ABSTRACT. The relationship between instability indices and extreme daily rainfall over state of Rio Grande do Sul, Brazil, is studied, as well as the main differences between extreme and ordinary rainfall events. A total of 105 extreme and 342 ordinary rainfall events w...

The performance of a sonar system operating in shallow water is closely linked to the properties of the seabed. At the same time the sensitivity of the acoustic signal (or background) to sediment properties gives an acoustic sensor the potential to measure precisely tho...

The application of acoustic methods for the classification of bottomhabitats is based mostly on the analysis of measured parameters without relating them to the bathymetric structure. Geological complexity and biological patterns are closely related to bathymetry. This ...

This study presents a novel method to identify optically deep water using purely spectral approaches. Optically deep waters, where the seabed is too deep for a bottom reflectance signal to be returned, is uninformative for seabed mapping. Furthermore, owing to the atten...

The continuous dredging of shipping channels is a commom problem in most estuaries. Shoals constitute navigational hazards, which have to be removed to guarantee a safe access to the adjacent harbors. Dredging is always associated with the dumping of dredge spoil at dec...

Acoustic seabed classification with single-beam sounders involves discriminating among bottom types using attributes of their echoes. One attribute that is rich in sediment information is the duration of these echoes, but it needs to be interpreted with care because it ...

The recent development techniques of acoustic sound survey can provide clearly the inferences of seabed texture, grain size or habitat, seafloor bathymetry and sunken archaeology. Acoustic seabed classification and mapping are possible by using a wide range of acoustic ...

Abstract Acoustic seabed classification is a useful tool for monitoring marine benthic habitats over broad-scales (>1 km 2 ) and meso-scales (10 m 2 –1 km 2 ). Its utility in this context was evaluated using two approaches: by describing natural changes in the temporal ...

Single-beam acoustic seabed classification continues to be a popular method for mapping seabeds and their sediments. Modern methods can generate maps of acoustic classes that are useful and reasonably accurate. Research toward improved methods continues. A continuing im...

Dividing sonar images into regions that have similar seabeds is often done by expert interpretation. Automated classification systems are becoming more widely used. This paper describes techniques, based on image amplitudes and texture, that lead to useful and practical...