Detection of Climate Change and Climate Variability Signals in Colombia and the Amazon River Basin through Empirical Mode Decomposition
Alejandra M. Carmona, Germán Poveda
School of Geosciences and Environment, Universidad Nacional de Colombia, Medellin, Colombia

This study aims to identify signs of climate change and climate variability in Colombia and the River Amazon basin using long-term (more than 25 years long) series of rainfall, river discharge and temperature. For filtering pursposes the Empirical Mode Decomposition (EMD) is used, wherby any data series can be decomposed into a finite number of intrinsic mode functions (IMF) under the assumption that at any given time, the data can have many simple oscillatory modes of different frequencies coexisting in the signal and a residual that represents the general trend of the series over time. To determine if the tendency of the EMD residual is statistically significant, the Mann-Kendall test for autocorrelated data is use, and the magnitude of the trend is quantified by the Sen test. Results show that most long-term monthly river discharges series exhibit decreasing trends, whereas the minimum temperature series show increasing trends. Monthly rainfall series in Colombia and the Amazon River basin show a mixed patterns of increasing and decreasing trends.

Keywords: Climate change; Colombia; Water resources; Empirical mode decomposition

Biography: Professor Germán Poveda, PhD. School of Geosciences and Environment, Universidad Nacional de Colombia at Medellin, Colombia. He has been selected as Lead Author of the Chapter on Central and South America for the 5th Assesment Report of the IPCC, due on 2014. He makes part of international scientific steering committees of the “Large Scale Atmosphere-Biosphere Experiment in Amazonia” (LBA) since 2001. and of the “Global Change and Human Health Programme” of the Earth System Science Partnership since 2009. He is member elected of the Colombian Academy of Sciences. He has been selected as a visiting fellow at CIRES (University of Colorado, USA), at the Center for Ecology and Hydrology (Wallingford, UK), and the National Center for Atmospheric Research (NCAR, USA).