This data set is a Digital Elevation Model (1 kilometer cell size) covering the offshore area of Northern Alaska and the Northwest, Canada. Over 412,000 depth soundings were acquired from various sources to generate this information. For Alaska, the GEODAS (GEOphysical DAta System) depth soundings acquired from the National Geophysical Data Center (NGDC) were the primary data source. This information was supplemented with depth soundings derived from the NOAA Electronic Nautical Chart for the Beaufort Sea and the United States Minerals Management Service (Outer Continental Shelf Study MMS 2002-017). In addition, depth soundings in feet below mean lower low water (MLLW) were digitized from the July 28, 1990 (1:47943 scale) NOAA #16082 nautical chart for Point Barrow. The Canadian sounding data extending to the Mackenzie Delta were derived from the Digital Ocean product created by Nautical Data International for the Canadian Hydrographic Service (Mackenzie Bay Chart 7662 and Demarcation Bay To Philips Bay Chart 7661.) Soundings from the International Bathymetric Chart of the Arctic Ocean (IBCAO) sheet 3 were incorporated primarily for coverage of the offshore area. The units of these data sets have been standardized in meters.
This data was compiled for the US Mineral Management Service: Mapping and Characterization of Recurring Spring Leads and Landfast ice in the Beaufort and Chukchi Seas (AK-03-06). This data set was specifically designed to analyze the Seaward Landfast Ice Edge (SLIE) and the associated SLIE study area.
There are several ongoing initiatives which may result in improved bathymetry data for Northern Alaska. These include data acquisitions for the Barrow Coastal Observatory, the Arctic Observing Network and Alaska Ocean Observation System.
Any hardcopies or published datasets utilizing these data sets shall clearly indicate their source. If the user has modified the data in any way they are obligated to describe the types of modifications that they have performed. User specifically agrees not to misrepresent these datasets, nor to imply that any changes that they made were approved by the University of Alaska.
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The funding for this effort was provided by the US Mineral Management Service for Mapping and Characterization of Recurring Spring Leads and Landfast ice in the Beaufort and Chukchi Seas (AK-03-06, MMS-71707)
The data sources lacked metadata. However, contacts were made via email to confirm the units used for depth values (feet or meters.) The depth values from various sources were spot checked to confirm consistency between sources.
Each sounding file was visually checked in ArcGIS to confirm placement, projection definition and attribute values (depth). Although there were no depth soundings or elevation readings onshore, an onshore artifact West of Prudhoe Bay was generated by the Inverse Distance Weighted routine. It is anticipated that other artifacts such as spurious offshore peaks may also occur.
While this data set is considered complete for the purposes of this study, there are several ongoing initiatives which may result in improved bathymetry data for Northern Alaska. These include data acquisitions for the Barrow Coastal Observatory, the Arctic Observing Network and Alaska Ocean Observation System.
The source files contained no metadata. The sources were cross checked in ArcMap to confirm that the depth values were sensible. The source data was compiled over the course of 60+ years so it is assumed that varying techniques were employed to obtain depth values and that nearshore sediment changes are a factor in assessing the accuracy. Only a rough estimate of the horizontal accuracy can be made.
The source files contained no metadata. The sources were cross checked in ArcMap to confirm that the depth values were sensible. The source data was compiled over the course of 60+ years so it is assumed that varying techniques were employed to obtain depth values and that nearshore sediment changes are a factor in assessing the accuracy. Only a rough estimate of the vertical accuracy can be made.
Sounding data was extracted from a variety of sources (including ESRI software Electronic Nautical Chart Reader for ArcView 3x and GEODAS software.) Attribute values were calculated to depth in meters and merged into a master file using ArcGIS software. An inverse distance weighted routine was employed in ArcView to create this grid.
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Pixel values represent depth in meters.
For additional information about the structure of ESRI's Grid format visit: www.esri.com
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These data will be made available at the request of the US Mineral Management Service via online tools provided by the Geographic Information Network of Alaska (GINA) at the University of Alaska Fairbanks.
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