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Tag: Ross Ice Shelf

  • Seen & Heard: FAA updates interference resources, measuring Bangladesh’s highest peak and more

    Seen & Heard: FAA updates interference resources, measuring Bangladesh’s highest peak and more

    Interference clocked by the FAA

    The U.S. Federal Aviation Administration (FAA) has updated its “GNSS Interference Resource Guide.” The FAA’s Flight Technologies and Procedures Division (AFS-400) developed the guide to provide operators and pilots with current information on GPS/GNSS jamming and spoofing. According to the guide, “As the threat of GNSS jamming and spoofing is constantly changing, the FAA will update this resource guide to provide the best guidance in the rapidly changing environments.”

    Download the guide here.

    UK scientists unite to uncover coastline mysteries

    The research vessel Cefas Endeavour at dock in Lowestoft.(Credit: Cefas)
    The research vessel Cefas Endeavour at dock in Lowestoft.(Credit: Cefas)

    The UK Centre for Seabed Mapping (UK CSM) conducted a survey to explore and map the seabed along the United Kingdom’s southwest coastline. For four weeks, a team of 26 maritime scientists collected hydrographic, geological and environmental data. According to UK CSM, the survey represents an unprecedented level of collaboration within the maritime sector. The team aimed to collect and share high-quality marine data and make advances in how the seabed is mapped, understood and managed. The findings will support a wide range of applications including offshore energy and infrastructure, marine ecosystem science, safety at sea, marine policy, and defense.

    Bangladesh at the top

    Credit: MD Maruf Hassan/E+/Getty Images
    Credit: MD Maruf Hassan/E+/Getty Images

    In April, field teams for the Survey department under the Ministry of Defense
    conducted field work in the remote hill areas of Bangladesh to determine the
    highest peak. Surveyors used modern geodetic methods and advanced GNSS
    technology in the Bandarban district, and followed international standards to
    determine the height of the country’s highest peak above mean sea level (MSL)
    with centimeter-level accuracy, including latitude, longitude and elevation.

    Turbulence shrinks Antartica’s Ross Ice Shelf

    Sketch (not to scale) of GNSS sensitivity to atmospheric turbulence in Antarctica. GNSS stations can probe the spatiotemporal distribution of water vapor in the lower atmosphere because water vapor induces a measurable signal propagation delay. Water-vapor distribution is spatially homogeneous for a non-turbulent atmosphere and heterogeneous when the atmosphere is turbulent. (Credit: MIT)
    Sketch (not to scale) of GNSS sensitivity to atmospheric turbulence in Antarctica (Credit: MIT)

    GNSS observations suggest a major melting event at Antarctica’s Ross Ice Shelf was
    linked to atmospheric turbulence. While the shelf typically melts underneath from warm ocean water, an unusual surface melting episode occurred in January 2016. Researchers from MIT Haystack Observatory used data from existing GNSS stations, with 13 stations installed on the shelf, to examine atmospheric turbulence. Wind, water vapor and temperature variations drawn in by warm and humid air caused the surface to melt, with turbulence four times greater than usual.

  • GNSS reveals fourfold turbulence during Antarctica’s Ross Ice Shelf melt

    GNSS reveals fourfold turbulence during Antarctica’s Ross Ice Shelf melt

    Observations suggest a major melting event at the Ross Ice Shelf was connected to atmospheric turbulence.

    The Ross Ice Shelf in Antarctica typically melts on its underside as warmer ocean water flows beneath. But in January 2016, an unusual melting episode occurred on its topside.

    A team from the Massachusetts Institute of Technology (MIT) Haystack Observatory used data from existing GNSS stations, in conjunction with 13 stations installed on shelf, to examine the turbulent state of the atmosphere. Key were delay differences at each station and between stations that showed the strength (or rockiness) of atmospheric turbulence over the ice shelf.

    Wind, water vapor, and temperature variations drawn in by warm and humid air caused the surface to melt, with turbulence four times greater than usual during the 2016 surface melting event.

    The study also demonstrated a novel application of the GNSS station data to remotely observe unusual atmospheric conditions.

    The open-access study was published Feb. 27 in Geophysical Research Letters.