| Summary: | The climate variability of the Iberian Peninsula (IP) can be explained in terms of relatively few large-scale atmospheric modes of climate variability, such as the North Atlantic Oscillation (NAO), the East Atlantic (EA) and the Scandinavian (SCAND) patterns. Many studies on the present-day IP climatology clearly show that the NAO is the most prominent mode, especially in winter. However, the most recent investigations have highlighted that, in spite of this importance, other climate modes seem to play a key role in both modulating the NAO-climate relationship and controlling certain meteorological parameters, such as the precipitation and/or temperature during a given season of the year. These complex present-day climate dynamics have begun to be well characterized from the meteorological perspective, but little is known about the past evolution of these climate interactions. Furthermore, there is a reasonable understanding of the past NAO evolution in the northern and the southern latitudes of the IP, but almost no information is available on the evolution of this climate mode in the Central IP. This knowledge is crucial to accurately characterizing the past climate evolution of the entire IP. Within this framework, the main aim of this PhD thesis is to characterize the impacts of the NAO on the Central IP over the last 2,000 years. For that, three steps have been followed: 1) the establishment of a conceptual model to depict the NAO influence on the ice phenology of the Peñalara and Cimera alpine lakes (Iberian Central Range, ICR); 2) to characterize the main climate changes in the ICR using Peñalara and Cimera sediments and the spatio-temporal evolution of the NAO, as well as its relationships with other climate modes, over the last two millennia; and 3) to perform a quantitative regional NAO reconstruction using the geochemical composition of the Cimera Lake sediments and a random walk-modularised Bayesian model. The conceptual lake model formulated to understand the present-day influence of the NAO on the ...
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