![]() ![]() The surfaces of both Mars and the moon are mapped to a greater resolution and accuracy than the bottom of the ocean is, Greenaway said in a Reddit post. "The uncertainty of the pressure sensor dominated our overall uncertainty, but instrument manufacturers are making great progress on improving these sensors, so I expect this component of the uncertainty might improve substantially in the future," he said. To make their measurements, Greenaway and his colleagues dropped a pressure sensor on the seafloor to serve as a benchmark for their echo-sounder readings. What's the largest ocean that ever existed on Earth? Is Mount Everest really the tallest mountain on Earth? ![]() "Deploying a pressure sensor to the right place is a bit of a trick too." "After that, we need to correct for the density of the water above the sensor, the gravity pulling that water down, the pressure of the atmosphere, and tides," Greenaway noted. On the floor of the Challenger Deep, the pressure is more than 1,000 times the standard atmospheric pressure at sea level, Guinness World Records noted. With a pressure sensor, building a pressure gauge that is accurate enough at such high pressures is quite challenging, Greenaway said. As a result, the vertical accuracy of an echo-sounder measurement is about 80 feet (25 m), he noted. "As good as they are, the ship systems are really far from the seabed, which limits both the horizontal and vertical accuracy of the measurement."įor instance, with the Challenger Deep, "it takes sound about 14 seconds to go down to the seabed and back," and the salinity, temperature and pressure of the water can affect the speed and path the sound takes, Greenaway said. ![]() Sonar beams from multibeam echo sounders "can produce complete coverage of the seabed," said Greenaway, the marine operations lead on NOAA's new ship construction team. To measure ocean depths using modern instruments, scientists basically have two options: sonar mounted on a ship on the ocean's surface, or a pressure sensor deployed on the seabed that can help gauge how much water lies above it, Greenaway said. Related: What are the deepest spots in Earth's oceans? Its deepest part, Challenger Deep, is highlighted in red. A map of the Mariana Trench in the Pacific Ocean. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |