Benthic habitat maps, including maps of seabed sediments, have become critical spatial-decision support tools for marine ecological management and conservation. Despite the increasing recognition that environmental variables should be considered at multiple spatial scales, variables used in habitat mapping are often implemented at a single scale. The objective of this study was to evaluate the ...

Abstract. Landfast ice is a common coastal feature in the Arctic Ocean and around Antarctic continent. One contributing stabilizing mechanism grounding of sea ridges shallow water. Recently, scheme representing this effect on dynamics was developed order to improve simulation landfast by continuum-based models. This parameterization assumes that ridged keel thickness proportional mean thickness...

Geoacoustic inversion using a matched-field inversion algorithm is a well-established technique for estimating the geoacoustic parameters of the seabed. This paper demonstrates how parameter estimation can be affected by unknown or wishfully ignored random range dependence of the true environment when the inversion model is--for practicality--assumed to be range independent. Simulations with co...

In standard diffraction theory it is assumed that the water depth is constant and that the seabed is infinitely large. To account for a local varying bathymetry in shallow water (as it can occur for offshore LNG terminals) it is sometimes considered to introduce a second fixed body on the seabed representing this bathymetry in diffraction theory. Based on the results presented in this paper it ...

Affected by the residual of time varying gain, beam patterns, angular responses, and sonar altitude variations, radiometric distortion degrades the quality of side-scan sonar images and seriously affects the application of these images. However, existing methods cannot correct distortion effectively, especially in the presence of seabed sediment variation. This study proposes a new radiometric ...

Testing various models and mechanisms of high frequency seabed scattering was one of primary goals of recent major experiments in sediment acoustics, SAX99 and SAX04, conducted near Ft. Walton Beach, Florida [1-4]. The models to test were based on various assumptions about dominance of certain scattering mechanisms and corresponding theories of scattering. Such models, confirmed by experiments,...

Autonomous underwater vehicles (AUVs) are robotic platforms that are commonly used to map the sea floor, for example for benthic surveys or for naval mine countermeasures (MCM) operations. AUVs create an acoustic image of the survey area, such that objects on the seabed can be identified and, in the case of MCM, mines can be found and disposed of. The common method for creating such seabed maps...

this study compared the use of five different models to describe the growth from birth to 20 weeks of age of kids from both genders of nondescript goats. fifty nine (59) nondescript kids were weighed weekly at the university of maiduguri livestock teaching and research farm, nigeria and the live weights were modeled. biologically relevant variables were estimated for each kid from the logistic,...

We consider the passive direction-of-arrival (DOA) estimation problem using arrays of acoustic vector sensors located in a fluid at or near a reflecting boundary. We formulate a general measurement model applicable to any planar surface, derive an expression for the Cramér–Rao bound (CRB) on the azimuth and elevation of a single source, and obtain a bound on the mean-square angular error (MSAE)...