Water science news, explainers, and statistics covering freshwater, hydrology, lakes, rivers, groundwater, ice, and Earth’s connected water systems.
Most ocean waves begin when moving air transfers energy to the sea surface. A breeze first roughens otherwise smooth water, then continued wind pressure enlarges those ripples into recognizable crests and troughs. Stronger wind usually supplies energy faster, while a longer blow gives waves more time to grow. The distance over which the wind travels…
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Sonar backscatter measures the strength of sound that returns to a receiver after striking the seafloor or an object in the water. Strong and weak returns form an acoustic image of bottom character. The data can help distinguish exposed rock from soft sediment, trace lava flows and identify wrecks, although echo strength never identifies a…
Multibeam sonar measures the depth and three-dimensional form of the seafloor across a wide swath. Side-scan sonar records detailed acoustic imagery that is especially useful for finding objects and changes in bottom texture. Both transmit sound sideways beneath a survey vessel, but their main products answer different questions. A multibeam map tells a surveyor how…
Bathymetry is the measurement and mapping of water depth. A bathymetric map shows the underwater relief of a lake or ocean basin, including slopes, ridges, canyons, trenches and plains. It is the submerged counterpart of a topographic map, but collecting the measurements is far harder because water hides the landscape from ordinary cameras and most…
