Snow cover dynamics in Andean watersheds of Chile (32.0–39.5° S) during the years 2000–2016
Andean watersheds present important snowfall accumulation mainly during the winter, which melts during the spring and part of the summer. The effect of snowmelt on the water balance can be critical to sustain agriculture activities, hydropower generation, urban water supplies and wildlife. In Ch...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-10-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://www.hydrol-earth-syst-sci.net/21/5111/2017/hess-21-5111-2017.pdf |
| Summary: | Andean watersheds present important snowfall accumulation mainly during the
winter, which melts during the spring and part of the summer. The effect of
snowmelt on the water balance can be critical to sustain agriculture
activities, hydropower generation, urban water supplies and wildlife. In
Chile, 25 % of the territory between the region of Valparaiso and
Araucanía comprises areas where snow precipitation occurs. As in many
other difficult-to-access regions of the world, there is a lack of
hydrological data of the Chilean Andes related to discharge, snow courses,
and snow depths, which complicates the analysis of important hydrological
processes (e.g. water availability). Remote sensing provides a promising
opportunity to enhance the assessment and monitoring of the spatial and
temporal variability of snow characteristics, such as the snow cover area
(SCA) and snow cover dynamic (SCD). With regards to the foregoing questions,
the objective of the study is to evaluate the spatiotemporal dynamics of the
SCA at five watersheds (Aconcagua, Rapel, Maule, Biobío and Toltén)
located in the Chilean Andes, between latitude 32.0 and 39.5° S, and
to analyse its relationship with the precipitation regime/pattern and
El Niño–Southern Oscillation (ENSO) events. Those watersheds were chosen
because of their importance in terms of their number of inhabitants, and
economic activities depending on water resources. The SCA area was obtained
from MOD10A2 for the period 2000–2016, and the SCD was analysed through a
number of statistical tests to explore observed trends. In order to verify
the SCA for trend analysis, a validation of the MOD10A2 product was done,
consisting of the comparison of snow presence predicted by MODIS with ground
observations. Results indicate that there is an overall agreement of 81 to
98 % between SCA determined from ground observations and MOD10A2, showing
that the MODIS snow product can be taken as a feasible remote sensing tool
for SCA estimation in southern–central Chile. Regarding SCD, no significant
reduction in SCA for the period 2000–2016 was detected, with the exception
of the Aconcagua and Rapel watersheds. In addition to that, an important
decline in SCA in the five watersheds for the period of 2012 and 2016 was
also evident, which is coincidental with the rainfall deficit for the same
years. Findings were compared against ENSO episodes that occurred during
2010–2016, detecting that Niña years are coincident with maximum SCA
during winter in all watersheds. |
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| ISSN: | 1027-5606 1607-7938 |