5-Meter Bathymetric Slope Grid: Portuguese Ledge, Monterey Bay, California, 2008

MBES and side scan data for the South Monterey Bay region were acquired using a 200 KHz/ 400 KHz Reson 7125 sonar aboard the R/V VenTresca by the Seafloor Mapping Lab at California State University Monterey Bay. Prior to data collection, a series of planned survey lines were created using the survey navigation and planning software Hypack 2008 from Hypack, Inc. An Applanix POS/MV 320 v4 system was used to provide position and attitude data during data collection and accounted for vessel motion such as heave, pitch, and roll (position accuracy ± 2m, pitch, roll and heading accuracy ±0.02°, heave accuracy ± 5% or 5cm) with input from a Cnav® enabled NAVCON 2050 GPS. KGPS altitude data were used to account for tide cycle fluctuations and sound velocity profiles were collected with an Applied Microsystems SVPlus sound velocimeter. Data acquisition, post-processing, and final products derived from multibeam bathymetry data were handled by the Seafloor Mapping Lab at CSUMB.

Bathymetry products are presented according to standard California State Mapping Project specifications, including depth-dependent resolutions of 2m for data from the 0-85m depth range, 5m for 80-250m depth range, and 10m for depths of 230-1500m. A comprehensive 5m data set was produced for the total survey coverage only if per block data exceeded 85m depth and 5m resolution products were included.