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Articles 1 - 10 of 10
Full-Text Articles in Physical Sciences and Mathematics
Observations Of Backscatter From Sand And Gravel Seafloors Between 170-250 Khz, Thomas C. Weber, Larry G. Ward
Observations Of Backscatter From Sand And Gravel Seafloors Between 170-250 Khz, Thomas C. Weber, Larry G. Ward
Center for Coastal and Ocean Mapping
Interpreting observations of frequency-dependence in backscatter from the seafloor offers many challenges, either because multiple frequencies are used for different observations that will later be merged or simply because seafloor scattering models are not well-understood above 100 kHz. Hindering the understanding of these observations is the paucity of reported, calibratedacoustic measurements above 100 kHz. This manuscript seeks to help elucidate the linkages between seafloor properties and frequency-dependent seafloor backscatter by describing observations of backscatter collected from sand, gravel, and bedrock seafloors at frequencies between 170 and 250 kHz and at a grazing angle of 45°. Overall, the frequency dependence appeared …
Initiatives In Using Crowdsourcing, Satellite Derived Bathymetry, And Other Non-Traditional Hydrographic/Bathymetric Measurements, Anthony Klemm, Shachak Pe'eri, John Nyberg
Initiatives In Using Crowdsourcing, Satellite Derived Bathymetry, And Other Non-Traditional Hydrographic/Bathymetric Measurements, Anthony Klemm, Shachak Pe'eri, John Nyberg
Center for Coastal and Ocean Mapping
No abstract provided.
Reconnaissance Surveying Using Satellite-Derived Bathymetry, Shachak Pe'eri, Patrick Keown, Michael Gonsalves
Reconnaissance Surveying Using Satellite-Derived Bathymetry, Shachak Pe'eri, Patrick Keown, Michael Gonsalves
Center for Coastal and Ocean Mapping
False Pass, AK, USA, is the eastern-most passage through the Aleutian Islands between the Bering Sea and the Pacific Ocean and provides a passage for small to mid-size vessels. The passage is considered an alternative route to Unimak Pass, AK for vessels from mainland Alaska and is estimated to be shorter by 160 to 240km. False Pass is closed every winter due to sea-ice cover that freezes the inlet system around OctoberNovember and melts only towards the spring (around March). As a result, the soft sediment of the seafloor contains mud and sand that may change the path of the …
Chart Adequacy: Workshop And Gebco Training, Limor Gur-Arieh, Yusoff Kamaruddin, Amon Kimeli, Anthony Klemm, Hirokazu Kurita, Shachak Pe'eri, Indra Budi Prasetyawan, Jae-Young Roh, Jaya Roperez, Nilupa Samarakoon, Jaqueline Sydenham, Maxlimer Vallee, Rochelle A. Wigley
Chart Adequacy: Workshop And Gebco Training, Limor Gur-Arieh, Yusoff Kamaruddin, Amon Kimeli, Anthony Klemm, Hirokazu Kurita, Shachak Pe'eri, Indra Budi Prasetyawan, Jae-Young Roh, Jaya Roperez, Nilupa Samarakoon, Jaqueline Sydenham, Maxlimer Vallee, Rochelle A. Wigley
Center for Coastal and Ocean Mapping
In July, 2015 the first NOAA Chart Adequacy Workshop was held in Silver Spring, Maryland, USA. Following a three-day workshop (14th to 16th July, 2015), four Nippon Foundation GEBCO students stayed at NOAA for an additional 10-day training at Office of Coast Survey’s Marine Chart Division. The key objective of the NOAA Chart Adequacy Workshop was to demonstrate techniques to evaluate the suitability of nautical chart products using chart quality information and publicly-available information. The attendees were cartographers, hydrographers and potential chart producers from hydrographic offices and government agencies around the world. The nations of the participants in the workshop …
Reconnaissance Surveying Of Bechevin Bay, Ak Using Satellite-Derived Bathymetry, Shachak Pe'eri, Patrick Keown, Leland P. Snyder, Michael Gonsalves, John Nyberg
Reconnaissance Surveying Of Bechevin Bay, Ak Using Satellite-Derived Bathymetry, Shachak Pe'eri, Patrick Keown, Leland P. Snyder, Michael Gonsalves, John Nyberg
Center for Coastal and Ocean Mapping
Recently, a remote sensing study has been conducted over Bechevin Bay Channel, Alaska as part of a collaboration project between NOAA and the U.S. Coast Guard (USCG). The goal of the study to develop a procedure to prioritize survey areas and plan the annual deployment of Aids to Navigation (AtoN) along the channel. Bechevin Bay is considered a priority for marine surveying because it constitutes the easternmost passage through the Aleutians from the Bering Sea to the Gulf of Alaska. The channel is located in a mud flat area, where every winter the passage is closed due to ice cover. …
Multibeam Mapping Of Feature Rich Seafloor In The U.S. Pacific Remote Islands Marine National Monument And On Mendocino Ridge Off The California Coast, Andy Armstrong, James V. Gardner, Brian R. Calder, Giuseppe Masetti
Multibeam Mapping Of Feature Rich Seafloor In The U.S. Pacific Remote Islands Marine National Monument And On Mendocino Ridge Off The California Coast, Andy Armstrong, James V. Gardner, Brian R. Calder, Giuseppe Masetti
Center for Coastal and Ocean Mapping
No abstract provided.
