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Publication
Impact of atmospheric circulation patterns on coastal dune dynamics, NW Spain
Advisor(s)
Abstract(s)
Dunes in temperate latitudes have experienced a significant stabilization in recent times, essentially as a consequence of the expansion of dense vegetation
cover. Yet, the causes for this gradual stabilization as well as the causes promoting antecedent aeolian mobilization remain poorly understood. The Traba
coastal dune field, located in NW Spain, was examined to explore the causes inducing aeolian activity and subsequent stabilization since 1940. Morphological
changes were identified through the combination of aerial photographs and geophysical techniques. Local wind field regimes were simulated using a regional
climate model to obtain the variability of the most relevant modes of atmospheric circulation in the North Atlantic and European regions; North Atlantic
Oscillation (NAO), Eastern Atlantic (EA) and Scandinavian (SCAND). This allows us to identify the impact of these circulation modes over dune dynamics.
Results document an episode of aeolian activity during the 1950s followed by a gradual stabilization and fixation of the dune coincident with a decrease on
storm and wind intensity. Yet, aeolian sand movement remained active in small areas (blowouts), occurring mainly during the summer. NE winds associated
with a negative phase of the EA explain the movement of sand within the dune field under favorable conditions of sand supply. On the other hand, sand
supply to the dune field from the beach was promoted by NW winds coincident with the summer negative phase of NAO. During winter, the negative NAO
favored frequent SW winds associated with the passage of intense storms, which in turn explain sand remobilization from the beach making sediment
available for the NW winds to blow inland. With this work, it is proven that to understand past and future aeolian activity requires critical consideration of the
variability and impact of the two principal modes of atmospheric circulation in the North Atlantic (NAO and EA). The SCAND mode explaining a lower
percentage of the local wind field variability was also included to achieve higher significance levels of explained variance.
Description
Keywords
Circulação atmosférica Actividade eólica Variações climáticas Duna costeira Dinâmica dunar Espanha (Noroeste)
Citation
González-Villanueva, R... [et al.] - Impact of atmospheric circulation patterns on coastal dune dynamics, NW Spain. In: Geomorphology, Vol. 185 (1 March 2013), p. 96-109