), concentra cerca del 75% de la población total del país, lo cual se traduce en una enorme demanda hídrica. Gran parte del agua disponible del área en cuestión proviene de la nieve estacional y los glaciares ubicados en la alta cordillera. En este contexto, el cambio climático se emplaza como una amenaza para la seguridad hídrica, mediante la disminución en las precipitaciones y la aceleración del derretimiento de las nieves. Se hace necesario contar con robustos sistemas de monitoreo de la variabilidad espacio temporal de los patrones de nieve de manera de poder cuantificar efectos y zonificar áreas afectadas para desarrollar sistemas de pronósticos y preparar planes de contingencia. El presente trabajo establece la relación entre cobertura nival y el caudal, determinando la variabilidad espaciotemporal entre el año 2000-2020 de subcuencas de los Andes extratropicales de Chile (29°-37°S), mediante imágenes satelitales MODIS y variables climáticas utilizando Google Earth Engine. Los resultados, dan cuenta a la caracterización del régimen hidrológico y el patrón estacional de la nieve de las subcuencas estudiadas, siendo de régimen nival las ubicadas en la porción central del área de estudio (30,5°-35° S), y las mixtas en los bordes (29° y 36° S). Esta configuración, repercute en la dinámica anual de los caudales en donde se aprecia un periodo de desfase entre el máximo de precipitación sólida y el máximo del caudal. Asimismo, se observó una disminución constante en la cobertura de nieves durante los últimos 20 años, siendo apreciable que en la porción central del área de estudio (i.e. 33° - 35°S) este proceso ocurre de forma más severa. La experiencia obtenida en función al análisis y resultados en este trabajo, indica la factibilidad de utilizar aproximaciones asociadas a la teledetección satelital a fin de estimar variaciones en el patrón de cobertura de nieve y caracterizar de mejor manera los regímenes hidrológicos de cuencas con datos meteorológicos limitados con el propósito de apoyar el monitoreo hídrico parala sustentabilidad de la criósfera y para la seguridad hídrica de los territorios

Short vs. long-distance avocado supply chains: Life cycle assessment Impact associated to transport and effect of fruit origin and supply conditions chain on primary and secondary metabolites

Avocado consumption and trade are increasing worldwide, with North America and Europe being the main importing regions. Spain is the major European avocado producer (90% of the production), yet it only supplies 10% of the market. Consequently, more than 90% of the avocados consumed in Europe are imported from overseas, mainly from Chile and Peru. In this work, the Life Cycle Assessment (LCA) impact associated with the transport of two avocado supply chains (short (Spanish) and long (Chilean)) and the effect of the fruit origin and distance of both chains on primary and secondary metabolites from harvest to edible ripeness were evaluated using a gas chromatography-mass spectrometry (GC-MS) and liquid chromatography coupled to diode array detection (LC-DAD) based metabolite analysis. The LCA transport impact of the fresh supply chain from production centers in Chile (Quillota) and Spain (Malaga), and then the distribution to several cities in Europe, suggested road export from Spain to European capitals to have the lowest impact (0.14 to 0.22 kg CO2 eq/kg of avocado). When export from Chile was considered, the option of oceanic freight to European ports closer to final destinations was clearly a better option (0.21 to 0.26 kg CO2 eq/kg) than via the Algeciras port in Spain followed by road transport to final destinations in European capitals (0.34 to 0.43 kg CO2 eq/kg), although the situation could be somewhat different if the avocados are transported from the destination ports in northern Europe to long-distance capitals in other European countries. Fruit origin had a significant impact on avocado primary and secondary metabolites. The conditions of the supply chain itself (10 d in cold storage in regular conditions vs. 30 d cold storage + controlled atmosphere conditions) largely influence the fate of some metabolites that certainly affect the pool of metabolites at edible ripeness. The long-assumed hypothesis that the longer the supply chain the more negative impact on nutritional and functional compounds might not hold in this case, as long as transport conditions are adequate in terms of temperature, atmosphere conditions, and time considering distance from origin to destination.This research was funded by Fondecyt Nº 1180303 and REDBIO0001 PCI from ANID (Chile) and for the RTI2018-099139-B-C21 from Ministry of Science and Innovation (Spain)—National Research Agency (MCIN/AEI/10.13039/501100011033) and by “ERDF A way of making Europe”, of the European Union. R. Pedreschi and E. Aguayo are thankful to the grant of Fundación Séneca (Murcia, Spain) through the “Jiménez de la Espada” Program of Visiting Researchers. This research was partially supported by the grant VRIEA-PUCV Nº 039.436/2020