## 4 Results
### Wave Climate and Volumetric Changes  
The dimensionless fall velocity values showed little variability among the beaches and remained close to one (reflective state) for each beach and for the whole surveyed period. Figure 5: The evolution of the morphology along the beach profiles, as follows: (**a**) Mari Ermi; (**b**) Is Arutas; and (**c**) Maimoi. Where DGPS data were not accurate, the profiles were not represented. X, Y and Z axes represent the date of survey, the cross-shore distance and the elevation recorded during the beach profile acquisition. The elevation data for each survey are side-by-side and no interpolation was performed among them. The values of \(\Omega\) calculated for each beach are shown in Figure 6. Also, the values of the averaged Iribarren number (\(\xi_{0}\)), calculated along each beach profile, were about one for the overall profiles (Table 1). These values show that the breaking waves type on the studied beach can be considered as the plunging type (0.5 \(<\)\(\xi_{0}\)\(<\) 3.3). The significant wave heights and the peak wave periods are shown in Figure 6. Higher significant wave heights occurred from October 2010 to late January 2011, these events accounted for peak periods higher than 9 s. The highest wave height was recorded on 16 November 2010 (6.65 m), and the highest peak period was recorded on 26 December 2010 (12.1 s). During the whole surveyed period, the majority of the recorded events came from NW (Mistral); however, W-NW events were also recorded during the winter, and only two events came from S (Figure 6). The storm power index (Ps) of the single storms, the cumulative value of the Ps, the number of storms occurred among each topographic survey, together with the volumetric changes (m\({}^{3}\) m\({}^{-1}\)) along each transect, are reported in Figure 7.  
The single storm accounting for the highest value of Ps occurred in October (Hs max ~5 m Tp ~11 s and D ~80 h from 17 October to 20 October, Figures 6 and 7). Nine storms occurred from 23 September 2010 to 5 November 2010. From 5 November to 14 December eleven storms occurred. From 14 December to 17 January 2011 seven storms occurred, and from 17 January 2011 to 4 March 2011 a total of thirteen storms occurred. After the 4 March very few storms were recorded (Figure 7). The storms frequency and their intensity were described also by the cumulative Ps. The slope of this curve is steeper in the following two periods: the first from late October to mid-January, and the second between early February and early March. This is due to the highest energetic storms occurring during these periods. Figure 6: (**a**) The significant wave height and \(\Omega\) value (mean values for the period between the topographic survey) on the following beaches: Is Arutas (red dot), Mari Ermi (blue circle) and Maimoi (black cross). (**b**) The wave peak period. Major changes occurred on the Is Arutas and Maimoi beaches. On Mari Ermi beach the cumulative volume changes were lower in comparison to the other two studied beaches. The main changes along the beach profiles occurred from early November to early March, which is the period with the highest wave height. During the surveyed period, beach profile changes on Mari Ermi beach did not exceed 25 m\({}^{3}\) m\({}^{-1}\). The highest volumetric changes were observed from late January to early March, mainly on the northern and southern profiles (Figure 7a). These profiles changed in opposite ways to each other. At the end of the monitored period, the total volumetric changes in respect to the first topographic survey was very low and close to 0 m\({}^{3}\) m\({}^{-1}\) (Figure 7a). On Is Arutas beach the maximum volumetric changes accounted for a value of about 41 m\({}^{3}\) m\({}^{-1}\) on the northern profile, simultaneously the southern profile showed an opposite volumetric change  
Figure 7: The cumulative volumetric changes (m\({}^{3}\) m\({}^{-1}\)) on the following beach profiles: Mari Ermi (**a**); Is Arutas (**b**); and Maimoi (**c**).