Reconstrucción de la variabilidad climática para el oeste de Chihuahua, México, empleando un enfoque dendrocronológico
Tree rings play a relevant role for the reconstruction of climatic variables on centuries or millennia-scale. In the presence of anthropogenic climate change, and in the absence of extensive meteorological records, dendrochronological studies in forested areas have gained more importance in recent d...
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| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2021 |
| País: | España |
| Institución: | Universitat Politècnica de Catalunya (UPC) |
| Repositorio: | UPCommons. Portal del coneixement obert de la UPC |
| Idioma: | español |
| OAI Identifier: | oai:upcommons.upc.edu:2117/361631 |
| Acceso en línea: | https://hdl.handle.net/2117/361631 https://dx.doi.org/10.5821/dissertation-2117-361631 |
| Access Level: | acceso abierto |
| Palabra clave: | Dendrocronología Precipitación Sequías Variabilidad climática Dendrochronology Precipitation Droughts Climatic variability El Niño-Oscilación del Sur (ENOS) El Niño–Southern Oscillation (ENSO) Àrees temàtiques de la UPC::Desenvolupament humà i sostenible |
| Sumario: | Tree rings play a relevant role for the reconstruction of climatic variables on centuries or millennia-scale. In the presence of anthropogenic climate change, and in the absence of extensive meteorological records, dendrochronological studies in forested areas have gained more importance in recent decades because of the high-resolution data that can be obtained from tree-rings. These data may allow to analyze trends in the series and the influence of climatic phenomena on their variability in order to predict extreme climate events and to know their possible impacts on both ecosystem dynamics and the social community. In this research project, two case studies were analyzed with the common objective of reconstructing the climatic variability for western Chihuahua, Mexico. In the first case study, tree-ring chronologies for Pseudotsuga menziesii (Mirb.) Franco and Pinus arizonica Engelm.were developed with the objective of both evaluating the influence of climatic variables on the total growth of both species and examining possible shifts in climate regime through instrumental data. In order to evaluate the relationships between climate data and the standardized tree-ring width data of both species, static correlation and response functions were computed based on partial regression coefficients from 1000 bootstrapped estimates. Further, a moving correlation analysis was calculated using a 40-year window with 1-year offset and an 18-month window of meteorological records. It was detected that the precipitation from November to May positively influenced the growth of both species even though it only represented the 20% of the annual rainfall while the winter-spring maximum temperature negatively affected their development. Besides climatic response of P. menziesii has not varied over time while P. arizonica has begun to respond similarly to P. menziesii in recent years. In a climate change scenario derived from human activity, with less rain and higher temperatures, it is expected that both species are affected in their growth response and are susceptible to insect outbreaks or fires events. In the second case study, two chronologies were developed in order to reconstruct the variability of precipitation: El Santuario based on the growth rings of P. menziesii, P. arizonica and Pinus strobiformis Engelm., and La Norteña with P. arizonica. It was determined a significant correlation between the two series and a regional chronology was developed. Through an analysis of the response function, it was determined that the October-June precipitation was the one that most influenced tree growth, accounting for 52% of the variability. The winter-spring precipitation was reconstructed for the last 359 years (1660-2018). The reconstructed chronology was verified with instrumental climatic data, a spatial correlation analysis with drought indices and historic archives. Severe droughts were detected for the periods 1680-1688, 1695-1707, 1817-1822, 1889-1897, 1908-1911, 1925-1930, 1934-1939 and 2011-2018. The extreme droughts for the periods 1751-1768, 1807-1810 and 1945-1956 stood out as those in which much of the Mexican territory was affected, causing a great economic damage to millions of people. The wavelet coherence analysis indicated that El Niño-Southern Oscillation (ENSO) phenomenon has significantly modulated the variability of the reconstructed precipitation at different time and frequency scales over the last 100 years. |
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