Repeat, high-resolution, multibeam, bathymetric surveys of the Monterey Canyon floor were conducted with MBARI’s mapping AUVs (autonomous underwater vehicle). Each AUV carried a Reson 7125 multibeam echosounder (vertical precision of 0.15 meter and horizontal resolution of 1.0 meter). An inertial navigation system combined with a Doppler velocity logger allowed the AUV to fly pre-programmed grids at three knots, while maintaining an altitude of 50 meters above the seafloor, to obtain a nominal line spacing of 130 meters.

See “External Links” below for data access

The axial channel and canyon flanks between 200 and 540 meters water depths were surveyed six times during the CCE. Fourteen out of fifteen turbidity currents captured by the array of CCE instruments passed through this region of the canyon (time of recorded turbidity events). These events caused moorings and instruments to move down canyon at least 30 times. Difference grids obtained by subtracting one survey from the next, show the canyon experienced erosion and deposition of up to +/- 3 meters within a continuous, clearly defined ~200 meter wide swath running along the canyon axis. Sediment gravity flows caused massive remolding of thick sections of the canyon floor in <540 m water depth as a consequence of displacement or fluidization of entire slabs of the seabed during these events. The floor and lower flanks of the canyon from 1350 to 1880 m water depths were also mapped with AUVs six times during the CCE (datasets on IEDA). Between these repeated surveys, three sediment gravity flow events extended beyond 1850 meters water depth. Unlike in the upper canyon where events caused wholesale reorganization of geomorphological features, changes to the lower canyon morphology involved a more moderate re-sculpting of the features. Navigation issues The AUV has no access to GPS fixes when it is below the sea surface so it depends on a Doppler velocity logger and an inertial navigation system to dead reckon. The AUV position can drift during its descent and while mapping. In principle, by repeating surveys we can detect change by differencing grids. However, the precision of the dead-reckoning navigation is inadequate given the resolution of the grids. In order to make accurate difference grids, successive surveys must be spatially co-registered using features that are identical, and unmoving.  A significant effort was made to co-register surveys together at each site using MBnavadjust, part of MBSystem. The surveys in the CCE Shallow site are all co-registered together, but some of the surveys in the CCE Deep site couldn’t be co-registered without creating navigation artifacts. However, pairs of surveys that straddled the two largest turbidity events were co-registered. Grid pairs at the CCE Deep site include, start (Topo1m_CCEDeep_20151105m1_UTM.grd) and end (Topo1m_CCEDeep_20170323m1_UTM.grd) of experiment, before (Topo1m_CCEDeep_20151202m1_UTM.grd) and after January 15, 2016 (Topo1m_CCEDeep_20160322m2_UTM.grd) and before (Topo1m_CCEDeep_20160418m4_UTM.grd) and after September 1, 2016 (Topo1m_CCEDeep_20161206m2_UTM.grd). Data are projected in UTM zone 10N.

Surveys:

 

Survey Site Grid
20151104m1 CCE Shallow Topo1m_CCEShallow_20151104m1_UTM.grd
20151201m1 CCE Shallow Topo1m_CCEShallow_20151201m1_UTM.grd
20160128m1 CCE Shallow (part 1) Topo1m_CCEShallow_20160128m1_UTM.grd
20160129m1 CCE Shallow (part 2)
20160321m1 CCE Shallow (part 1) Topo1m_CCEShallow_20160321m1_UTM.grd
20160321m2 CCE Shallow (part 2)
20161207m2 CCEShallow Topo1m_CCEShallow_20161207m2_UTM.grd
20170221m3 CCEShallow Topo1m_CCEShallow_20170221m3_UTM.grd
20170222m2 CCEShallow Topo1m_CCEShallow_20170222m2_UTM.grd
20151105m1 CCE Deep (part 1) Topo1m_CCEDeep_20151105m1_UTM.grd
20151106m1 CCE Deep (part 2)
20151202m1 CCE Deep Topo1m_CCEDeep_20151202m1.grd
20160322m2 CCE Deep Topo1m_CCEDeep_20160322m2.grd
20160418m4 CCE Deep Topo1m_CCEDeep_20160418m4.grd
20161206m2 CCEDeep Topo1m_CCEDeep_20161206m2.grd
20170323m1 CCEDeep (part 1) Topo1m_CCEDeep_20170323m1.grd
20170323m2 CCEDeep (part 2)

Datasets hosted by MGDS have their own DOI and can be cited individually.

Please cite this online data report as follows:

Lundsten, E. (2019). Coordinated Canyon Experiment (CCE) data report. MBARI.org. Retrieved 11/4/2022. from

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