International Bathymetric Chart Of The Arctic Ocean Research Articles

The International Bathymetric Chart of the Arctic Ocean Version 4.0

Bathymetry (seafloor depth), is a critical parameter providing the geospatial context for a multitude of marine scientific studies. Since 1997, the International Bathymetric Chart of the Arctic Ocean (IBCAO) has been the authoritative source of bathymetry for the Arctic Ocean. IBCAO has merged its efforts with the Nippon Foundation-GEBCO-Seabed 2030 Project, with the goal of mapping all of the oceans by 2030. Here we present the latest version (IBCAO Ver. 4.0), with more than twice the resolution (200 × 200 m versus 500 × 500 m) and with individual depth soundings constraining three times more area of the Arctic Ocean (∼19.8% versus 6.7%), than the previous IBCAO Ver. 3.0 released in 2012. Modern multibeam bathymetry comprises ∼14.3% in Ver. 4.0 compared to ∼5.4% in Ver. 3.0. Thus, the new IBCAO Ver. 4.0 has substantially more seafloor morphological information that offers new insights into a range of submarine features and processes; for example, the improved portrayal of Greenland fjords better serves predictive modelling of the fate of the Greenland Ice Sheet.

Three-dimensional desktop morphometric models for the Arctic Ocean floor

Abstract. We present results of the first phase of an ongoing project to create a system for three-dimensional (3D) geomorphometric modeling of the Arctic Ocean submarine topography. In this phase, we developed a testing, lowresolution desktop version of the system. We utilized a small, 5-km gridded digital elevation model (DEM) extracted from the International Bathymetric Chart of the Arctic Ocean (IBCAO) version 3.0. From the smoothed DEM, we derived digital models of several morphometric variables: horizontal, vertical, minimal, and maximal curvatures, catchment and dispersive areas, as well as topographic and stream power indices. To construct and visualize 3D morphometric models, we applied an original approach for 3D terrain modeling in the environment of the Blender package, free and open-source software. Finally, we present a series of 3D morphometric models with perspective views from the Atlantic, Eurasia, the Pacific, and North America. The experiment showed that the approach is efficient and can be used for creating next, desktop and web versions of the system for visualizing 3D morphometric models of higher resolutions.

Mapping submarine glacial landforms using acoustic methods

The mapping of submarine glacial landforms is largely dependent on marine geophysical survey methods capable of imaging the seafloor and sub-bottom through the water column. Full global coverage of seafloor mapping, equivalent to that which exists for the Earth's land surface, has, to date, only been achieved by deriving bathymetry from radar altimeters on satellites such as GeoSat and ERS-1 (Smith & Sandwell 1997). The horizontal resolution is limited by the footprint of the satellite sensors and the need to average out local wave and wind effects, resulting in a cell size of about 15 km (Sandwell et al. 2001). A further problem in high latitudes is that the altimeter data are extensively contaminated by the presence of sea ice, which degrades the derived bathymetry (McAdoo & Laxon 1997). Consequently, the satellite altimeter method alone is not suitable for mapping submarine glacial landforms, given that their morphological characterization usually requires a much finer level of detail. Acoustic mapping methods based on marine echo-sounding principles are currently the most widely used techniques for mapping submarine glacial landforms because they are capable of mapping at a much higher resolution. Although the accuracy and resolution of echo-sounding methods are continually being improved, the portion of the world's ocean floor that has been acoustically surveyed is increasing only slowly. This lack of coverage is particularly true for those areas of the oceans covered by sea ice and infested with icebergs, where glacial landforms are an abundant component of continental shelf and fjord morphology. This is illustrated by the fact that only about 11% of the Arctic Ocean had been mapped using modern multibeam sonar technology by 2012 when the latest International Bathymetric Chart of the Arctic Ocean (IBCAO) was compiled (Jakobsson et al. 2012). A similar estimate of the mapped portion of the seafloor …

