Editing Challenger Deep (section)

===2016 – RV ''Sonne''===
[[File:RV Sonne 2014 1.jpg|thumb|German maritime [[research vessel]] ''Sonne'']]
In November 2016 sonar mapping of the Challenger Deep area was conducted by the [[Royal Netherlands Institute for Sea Research]] (NIOZ)/[[GEOMAR Helmholtz Centre for Ocean Research Kiel]] aboard the 8,554-ton Deep Ocean Research Vessel [[RV Sonne (2014)|''Sonne'']]. The results were reported in 2017. Using a Kongsberg Maritime EM 122 multi-beam echosounder system coupled to positioning equipment that can determine latitude and longitude the team determined that the Challenger Deep has a maximum depth of {{convert|10925|m|ft|abbr=on}} at {{Coord|11|19.945|N|142|12.123|E}} ({{Coord|11.332417|N|142.20205|E|scale:100000}}), with an estimated vertical uncertainty of ±{{convert|12|m|ft|0|abbr=on}} at one standard deviation (≈ 68.3%) confidence level. The analysis of the sonar survey offered a {{convert|100|by(x)|100|m|ft|0}} grid resolution at bottom depth, so small dips in the bottom that are less than that size would be difficult to detect from the 0.5 by 1 degree sonar-emissions at the sea surface. Each 0.5-degree beam width sonar ping expands to cover a circular area about {{convert|96|m|ft}} in diameter at {{convert|11000|m|ft|0}} depth.<ref>{{cite web| url = https://epic.awi.de/id/eprint/45364/1/Kongsberg_302440ae_em122_product_description.pdf| title = Product description Kongsberg Maritime EM 122 Multibeam Echo Sounder| access-date = 11 November 2019| archive-date = 11 November 2019| archive-url = https://web.archive.org/web/20191111093211/https://epic.awi.de/id/eprint/45364/1/Kongsberg_302440ae_em122_product_description.pdf| url-status = live}}</ref> The horizontal position of the grid point has an uncertainty of ±{{convert|50|to|100|m|ft|0|abbr=on}}, depending on along-track or across-track direction. This depth ({{convert|59|m|ft|0|abbr=on}}) and position (about {{convert|410|m|ft|0|abbr=on}} to the northeast) measurements differ significantly from the deepest point determined by the Gardner et al. (2014) study.<ref name="Ocean mixing in deep-sea trenches">{{cite web|url=http://tmp.hansvanharen.nl/pedef/2017DSRi.pdf |archive-url=https://web.archive.org/web/20190119174404/http://tmp.hansvanharen.nl/pedef/2017DSRi.pdf |archive-date=2019-01-19 |url-status=live|title=Ocean mixing in deep-sea trenches: New insights from the Challenger Deep, Mariana Trench. Deep-Sea Research, Part I. Oceanographic Research Papers, 129, 1–9|last1=van Haren |first1=H. |last2=Berndt |first2=C. |last3=Klaucke |first3=I. |date=2017|website=www.vliz.be}}</ref><ref name="RV SONNE 252 Cruise Report">{{cite web|url=https://www.portal-forschungsschiffe.de/lw_resource/datapool/_items/item_335/03g0252a_20170216_fahrtbericht.pdf |archive-url=https://web.archive.org/web/20181215173459/https://www.portal-forschungsschiffe.de/lw_resource/datapool/_items/item_335/03g0252a_20170216_fahrtbericht.pdf |archive-date=2018-12-15 |url-status=live|title=RV SONNE 252 Cruise Report / Fahrtbericht Yokohama: 05.11.2016 Nouméa: 18.12.2016 |author=Christian Berndt GEOMAR Helmholtz Centre for Ocean Research Kiel|date=2016|website=www.portal-forschungsschiffe.de}}</ref><ref name="RV SONNE 252 Cruise Report Raw Multibeam Data">{{cite book|title=Raw multibeam EM122 data: transits of SONNE cruise SO252 (Pacific). PANGAEA|last1=Berndt |first1=Christian |last2=Klaucke |first2=Ingo |last3=Wölfl |first3=Anne-Cathrin |date=2018|website=www.pangaea.de|doi=10.1594/PANGAEA.896077|type=Data Set|publisher=PANGAEA – Data Publisher for Earth & Environmental Science|chapter=Bathymetry}}</ref> The observed depth discrepancy with the 2010 sonar mapping and Gardner et al 2014 study are related to the application of differing sound velocity profiles, which are essential for accurate depth determination. ''Sonne'' used CTD casts about 1.6&nbsp;km west of the deepest sounding to near the bottom of the Challenger Deep that were used for [[Sound speed profile|sound velocity profile]] calibration and optimization. Likewise, the impact of using different projections, datum and ellipsoids during data acquisition can cause positional discrepancies between surveys.<ref name="Stewart, Heather & Jamieson, Alan. (2019)">{{cite journal |url=http://nora.nerc.ac.uk/id/eprint/524544/1/Stewart_and_Jamieson_2019_The%20five%20deeps.pdf |last1=Stewart |first1=Heather |last2=Jamieson |first2=Alan |year=2019 |title=The five deeps: The location and depth of the deepest place in each of the world's oceans |journal=Earth-Science Reviews |volume=197 |issue=197 |page=102896 |doi=10.1016/j.earscirev.2019.102896 |bibcode=2019ESRv..19702896S |s2cid=199113259 |access-date=15 October 2019 |archive-date=14 March 2020 |archive-url=https://web.archive.org/web/20200314064707/http://nora.nerc.ac.uk/id/eprint/524544/1/Stewart_and_Jamieson_2019_The%20five%20deeps.pdf |url-status=live }}</ref>