Hydroclimatological variations in subtropical regions of Northwestern Argentina during the last centuries.

FERRERO, M.E.; VILLALBA, R.; PRIETO, M.R.

Melbourne

Conferencia; 9th International Conference on Dendrochronology; 2014

University of Melbourne

The use of streamflows for irrigation of agricultural fields is a common practice in subtropical dry regions of NW Argentina (22°-29°S; 61°-68°W). For more than four centuries, tropical rivers in northwestern Argentina have been used for consumption and navigation of small boats. These activities are seriously affected by climate variability. Analyses of instrumental precipitation and streamflow records for the past 60 years indicate a period of enhanced inter-annual and inter-decadal variations during the last three decades (since 1970s). In this contribution, we analyze tree-ring based reconstructions of precipitation and streamflow variations for major South American subtropical basins and comparethese reconstructions with historical archives recorded by the Spaniards since the 16th century. Catastrophic events such as droughts and floods were particularly important due to the direct effects on human activities related to natural resources, famine and diseases. The development of climate-sensitivity tree-ring records in complement with historical information, provide consistent patterns on past hydroclimatic variations for subtropical montane and lowland regions in the subtropics. These long-term reconstructions not only allow the identification of cycles in water supply but also the assessment of human vulnerability in relation to large interannual and longer climatic variations in subtropical South America.