The physiography of High Arctic cross-shelf troughs

A comprehensive inventory of High Arctic cross-shelf troughs is compiled from International Bathymetric Chart of the Arctic Ocean (IBCAO) bathymetric data (v. 3.0). The location of 75 cross-shelf troughs is presented alongside a synthesis of their key physiographic characteristics and available glacial-geological evidence. The troughs are interpreted to have been occupied intermittently and eroded by marine-terminating ice streams that traversed the shelf during at least one, and often many Quaternary full-glacial periods. Considerable variation in cross-shelf trough physiography exists in the High Arctic; trough lengths range between 35 and 1400 km, widths from 12 to 260 km, and maximum depths from 200 to 1000 m. The longest cross-shelf troughs extend through inter-island channels on the Beaufort Sea, Queen Elizabeth Islands and Barents–Kara Sea margins. The gradient of the upper-slope beyond High Arctic glacial troughs, which ranges between 0.3° and 13°, is shown to have a negative relationship with palaeo-ice stream drainage basin area and trough length. Glacial-sedimentary depocentres or trough-mouth fans (TMFs) are inferred on the basis of bathymetric and, where available, seismic evidence, to exist beyond the majority of High Arctic cross-shelf troughs. Evidence of shelf progradation or TMF development is absent from the slope beyond several High Arctic troughs, probably as a result of limited sediment supply to the margin and/or sediment by-passing of the upper-slope. On the South Greenland continental margin, it is likely that steep slopes prevented the development of significant glacial-sedimentary depocentres beyond cross-shelf troughs or that glacigenic debris has been removed from the upper-slope by submarine slope failure.

The International Bathymetric Chart of the Arctic Ocean (IBCAO) Version 3.0

The International Bathymetric Chart of the Arctic Ocean (IBCAO) released its first gridded bathymetric compilation in 1999. The IBCAO bathymetric portrayals have since supported a wide range of Arctic science activities, for example, by providing constraint for ocean circulation models and the means to define and formulate hypotheses about the geologic origin of Arctic undersea features. IBCAO Version 3.0 represents the largest improvement since 1999 taking advantage of new data sets collected by the circum‐Arctic nations, opportunistic data collected from fishing vessels, data acquired from US Navy submarines and from research ships of various nations. Built using an improved gridding algorithm, this new grid is on a 500 meter spacing, revealing much greater details of the Arctic seafloor than IBCAO Version 1.0 (2.5 km) and Version 2.0 (2.0 km). The area covered by multibeam surveys has increased from ∼6% in Version 2.0 to ∼11% in Version 3.0.

An improved bathymetric portrayal of the Arctic Ocean: Implications for ocean modeling and geological, geophysical and oceanographic analyses

A digital representation of ocean floor topography is essential for a broad variety of geological, geophysical and oceanographic analyses and modeling. In this paper we present a new version of the International Bathymetric Chart of the Arctic Ocean (IBCAO) in the form of a digital grid on a Polar Stereographic projection with grid cell spacing of 2 × 2 km. The new IBCAO, which has been derived from an accumulated database of available bathymetric data including the recent years of multibeam mapping, significantly improves our portrayal of the Arctic Ocean seafloor.

Prognostic map of the sedimentary cover thickness for the East Siberian Sea based on satellite altimetry data

