Dendrochronological records as a basis for historical reconstruction levels Paraguai river, the main tributary of the Rio de la Plata Basin

LIDIO LOPEZ; RICARDO VILLALBA

San Rafael

Workshop; Documenting, understanding and projecting changes in the hydrological cycle in the American Cordillera; 2014

Inter-American Institute for Global Change Research (IAI)

Studying the climate and its spatio-temporal variation requires knowledge of long-term time series. Making an analysis of climate variability based on instrumental hydrometeorological series in tropical regions is very limited because these records are very few and are not available exceeding 100 years. The historical determination of abnormal flows mainly in the upper and middle part of the basins will allow the identification of favorable and deficit periods. Dendrochronology is one of the most appropriate techniques to extend the series of climatic variables, allowing reconstruction of climate events from tree growth techniques. Growth rings are a high resolution proxy-climate indicator, providing continuous series, precisely dated to year of formation with annual resolution. Employing the chronology network built for the Cerrado region from growth rings of Centrolobium microchaete (tarara amarilla), the series of seasonal flows was rebuilt from 1798 for one of the major rivers that make up the Plata basin, the Paraguai. The regional chronology of C.microchaete is strongly related (r = 0.59) with the mean annual discharge taken at the naval base Ladário, South Matogrosso. This correlation was higher (r = 0.62), if the minimum discharge is considered, thus being a great predictor of the environmental conditions of the vast Cerrado region.