Abstract:
This work investigates historical variation and trends in storm climate for the South Portugal region, using data from wave buoy measurements and from modelling, for
the period 1952 to 2009. Several storm parameters (annual number of storms; annual number of days with storms; annual
maximum and mean individual storm duration and annual 99.8th percentile of significant wave height) were used to analyse: (1) historical storminess trends; (2) storm parameter variability and relationships; and (3) historical storminess and its relationship to the North Atlantic Oscillation (NAO). No statistically significant linear increase or decrease
was found in any of the storm parameters over the period of interest. The main pattern of storm characteristics and extreme
wave heights is an oscillatory variability with intensity peaks every 7–8 yr, and the magnitude of recent variations is comparable with that of variations observed in the earlier parts of the record. In addition, the results reveal that the NAO index is able to explain only a small percentage of the variation in storm wave height, suggesting that more local factors may be of importance in controlling storminess in this
region.