Multi-centuries mean summer temperature variations in the Southern Rhaetian Alps reconstructed from Larix decidua blue-intensity data
Abstract. Ongoing climate change is likely to cause a worldwide temperature increase of 1.5 °C by the mid-century. To contextualize these changes in a long-term context, historical climatological data extending beyond data obtained from instrumental records are needed. This is even more relevant in remote areas characterized by complex climatic influences and where climate sensitivity is pronounced, such as the European Alps. Dendroclimatology has been recognized as a fundamental tool for reconstructing past climate variations because its temporal resolution is higher than that of other proxies. In this study, we present a comprehensive dendroclimatic analysis in which blue intensity (BI) data derived from European larch (Larix decidua Mill.) trees in the Southern Rhaetian Alps were employed. By establishing the relationships between BI patterns in tree rings and climate variables, the possibility of using the obtained data for constructing a high-resolution, long-term climate record is explored. The results showed that BI data from European larch share greater variance with June–August mean temperatures than total ring width measurements. Moreover, the BI performance as a temperature predictor resulted temporal and spatial quite-stationarity and its regression indices are comparable to those obtainable by data from the more expensive wood density method. The results from this analysis will extend the current knowledge on the applicability of using BI data to study European larch, and the reconstruction described herein is the first attempt to determine whether this proxy can be utilized for dendroclimatic aims. Thus BI data represent a new tool for extending our knowledge beyond that obtained from instrumental records and facilitating a more robust evaluation of climate models and future climate scenarios.
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