• MODIS Pic of the Day 19 January 2022

    From Dan Richter@1:317/3 to All on Wed Jan 19 11:00:44 2022
    January 19, 2022 - Ash Plume over Australia

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    On January 15, 2022, the island nation of Tonga was rocked by a
    monumental eruption of the Hunga Tonga-Hunga Ha’apai volcano. The
    immensely powerful explosion could be heard from New Zealand to Alaska,
    and it sent tsunami waves across the entire Pacific basin. Waves of
    over 3 feet (0.9m) were recorded in Alaska, while two people were
    reported to have died along the coast of Peru and two injured in Japan
    due to the effect of tsunami. Three people have died in Tonga, but
    estimation of casualties and damage are very rudimentary on the islands
    near Hunga Tonga-Hunga Ha’pai because of near-complete loss of internet
    and ability to communicate.

    The eruption also flung a massive amount of ash, gas, and steam high
    into the stratosphere, creating an umbrella-like cloud that spread
    across the region. Data collected on January16 by the Cloud-Aerosol
    Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission,
    shows ash and gas from the eruption rising to an altitude of 31
    kilometers (19 miles). CALIPSO is a joint mission of NASA and France’s
    National Centre for Space Studies (CNES).

    The thick ash has created substantial aviation hazards. It has delayed
    reconnaissance flights aimed at assessing damage of Tonga’s islands as
    well as largely obscured the islands from satellite view. Although
    limited, imagery and overflights reveal a very thick layer of ash lying
    atop nearby islands as well as structural damage affecting coastal
    towns on several of Tonga’s islands. The large amount of ash raises
    health concerns, including potential respiratory problems and
    contamination of wells used for drinking water. Volcanoes often emit
    sulfur dioxide, a substance that can cause severe respiratory distress
    in both people and animals.

    Since the January 15 eruption, the volcanic ash and gas has not stayed
    stationary, but has spread over the region. By January 16, a thick
    blanket of ash and gas reached Australia, where it continues to spread.
    On January 17, The Moderate Resolution Imaging Spectroradiometer
    (MODIS) on board NASA’s Terra satellite acquired a true-color image of
    volcanic ash blanketing the Coral Sea as well as Queensland and
    Northern Territory, Australia. Even though the ash cloud had travelled
    more than 5,000 km (3,100 miles), it was still so thick that it
    obscured the land from view in many locations.

    The bright white streak of cloud seen over the Gulf of Carpentaria and
    Papua New Guinea is not caused by ash. It is part of an optical
    phenomenon known as sunglint. This occurs when sunlight reflects off
    the surface at the same angle that a satellite sensor views it. The
    result is a mirror-like reflection of sunlight off the water or cloud
    and back at the satellite sensor. Sunglint is often seen as a silver
    color in water but, in this case, the sunlight reflects strongly from
    the cloud to create a bright white streak.

    Image Facts
    Satellite: Terra
    Date Acquired: 1/17/2022
    Resolutions: 1km (2.4 MB), 500m (6.8 MB), 250m (4.3 MB)
    Bands Used: 1,4,3
    Image Credit: MODIS Land Rapid Response Team, NASA GSFC



    https://modis.gsfc.nasa.gov/gallery/individual.php?db_date=2022-01-19
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