Wind Wave

On 14 July 2000, the LASCO coronagraphs showed a very fast halo coronal mass ejection in association with the radio bursts seen shortly after 10:00 UT. Radio imaging observations by the Nançay radioheliograph (NRH) of these bursts showed a very complex event that can be regarded as global: the sources encompassed all the visible range in longitude and a huge span

In coastal regions sheltered from the direct impact of swell- and storm-wave activity, locally generated wind waves, particularly those associated with strong sea-breeze activity, play a dominant role in controlling nearshore and foreshore processes. Field data collected from the Perth Metropolitan Coast (western Australia) during a typical summer sea-breeze cycle, are presented. It is demonstrated that the nearshore environment responds rapidly to an increase in wind speed (up to 12 m s−1) during the sea breeze, resulting in considerable changes to the nearshore hydrodynamics and morphology. Incident wave energy increased during the sea breeze and was associated with development of a wind-wave field with significant wave heights up to 0.9 m. Nearshore currents responded to this change in wave climate with the development of net offshore near-bed currents and a rapid increase in the mean longshore current from < 0.05 m s−1 to 1.0 m s−1 A 10-fold increase in suspended sediment concentration and a 100-fold increase in the longshore sand transport resulted from the effects of the sea-breeze system. Erosion of the beachface was coincident with the development of the wind-wave field. Sea breeze wave-driven water circulation also completely eroded beach cusps (wavelength 20–30 m), overwhelmed the rip current system associated with the beach cusps and suppressed the infra-gravity wave frequencies in the incident wave and swash record. The beach cusps reformed after the cessation of the sea breeze. It is demonstrated that the beachface is in a constant stage of adjustment to the incident wave energy through the diurnal sea-breeze cycle alternating between dissipative and reflective morphodynamic regimes. The results may be used to determine the impact of a medium-sized storm on the beachface. It is clear that the sea-breeze system plays a major role in controlling the nearshore and foreshore processes not only in this region, but also on other geographic locations where strong sea breezes are present.

There is a growing need to predict ecological responses to long-term habitat change. However, statistical models for marine soft-substratum ecosystems are limited, and consequently there is a need for the development of such models. In order to assess the utility of statistical model- ling approaches for predicting likely changes in species distributions under varying environmental conditions, we tested the utility of logistic modelling and classification approaches. We successfully developed models relating the presence/absence of common intertidal macrofauna to changing envi- ronmental variables such as sediment characteristics, depth/elevation, tidal currents and wind-wave (i.e. wind-generated wave activity) disturbance. The final model for each species contained between 1 and 6 variables, where the percentage correctly predicted was moderate to high, ranging from 59 to 97%. We were also able to identify relationships between higher level variables such as estuary type, basin mor...