Revised depth of the Challenger Deep from submersible transects; including a general method for precise, pressure-derived depths in the ocean

We present a revised estimate of the maximum depth of the Challenger Deep, generally considered the deepest area of the world's oceans, based on a series of submersible dives conducted in June 2020. These depth estimates are derived from acoustic altimeter profiles referenced to in-situ pressure and corrected for observed oceanographic properties of the water-column, atmospheric pressure, gravity and gravity-gradient anomalies, and water-level effects. We also present comprehensive methods to determine depth from observed pressure using modern standards and estimate the associated uncertainty. For the Challenger Deep, the deepest observed seafloor depth was 10,935 m (±6 m at 95% C.I.) below mean sea level. For this work, the error term is dominated by the uncertainty of the pressure sensor used but we show that the gravity correction is substantial. We compare to these new results other recent acoustic and pressure-based measurements for the Challenger Deep.