NASA’s New Studies of Earth’s Seas, Skies, and Soils

They’re carbonated, salty, and alternately wet and dry.
Exotic champagnes? No, they’re NASA’s three Earth System
Science Pathfinder small-satellite program missions: Orbiting
Carbon Observatory, Aquarius and Hydros.

NASA has awarded all three of these fine “wines” gold medals of
sorts by authorizing them to proceed with mission formulation.
Each mission performs a first-of-a-kind exploratory measurement
that will help answer fundamental questions about how our
planet works and how it may change in the future. The Orbiting
Carbon Observatory will enhance our understanding of Earth’s
carbon cycle and climate. Aquarius will examine the way oceans
affect and respond to climate change. Hydros will study how
water, energy and carbon are exchanged between land and Earth’s
atmosphere.

“These three innovative missions have demonstrated they are
ready to use state-of-the-art remote sensing technology to
observe and help us understand the cycles of water, energy and
carbon through Earth’s system. These are essential ingredients
for sustaining life on Earth, and NASA is using the power of
space technology to understand them,” said Dr. Ghassem Asrar,
NASA’s associate administrator for Earth Science. “NASA plans
to negotiate contract awards for these low-cost missions that
address key scientific questions regarding how Earth’s
atmosphere, oceans and land work together to shape our weather,
climate and environment,” he said.

The Orbiting Carbon Observatory’s two-year mission is targeted
for launch in August 2007. It will provide the first global,
space-based measurements of atmospheric carbon dioxide. The
measurements will have the precision to identify and monitor
human and natural processes responsible for absorbing and
emitting this important greenhouse gas, a fundamental building
block for food, fiber and life on Earth.

Precise ground-based measurements, collected since the 1970s,
indicate only about half of the carbon dioxide emitted into the
atmosphere by fossil fuel combustion has remained there. The
land and oceans have apparently absorbed the rest. However,
ground-based measurements are not adequate to determine how or
where this absorption is occurring. These uncertainties
compromise our ability to predict future atmospheric carbon
dioxide concentrations or their effect on the climate system.

Dr. David Crisp of NASA’s Jet Propulsion Laboratory, Pasadena,
Calif., is principal investigator for the mission, which
includes more than 19 universities, corporate and international
partners.

Aquarius’s three-year mission, targeted for launch in September
2008, is the first satellite mission specifically designed to
provide monthly global maps of how salt concentration varies on
the ocean surface. Variations in ocean surface salinity are a
key area of scientific uncertainty. Scientists wish to better
understand how these variations modify the interaction between
ocean circulation and the global water cycle, which, in turn,
affects the oceans’ capacity to store and transport heat and
regulate Earth’s climate. The mission seeks to determine how
the ocean responds to the combined effects of evaporation,
precipitation, ice melt and river runoff on seasonal and
interannual time scales, and their impact on the global
distribution and availability of fresh water.

Dr. Gary Lagerloef of Seattle’s Earth and Space Research is the
principal investigator. More than 17 universities, corporate
and international partners will be involved in the mission,
including Argentina’s Comision Nacional de Actividades
Espaciales. NASA will provide the Aquarius salinity sensor,
project management, launch services and science data
processing. Argentina will provide the spacecraft, additional
instruments and mission operations.

Hydros will make unprecedented measurements of Earth’s changing
soil moisture and the freeze/thaw status of land surface that,
together, define the state of Earth’s hydrosphere. This state
links the water, energy and carbon cycles over land. Hydros
measurements will open new frontiers in our understanding of
how these global cycles work together in the Earth system.
Numerical models used for day-to-day weather prediction need
soil moisture estimates as initial conditions for forecasts.
Incorporating real observations into these models will
significantly improve forecast accuracy. Soil moisture is among
the top terrestrial environment measurement requirements of the
Departments of Defense and Transportation because of the impact
on land navigation and aviation weather.

Contributing partners for the Hydros mission, in addition to
NASA, include the Canadian Space Agency and the Department of
Defense. The Hydros science team draws from several
universities, NASA centers, research and operational branches
of federal agencies. The principal investigator is Dr. Dara
Entekhabi of the Massachusetts Institute of Technology,
Cambridge, Mass.