sounding

Sounding is the act of measuring depth or vertical extent in a given environment. The term is used in nautical, hydrographic, meteorological, and medical contexts, and it can refer to different techniques and tools depending on the field.

In maritime and hydrographic use, sounding historically involved a weighted line, or sounding line, lowered from a vessel to determine water depth. The line often carried marks to record depth, and the weight sometimes had tallow to sample the seabed for bottom type. Modern practice commonly uses echo sounding and multibeam sonar, which emit sound waves and interpret their reflections to produce depth measurements and bathymetric maps. Soundings are essential for charting safe navigation routes, locating seafloor features, and supporting offshore engineering projects.

In meteorology, atmospheric sounding refers to obtaining vertical profiles of weather parameters such as temperature, humidity, and pressure. This is typically achieved using radiosondes carried aloft by weather balloons or through specialized instruments on aircraft and satellites. Raw soundings contribute to weather forecasting and the study of atmospheric stability and convection.

Medical and sexual contexts also use the term sounding. Urethral sounding involves inserting slender probes, called sounds, into the urethra for diagnostic purposes or, in some contexts, as a sexual practice. It carries risks such as infection or trauma if performed improperly; it is generally advised to seek guidance from medical professionals and to use sterile equipment and appropriate lubrication when performed in a clinical setting or under supervision.

Overall, sounding denotes a method of assessing depth or internal structure across disciplines, with each domain applying its own equipment and procedures.