Due to its geographic position and climatic conditions, the East Siberian Sea shelf is the least studied passive continental margin of Russia. The shelf area makes up about 10 6 km 2 , and its seismic study involves only individual profiles with a total length of a few thousand kilometers. Therefore, the observation system does not even correspond to the regional scale. As a direct correlation of seismic data to drilling is unavailable for the region, its interpretation is based on indirect information and wave field characteristics used in seismostratigraphy [2, 6‐8]. The high hydrocarbon potential of the region requires new approaches to the reliable assessment of the sedimentary cover thickness (SCV) for the whole region and compilation of a tectonic map. This work elucidates an approach to solution of the problem in a semiquantitative form (with a low appraised accuracy) based on remote methods. Such information involves satellite altimetry data recalculated into the free-air gravity anomaly for the polar region [9]. The coverage accuracy makes up 7.5 mGal, which is sufficient for solving regional problems. The free-air anomaly recalculated into the Bouguer anomaly using topographic data of the International Bathymetric Chart of the Arctic Ocean (IBCAO) is presented in Fig. 1. The Bouguer anomaly virtually does not differ from the free-air anomaly for the shelf area, but its high values suggest the proximity of the dense mantle substrate to the ocean and continental slope beyond the shelf. Taking into account the weak (compared to the deep-water part of the profile) effect, the behavior of the Bouguer anomaly on the shelf generally reflects the topography of the most contrasting and closest density boundary of the crust. Such an interface represents the top of the acoustic basement. The correlation of values of the gravity anomaly and the basement top depth is used for the quantitative prediction of the interface position in the absence of direct seismic data. Such a prediction involves, as a rule, construction of the model implying the relationship between the basement depth H (or SCT) and the anomaly ∆ G representing a simple linear dependence. The dependence is calculated by the correlation of real structural data with the anomalous field for regions located in the neighborhood or presumably exhibiting a similar structure. Later, in the case of direct seismic observations, the model can be corrected or the neces

A Comparison Between GEBCO Sheet 5.17 and the International Bathymetric Chart of the Arctic Ocean (IBCAO) Version 1.0

In 1979, the General Bathymetric Chart of the Oceans (GEBCO) published Sheet 5.17 in the Fifth Edition of its series of global bathymetric maps. Sheet 5.17 covered the northern polar region above 64° N, and was for long the authoritative portrayal of Arctic bathymetry. The GEBCO compilation team had access to an extremely sparse sounding database from the central Arctic Ocean, due to the difficulty of mapping in this permanently ice covered region. In the past decade, there has been a substantial increase in the database of central Arctic Ocean bathymetry, due to the declassification of sounding data collected by US and British Navy nuclear submarines, and to the capability of modern icebreakers to measure ocean depths in heavy ice conditions. From these data sets, evidence has mounted to indicate that many of the smaller (and some larger) bathymetric features of Sheet 5.17 were poorly or wrongly defined. Within the framework of the project to construct the International Bathymetric Chart of the Arctic Ocean (IBCAO), all available historic and modern data sets were compiled to create a digital bathymetric model. In this paper, we compare both generally and in detail the contents of GEBCO Sheet 5.17 and version 1.0 of IBCAO, two bathymetric portrayals that were created more than 20 years apart. The results should be helpful in the analysis and assessment of previously published studies that were based on GEBCO Sheet 5.17.

Global topography and bathymetry grid improves research efforts

Gridded data of topography and bathymetry of the Earth's surface have become widely available via the Internet, thanks to the efforts of multiple research groups, including, for example, the U.S. Geological Survey (http://edcwww.cr.usgs.gov/landdaac/gtopo30/gtopo30.html), Smith and Sandwell [1997], and Jakobsson et al. [2000]. These data are of continually growing importance both for monitoring operations and for scientific research, as they are critical for the clear presentation of final results to end‐users.Nevertheless, in general, for a given region of the world, there is a final step in assembling all the necessary sub‐regions into a continuous grid that represents the area of interest. Also, one must account for the varying resolutions of the component data sets. These issues are surmountable, though painstaking.Three publicly available gridded data sets of topography and bathymetry have been combined to produce a single, integrated data set with no loss in resolution.The 3 data sets are the GTOPO30 data from the U.S. Geological Survey the Global Bathymetry data set from Smith and Sandwell [1997],and version 1.0 of the International Bathymetric Chart of the Arctic Ocean (IBCAO) data set [Jakobsson et al., 2000]. Results are provided as eight GMT grid files covering −180° to +180° longitude and −90° to 90° latitude. To facilitate ease of use without loss of resolution, all data have been sampled and merged into identically registered 30‐s grids. The actual resolutions of the topography and bathymetry data are roughly 30 arc s (0.66 km at 45° latitude) and 2 arc min (2.6 km at 45° latitude), respectively Results are made available free of charge via internet through the Geographic Information Network of Alaska (GINA). The Web address for this server is http://www.gina.alaska.edu/page.xml?group=data&page=griddata.

