Why it’s So Hard to Measure the Depth of the Ocean
There are a lot of variables The post Why it’s So Hard to Measure the Depth of the Ocean appeared first on Nautilus .
Measuring the depth of the ocean is an incredibly complex task due to the many variables that come into play. Light waves, for instance, travel slower through different media, including water, which itself can vary in characteristics such as temperature, pressure, and dissolved impurities. Sound speed in saltwater is 1,500 meters per second, but it drops to 1,481 meters per second in freshwater. The temperature, pressure, and dissolved impurities in water further complicate the equation.
To measure the depth of the Challenger Deep, located in the Mariana Trench, a team of Japanese oceanographers tested five models using sonar. The study found that the maximum depth of the Challenger Deep's eastern basin ranged from 10,914 to 10,932 meters, a difference of 18 meters. Their preferred model, which incorporated data from 2023 and 1992, estimated the maximum depth to be 10,927 meters (35,850 feet).
However, the study also highlights other challenges in measuring ocean depth. The sonar used has a two-degree-by-two-degree beam configuration, which means even though the beam appears narrow, it actually covers an area of 400 meters (over 1,300 feet) in both directions once it reaches the ocean floor at a distance of nearly 11 kilometers.
Additionally, the speed of the research vessel can distort measurements. Despite these factors, the study successfully narrowed down the depth of the Challenger Deep to a 18-meter range, an impressive feat given the extreme conditions and the fact that humans have never visited the location.
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