S-100 Overlays: A Brave New World?, Lee Alexander, C. Mcleay
S-100 Overlays: A Brave New World?, Lee Alexander, C. Mcleay
Center for Coastal and Ocean Mapping
Marine Information Overlay (MIO) is a generic term used to describe chart and navigation related information that supplement the content that is already contained in an ENC. This includes both static and dynamic information such as tide/water level, current flow, meteorological, oceanographic, and environmental protection. With the advent of S-100 and S-101, there is increased interest in providing a wide variety of ‘new’ overlay information. This paper provides a brief history of S-57 MIOs. Examples of navigational and non-navigation MIOs are given in terms of how currently used, by who, and for what purpose. Recommendations are provided for making a …
Nautical Chart Adequacy Evaluation Using Publicly-Available Data, Anthony Klemm, Shachak Pe'eri, Ricardo Freire, John Nyberg, Shep M. Smith Lt
Nautical Chart Adequacy Evaluation Using Publicly-Available Data, Anthony Klemm, Shachak Pe'eri, Ricardo Freire, John Nyberg, Shep M. Smith Lt
Center for Coastal and Ocean Mapping
The International Hydrographic Office (IHO) C-55 publication communicates the need to improve the collection, quality and availability of hydrographic data world-wide, while also monitoring and rectifying possible deficiencies and shortcomings that are presented on the chart. This task of evaluating the adequacy of nautical chart products poses a challenge to many national hydrographic offices. This stems from the dearth of readily available spatial information: namely, the lack of reliable and accessible vessel traffic data, and little means to assess the changing nature of both near-shore bathymetry and shoreline in a simple and reliable manner. In this paper, we present the …
Euclidean Reconstruction Of Natural Underwater Scenes Using Optic Imagery Sequence, Han Hu
Euclidean Reconstruction Of Natural Underwater Scenes Using Optic Imagery Sequence, Han Hu
Center for Coastal and Ocean Mapping
The development of maritime applications require monitoring, studying and preserving of detailed and close observation on the underwater seafloor and objects. Stereo vision offers advanced technologies to build 3D models from 2D still overlapping images in a relatively inexpensive way. However, while image stereo matching is a necessary step in 3D reconstruction procedure, even the most robust dense matching techniques are not guaranteed to work for underwater images due to the challenging aquatic environment. In this thesis, in addition to a detailed introduction and research on the key components of building 3D models from optic images, a robust modified quasi-dense …
Arctic Ocean Bathymetry: A Necessary Geospatial Framework, Martin Jakobsson, Larry A. Mayer, Dave Monahan
Arctic Ocean Bathymetry: A Necessary Geospatial Framework, Martin Jakobsson, Larry A. Mayer, Dave Monahan
Center for Coastal and Ocean Mapping
Most ocean science relies on a geospatial infrastructure that is built from bathymetry data collected from ships underway, archived, and converted into maps and digital grids. Bathymetry, the depth of the seafloor, besides having vital importance to geology and navigation, is a fundamental element in studies of deep water circulation, tides, tsunami forecasting, upwelling, fishing resources, wave action, sediment transport, environmental change, and slope stability, as well as in site selection for platforms, cables, and pipelines, waste disposal, and mineral extraction. Recent developments in multibeam sonar mapping have so dramatically increased the resolution with which the seafloor can be portrayed …