| Summary: | The climate variability of the Iberian Peninsula (IP) can be explained in terms of relatively few large-scale atmospheric modes, such as the North Atlantic Oscillation (NAO), the East Atlantic (EA) and the Scandinavian (SCAND) patterns. The present-day IP climatology clearly show that the NAO is the most prominent mode, especially in winter. However, the recent investigations have highlighted that other climate modes play a key role in both modulating the NAO-climate relationship and controlling certain meteorological parameters, although 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 IP, but almost no information is available in the Central 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. The conceptual lake model formulated to understand the present-day influence of the NAO on the limnological evolution of Peñalara (2016 m asl) and Cimera (2140 m asl) alpine lakes (Iberian Central Range, ICR) was established using Pearson's correlation coefficients between seasonal data of the NAO index, climatic data (i.e., precipitation and air temperature data) and ice phenology records from both lakes. The results suggest that the effects of the NAO are only reflected in the thawing process via the air temperature and the insulating effect of snow accumulation on the ice cover. An altitude component is evident in our survey because the effects of the NAO on Peñalara Lake are restricted to winter, whereas for higher Iberian alpine lakes (i.e., Redon Lake, Pyrenees), the effects extend into spring. A latitudinal component is also clear: in northern Europe, the NAO signal is primarily reflected in lake ice phenology via the air temperature, whereas our results confirm that in southern Europe, the strong dependence of both precipitation and temperature on the NAO determines the importance of these ...
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