Publication: Hydrological Drought Assessment over the Argentinean Andes, Links with intra-Seasonal to inter-Decadal Climate Variations
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Year: 2014 ISBN:
Language: Inglés External Link: ...
Type: Abstract
The periods of time when streamflows are below a critical level are extreme adverse conditions that may have significant implications for society, economy and environment. In order to characterize these events at the regional level, we conducted a climatological study of hydrological droughts over the Andean rivers of Argentina. Monthly and daily streamflow data were used from 21 gauging stations distributed between latitudes 30°S and 50°S, from the San Juan River to the Santa Cruz River, with measurement periods ranging from 40 to 110 years. Two methodologies were applied at monthly and daily basis in order to depict the main characteristics of streamflow droughts and deficiencies, respectively. The Standardized runoff index (SRI) was applied to the monthly streamflow time series in order to characterize hydrological droughts during the 1961-2006 period. The SRI quantifies the number of standard deviations that the monthly streamflow on a given time scale deviates from the average value of a location during a particular period. It identifies extreme wet/dry (SRI>=2.0 / SRIal and inter-decadal fluctuations, which differ from Cuyo and Patagonian basins and agrees with the observed patterns based on the SRI. Seasonal deficiencies in the Cuyo basins are linked to climatic variations in the 20-60 days band. These intra-seasonal variations are evident in temperature at different atmospheric levels, with short warm and cold pulses that acts as streamflow regulators during the months of November to February. Links between low-flows and cold temperatures, together with the analysis of atmospheric circulation patterns, can be useful for the development of drought information tools like a medium-range low-flow forecast.
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