Resumo

CERANO PAREDES, Julián et al. Historic variability of reconstructed precipitation with tree-rings for southwestern Coahuila. Rev. mex. de cienc. forestales [online]. 2011, vol.2, n.4, pp.31-45. ISSN 2007-1132.

In Sierra de Arteaga, Coahuila, Mexico, five Douglas-fir chronologies of earlywood, latewood and total ring width were developed from five mountain ranges (La Viga, El Coahuilón, El Tarillal, Los Pilares, and El Morro). To determine a common response for the chronologies a Principal Component Analysis was used. The first Eigenvalue (PC1) explained 72% (p<0.001) of the variance. The El Morro chronology showed the lowest correlation and was discarded from further analysis. A regional chronology was developed with the remaining chronologies, extending for the last 302 years (1700 to 2001). The Response Function Analysis indicated that the earlywood and latewood chronologies responded to the seasonal winter-spring precipitation, explaining 75 and 50% of the variance, respectively, therefore, the earlywood chronology was used as the independent variable for a seasonal precipitation reconstruction. Drought episodes were detected in the reconstruction for the periods 1785-1815, 1853-1882, 1951-1963, and 1970-1985. Pluvials were less common but were present in the periods 1737-1747, 1824-1852, and 1935-1948. In this reconstruction droughts had a return interval of about 50 years, considering that dry periods occurred near by the end and middle of each century (1700, 1750, 1800, 1850, 1900, 1950, and 2000). A Coherence Wavelet Analysis involving the regional earlywood series and Tropical Rainfall Index annual values (TRI) indicated that the El Niño Southern Oscillation (ENSO) has significantly influenced the climate variability of this region, particularly for the periods 1905-1930 and 1974-1988.

Palavras-chave : Coherence Wavelet Analysis; dendrochronology; ENSO; Pseudotsuga menziesii; precipitation reconstruction; drought.

        · resumo em Espanhol     · texto em Espanhol     · Espanhol ( pdf )