NASA - Kristen Walbolt
1. Earth’s changing cryosphere
This year, NASA will launch two satellite missions that will increase
our understanding of Earth’s frozen reaches. Snow, ice sheets,
glaciers, sea ice and permafrost, known as the cryosphere, act as
Earth’s thermostat and deep freeze, regulating temperatures by
reflecting heat from the Sun and storing most of our fresh water.
2. GRACE-FO: Building on a legacy and forging ahead
The next Earth science satellites set to launch are twins! The identical
satellites of the GRACE Follow-On mission will build on the legacy of
their predecessor GRACE by also tracking the ever-changing movement of
water around our planet, including Earth’s frozen regions.GRACE-FO, a
partnership between NASA and the German Research Center for Geosciences
(GFZ), will provide critical information about how the Greenland and
Antarctic ice sheets are changing. GRACE-FO, workingtogether, will
measure the distance between the two satellites to within 1 micron (much
less than the width of a human hair) to determine the mass below.
Greenland has been losing about 280 gigatons of ice per year on
average, and Antarctica has lost almost 120 gigatons a year with
indications that both melt rates are increasing. A single gigaton of
water would fill about 400,000 Olympic-sized swimming pools; each
gigaton represents a billion tons of water.
3. ICESat-2: 10,000 laser pulses a second
In September, NASA will launch ICESat-2, which uses a laser
instrument to precisely measure the changing elevation of ice around the
world, allowing scientists to see whether ice sheets and glaciers are
accumulating snow and ice or getting thinner over time. ICESat-2 will
also make critical measurements of the thickness of sea ice from space.
Its laser instrument sends 10,000 pulses per second to the surface and
will measure the photons’ return trip to satellite. The trip from
ICESat-2 to Earth and back takes about 3.3 milliseconds.
4. Seeing less sea ice
Summertime sea ice in the Arctic Ocean now routinely covers about 40
percent less area than it did in the late 1970s, when continuous
satellite observations began. This kind of significant change could
increase the rate of warming already in progress and affect global
weather patterns.
5. The snow we drink
In the western United States, 1 in 6 people rely on snowpack for
water. NASA field campaigns such as the Airborne Snow Observatory and
SnowEx seek to better understand how much water is held in Earth’s snow
cover, and how we could ultimately measure this comprehensively from
space.
6. Hidden in the ground
Permafrost – permanently frozen ground in the Arctic that contains
stores of heat-trapping gases such as methane and carbon dioxide – is
thawing at faster rates than previously observed. Recent studies suggest
that within three to four decades, this thawing could be releasing
enough greenhouse gases to make Arctic permafrost a net source of carbon
dioxide rather than a sink. Through airborne and field research on
missions such as CARVE and ABoVE – the latter of which will put
scientists back in the field in Alaska and Canada this summer – NASA
scientists are trying to improve measurements of this trend in order to
better predict global impact.
7. Breaking records over cracking ice
Last year was a record-breaking one for Operation IceBridge, NASA’s
aerial survey of polar ice. For the first time in its nine-year history,
the mission carried out seven field campaigns in the Arctic and
Antarctic in a single year. In total, the IceBridge scientists and
instruments flew over 214,000 miles, the equivalent of orbiting the
Earth 8.6 times at the equator.
On March 22, NASA completed the first IceBridge flight of its spring
Arctic campaign with a survey of sea ice north of Greenland. This year
marks the 10th Arctic spring campaign for IceBridge. The flights
continue until April 27 extending the mission’s decade-long mapping of
the fastest-changing areas of the Greenland Ice Sheet and measuring sea
ice thickness across the western Arctic basin.
8. OMG
Researchers were back in the field this month in Greenland with
NASA’s Oceans Melting Greenland survey. The airborne and ship-based
mission studies the ocean’s role in melting Greenland’s ice. Researchers
examinetemperatures, salinity and other properties of North Atlantic
waters along the more than 27,000 miles (44,000 km) of jagged coastline.
9. DIY glacier modeling
Computer models are critical tools for understanding the future of a
changing planet, including melting ice andrising seas. A new
NASA sea level simulator
lets you bury Alaska’s Columbia glacier in snow, and, year by year,
watch how it responds. Or you can melt the Greenland and Antarctic ice
sheets and trace rising seas as they inundate the Florida coast.
10. Ice beyond Earth
Ice is common in our solar system. From ice packed into comets that
cruise the solar system to polar ice caps on Mars to Europa and
Enceladus—the icy ocean moons of Jupiter and Saturn—water ice is a
crucial ingredient in the search for life was we know it beyond Earth.
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