Shallow and deep landslides induced by rainfall in the Lisbon region (Portugal): assessment of relationships with the North Atlantic Oscillation

• Main Authors: Earth, J. L. Zêzere, R. M. Trigo, I. F. Trigo
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: North Atlantic; North Atlantic oscillation
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.382.4590; http://hal.archives-ouvertes.fr/docs/00/29/91/81/PDF/nhess-5-331-2005.pdf

Abstract. The aim of this study is to assess the impact of the North Atlantic Oscillation (NAO) on both the winter precipitation and the temporal occurrence of different landslide types in Portugal. The analysis is applied to five sample areas located just north of Lisbon, the capital of Portugal. These sites are particularly relevant because actual dates of most of the recent landslide events are known but also because the landslides occurred in a suburban area with growing urbanization pressure. Results show that the large inter-annual variability of winter precipitation observed in western Iberia, i.e. Portugal and parts of Spain, is largely modulated by the NAO mode. In particular, precipitation falling in Portugal between November and March presents a correlation coefficient of R=−0.66 with the NAO index. Precipitation distribution for the reference