Swath Bathymetry Surveys of the Monterey Bay Area from Point Año Nuevo to Moss Landing, San Mateo, Santa Cruz, and Monterey Counties, California

Figures

Figure 1

Map of the survey area between Point Año Nuevo and Moss Landing, California. Survey planning blocks are shown with RTK base stations and repeater.

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Figure 2

Data Processing workflow showing data acquisition and processing hardware and software along with process steps.

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Figure 3

VDatum software dialog window showing settings used to transform vertical coordinates from NAD83(CORS96) to NAVD88.

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Figure 4

Hillshaded bathymetry image of the Monterey Bay, California, project area.

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Figure 5

Gain-normalized backscatter amplitude image for the Monterey Bay, California, project area.

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Figure 6

Plot of depth-normalized 2 sigma standard deviation for the Monterey Bay, California, project area.

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Figure 7

Plot of depth-normalized 2-sigma standard deviation values in an area with rocky nearshore topography. The high roughness leads to higher standard deviation values because elevation varies within the 2-m grid cells.

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Figure 8

Plot of depth-normalized 2-sigma standard deviation values at the outer survey boundary between blocks G and H (figure 1). Values are lower because of deeper water, but note how the higher values fall along rock ledges at the canyon edge. Higher values west of the canyon are due to track spacing that is approaching the limits of the sonar.

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Figure 9

Plot of depth-normalized 2-sigma standard deviation values near Moss Landing. Higher values along the steep slopes of the canyon wall are due to elevation differences within a 2-m grid cell. Higher values near shore are in shallow water.

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Figure 10

Depth-normalized 2-sigma standard deviation values across several survey lines relative to tie line. Note the "ridges" as you approach nadir. These appear to be artifacts of the SWATH mapping sonar.

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Figure 11

Plot of depth-normalized 2 sigma standard deviation values for all tie-line profiles. Higher standard deviation values approaching shore are due primarily to high relief in the nearshore rocky areas (see figure 7).

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Figure 12

Plot comparing Monterey Bay, California, project data with IHO Survey Standards. Total vertical uncertainty generally was within the limits specified by IHO Order 1 or Special Order surveys. Exceptions generally follow the same pattern as for standard deviations.

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Figure 13

Plot comparing survey data near Point Año Nuevo, California, with IHO Survey Standards. Note that the areas where total vertical uncertainty exceeds IHO Order 1 specifications primarily are over areas with surface relief that exceeds the grid-cell resolution.

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Figure 14

Plot comparing survey data near the head of Monterey Canyon with IHO Survey Standards. Note that most of the areas where total vertical uncertainty exceeds IHO Order 1 specifications are on the steeply sloping canyon walls. A few lines near shore exceeding IHO standards may not have been trimmed properly to minimize noise at the outer edge of the beam.

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For more information, contact David Finlayson.