Physiographic provinces of the Arctic Ocean seafloor

The International Bathymetric Chart of the Arctic Ocean (IBCAO) grid model has been used to define the first-order physiographic provinces of the Arctic Ocean, which in this study is taken to consist of the oceanic deep Arctic Ocean Basin; the broad continental shelves of the Barents, Kara, Laptev, East Siberian, and Chukchi Seas; the White Sea; and the narrow continental shelves of the Beaufort Sea and the Arctic continental margins of the Canadian Arctic Archipelago and northern Greenland. The first step in this classification is an evaluation of seafloor gradients contained in a slope model that was derived from the IBCAO grid. The evaluation of this slope model, which emphasizes certain process-related seafloor features that are reflected in the bathymetric information, is subsequently used along with the bathymetry to classify the first-order physiographic provinces. The areas of the provinces so classified are individually calculated, and their morphologies are subsequently discussed in the context of the geologic evolution of the Arctic Ocean Basin as described in the published literature. In summary, this study provides a physiographic classification of the Arctic Ocean seafloor according to the most up-to-date bathymetric model, addresses the geologic origin of the prominent features, and provides area computations of the defined first-order physiographic provinces and of the most prominent second- order features.

Hypsometry and volume of the Arctic Ocean and its constituent seas

This paper presents an analysis of the Arctic Ocean and its constituent seas for seafloor area distribution versus depth and ocean volume. The bathymetry from the International Bathymetric Chart of the Arctic Ocean (IBCAO) is used together with limits defining this ocean and its constituent seas from the International Hydrographic Organization (IHO) as well as redefined limits constructed to confine the seas to the shallow shelves. IBCAO is a bathymetric grid model with a resolution of 2.5 × 2.5 km, which significantly improved the portrayal of the Arctic Ocean seafloor through incorporation of newly released bathymetric data including echo soundings from U.S. and British navies, scientific nuclear submarine cruises, and icebreaker cruises. This analysis of seafloor area and ocean volume is the first for the Arctic Ocean based on this new and improved portrayal of the seafloor as represented by IBCAO. The seafloor area and volume are calculated for different depths starting from the present sea level and progressing in increments of 10 m to a depth of 500 m and in increments of 50 m from 550 m down to the deepest depth within each of the analyzed seas. Hypsometric curves expressed as simple histograms of the frequencies in different depth bins and depth plotted against cumulative area for each of the analyzed seas are presented. The area and volume calculations show that the entire IHO‐defined Arctic Ocean makes up ∼4.3% of the total ocean area but only ∼1.4% of the volume. Furthermore, the IHO Arctic Ocean is the shallowest (mean depth 1201 m) of all the major oceans and their adjacent seas. The continental shelf area, from the coasts out to the shelf break, make up as much as ∼52.9% of the total area in the Arctic Ocean, defined in this work as consisting of the oceanic deep Arctic Ocean Basin; the broad continental shelves of the Barents, Kara, Laptev, East Siberian, Chukchi, and Beaufort Seas; the White Sea; and the narrow continental shelf off both the Canadian Arctic Archipelago and northern Greenland. This result indicates that the Arctic Ocean has significantly larger continental shelves compared with all the other oceans, where previous studies show that the proportion of shelves, from the coasts out to the foot of the continental slopes, only ranges between about 9.1 and 17.7%. Furthermore, the derived hypsometric curves show that most of the Arctic Ocean shelf seas besides the Barents Sea, Beaufort Sea, and the shelf off northern Greenland have a similar shape, with the largest seafloor area between 0 and 50 m. The East Siberian and Laptev seas, in particular, show area distributions concentrated in this shallow depth range, and together with the Chukchi Sea they form a large flat shallow shelf province composing as much as 22% of the entire Arctic Ocean area but only 1% of the volume. This implies that the circulation in the Arctic Ocean might be very sensitive to eustatic sea level changes. One of the aims with this work is to make up‐to‐date high‐resolution area and volume calculations for the Arctic Ocean at various depths available for download.