ABSTRACT
Until recently, the NAO attracted much less attention than ENSO. However, the NAO has been increasingly linked to the occurrence of flood, drought, storm surge and landslide events in Europe, on a decadal scale at least. In the UK, Woodworth et al. (2007) have shown how extreme sea level events and storm surges exhibit a dependence on the NAO, although the actual magnitude of the sea level change is comparatively
small. Similarly, Macklin and Rumsby (2007), demonstrated a strong relationship between the occurrence of flood events in upland areas of the British Isles with the NAO index over a period of more than 200 years. Elsewhere in Europe, the influence of NAO in flood and drought causation is also evident. For example, Fagherazzi et al. (2005) noted a correlation between a negative NAO index and the occurrence of flooding in Venice. Kaczmarek (2003) observed a strong influence of the NAO on floods in Poland whilst Karabork (2007) demostrated some NAO control on drought occurrence in Turkey. Some evidence is also emerging that the NAO is significant in landslide causation in both Portugal (Zezere et al., 2005) and Italy (Clarke and Rendell, 2006). The NAO may influence hazardous events elsewhere in the northern hemisphere. Xin et al. (2006) found a strong correlation between the NAO and the occurrence of drought in southern China and Cullen et al. (2002) noted a partial dependence of river flooding in the Middle East on the NAO. It seems likely that further relationships will be found as datasets improve in the future.
