Reconstruction of long-term winter streamflow in the Gulf of California continental watershed

Applying multiple regression techniques to tree-ring series from Sierra de la Laguna in Baja California Sur, Mexico and Sierra Madre Occidental in Durango, and Tlaxcala, Mexico (A.D. 1384-1997), reconstruction of winter streamflow was performed for data from the central and southern regions of the Gulf of California continental watershed. Each region was defined after applying Varimax Rotated Empirical Orthogonal Function analysis. Streamflow reconstruction was possible from 1840 to 1992 for the central region and from 1712 to 1993 for the southern region. The power spectrums of the reconstructed streamflow series and the Index of the Pacific Decadal Oscillation series (IPDO) show evidence of low frequency (decadal-scale) variations around 40 and 80 years. Tendencies in reconstructed streamflow series and in the IPDO are analyzed and discussed. We conclude that streamflow reconstruction was attainable on a decadal temporal scale. In this sense, the IPDO may be considered a good indicator of future tendencies (in decades) in winter streamflow in the study zone.