| Term |
Description |
| Accretion |
The process of sediment accumulating on the sea bed leading to a raising of bed levels |
| Acoustic provinces |
Areas of seabed with similar reflective properties for sound waves. |
| Advection |
The mixing of different water bodies by horizontal motion; mass transfer of matter |
| Aggradation |
Progressive increase in sedimentation (see also accretion). |
| Aggregates |
Sand, gravel and crushed rock suitable for use in the construction industry for mixing with a matrix to form concrete, macadam, mortar or plaster, or used alone as in railway ballast, unbound road-stone or graded fill. |
| Amphidromes |
Locations where tidal range is zero. |
| Amplitude |
Half of the peak-to-trough range (or height) of a waveform. |
| Antecedent |
Conditions defined by what went before (e.g. preceding geological epoch) |
| Anthropogenic |
Produced or caused by humans. |
| Armour stone |
Large quarried stone or specially shaped concrete block used as primary protection against wave action. |
| Armouring |
Protection of erodible materials by resistant materials. |
| Average Hsig |
Average significant wave height recorded during a storm event (see significant wave height). |
