The paper analyses, compares and contrasts cross-shore morphodynamic behaviour of four diverse beaches that
have very different regional settings, wave climates and sediment characteristics, with the aid of rarely available
long term measurements of beach profiles and incident waves. The beaches investigated are Narrabeen Beach,
New South Wales, Australia; Milford-on-Sea Beach, Christchurch Bay, UK; Hasaki Coast, Ibaraki Prefecture,
Japan; and Joetsu-Ogata Coast, Niigata Prefecture, Japan. A statistical analysis, equilibrium beach profile analysis
and Empirical Orthogonal Function analysis are used to investigate, compare and contrast spatial and temporal
variability of cross shore beach profiles of the selected beaches at short-, medium- and long-term timescales.
All beaches show evidence of multi-timescale morphodynamic change. Narrabeen Beach profile has the highest
sensitivity to local weather patterns. Milford-on-Sea, Joetsu-Ogata and Hasaki profiles are sensitive to seasonal
variation of the wave climate however, they also show some correlations with regional climate variabilities.
The nature of sediment exchange across the profile, which contributes to profile shape change with time, is
found to be related to sediment characteristics across the profile. At Milford-on-Sea and Joetsu-Ogata, both of
which have composite profiles, sediment exchange between the upper beach and the inter-tidal zone dominates
profile change, irrespective of the distinct differences in sediment composition found in the two beaches. On the
other hand in Narrabeen and Hasaki where beach sediment comprises mediumto find sand, sediment exchange
and hence profile change occur mainly in intertidal and subtidal zones.