Researchers will design a mission to learn about underground aquifers in areas such as the Sahara and how climate change will affect them in the future.
Earth’s driest
ecosystems are a study in extremes: They can be blazingly hot stretches of sand
like the Sahara Desert or shatteringly cold expanses of ice such as those in Greenland
and Antarctica. These arid regions receive very little annual precipitation,
and the effects of climate change in these ecosystems are poorly understood. A
joint effort between NASA and the Qatar Foundation aims to address that – and,
in the process, help communities that are being impacted by those changes.
Researchers
with the Orbiting Arid Subsurfaces and Ice Sheet Sounder (OASIS) study project
are designing a satellite mission to probe the sand dunes and ice sheets of
some of Earth’s driest places with radar technology similar to that used by
NASA’s Mars Reconnaissance Orbiter (MRO). The project’s primary goal would
be to discover and monitor underground sources of fresh water called aquifers. Many
aquifers in the deserts of North Africa and the Arabian Peninsula, among
others, are being rapidly depleted to support the needs of local communities.
At the same
time, aquifers in coastal regions are being threatened by sea level rise caused
by the melting of ice sheets in places like Greenland. If the saltwater from
rising seas contaminates the fresh water in aquifers, it would affect not only drinking
water but also regional agriculture and food security. A secondary goal of the
project is to gain a better understanding of how melting ice sheets contribute
to rising seas.
Under a
reimbursable Space Act Agreement with NASA and the Qatar Foundation (QF) for
Science, Education & Community Development – represented by Hamad Bin
Khalifa University (HBKU) and the Qatar Environment and Energy Research
Institute (QEERI) at HBKU – NASA’s Jet Propulsion Laboratory and QEERI will
jointly formulate a mission concept study for Qatar’s prospective OASIS
mission.
The OASIS project seeks to study fresh water aquifers in the desert as well as ice sheets in places like Greenland. This illustration shows what a satellite with a proposed radar instrument for the mission could look like. Image Credit: NASA/JPL-Caltech
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Searching
the Desert
The project
seeks to put a satellite in Earth orbit to map the distribution of shallow aquifers
beneath the desert’s surface in North Africa and the Arabian Peninsula.
Scientists plan to use the satellite’s radar instrument to study how those
aquifers originated and how groundwater moves beneath the deserts through a
complex system of subsurface fractures that spread out like a spiderweb between
aquifers. Data collected in the process would help with aquifer management.
“The scientific community is excited about
this mission. OASIS would be the first spaceborne radar specifically designed
to detect directly subsurface water on Earth,” said James Graf, director for Earth Science and
Technology at JPL in Southern California.
Project researchers also
intend to study the topography of the land under ice sheets in Greenland and
Antarctica to determine such properties as ice sheet thickness and the pathways
by which ice flows to the ocean. This information could feed into models of
current and future ice sheet responses to climate change, which would help
researchers better understand ice sheet contributions to sea level rise.
“Warm and
cold deserts are responding to climatic changes by expanding and shrinking,
respectively,” said Essam Heggy, the OASIS principal investigator and
chief scientist and research program director of the Earth Science Program at
QEERI. “Studying the forces driving these transformations will give us
insight into the evolution of deserts on Earth.”
In a decadal survey identifying
Earth science areas of focus between 2017 and 2027, the National Academies of
Sciences noted that gaining a better understanding of these arid regions was
one of several priorities.
“The 2017 National
Academies Decadal Survey for Earth Science and Applications from Space
identified a need to understand aquifer dynamics and ice sheet contributions to
sea level rise. The OASIS study project will explore a promising complementary
observing approach that can contribute to our understanding about these two
areas of Earth science research,” said Gerald Bawden, NASA program
scientist for the OASIS project.
Signal
Return
Led by Artur Chmielewski,
the OASIS study project manager at JPL, and Heggy, the project’s team will
design a spaceborne mission that uses radar technology similar to that
developed for MRO to explore beneath the Martian surface. The instrument under
consideration for the OASIS project, a 50 megahertz sounding radar, is expected
to see through up to 1.8 miles (3 kilometers) of ice and nearly 330 feet (100
meters) of sand.
The radar
signal is sensitive to changes in the electrical properties beneath Earth’s
surface caused by rocks, sediments, waterlogged soils, ice, pools of water, and
the like. Some of these substances absorb more of the signal than others. Researchers
look at how much of the signal bounces back to the instrument, as well as how
long the signal takes to return, in order to develop a picture of what a
particular area looks like beneath the surface.
In a 2011 proof-of-concept
mission, researchers flew a helicopter over two well-known freshwater aquifers beneath
Kuwait’s deserts to ensure a radar sounding instrument could detect them. They conducted
several similar flights over other deserts in Oman and Morocco. The OASIS study
project will expand the scope of those initial efforts for a more global
picture.
“Water
security is becoming a global issue for an increasing number of countries
around the globe and beyond the so-called arid regions,” said Marc
Vermeersch, the executive director of the Qatar Environment and Energy Research
Institute. “This project is pioneering the research in this field by
providing Qatar – and the whole scientific community – an innovative tool that will
bring key responses in the field, support the decision-making process in terms
of water resources, and help identify pathways to secure access to water for
populations. I am particularly glad and proud QEERI is teaming up with NASA for
the sake of a better world, and for the advancement of science.”
Researchers and
engineers on the OASIS study project will spend the next two years formulating
the mission concept.
To learn more
about NASA’s study of Earth’s changing climate, visit:
News Media Contact
Jane J. Lee / Ian J. O’Neill
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0307 / 818-354-2649
jane.j.lee@jpl.nasa.gov / ian.j.oneill@jpl.nasa.gov
2020-185
Source: Jet Propulsion Laboratory