Resumo

HERNANDEZ-DUARTE, Ana Guadalupe et al. Changes in snow cover and its relationship with flow for the characterization, monitoring and management of mountain basins in the extratropical Andes of Chile between 29° and 37°S using remote sensing. Bol. estud. geogr. [online]. 2021, n.116, pp.123-156.  Epub 25-Jun-2023. ISSN 2525-1813.  http://dx.doi.org/10.48162/rev.40.010.

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 sub-basins 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 cover during 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.

Palavras-chave : snow cover; mountain hydrology; extratropical Andes; remote sensing; Google Earth Engine.

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