Transcript GRACE - Monterey Bay Aquarium Research Institute (MBARI)

GRACE
Gravity Recovery and Climate Experiment
Matt Malina
8/2/07
GRACE
• Launched March, 2002
• 2 twin satellites that measure the earth’s
gravitational field
How does it work?
• 2 twin satellites fly one in front of the other
• The lead one is deflected when itgoes
over an area of the earth with a different
gravity field.
• GRACE 1 & 2 can detect a change in
distance between them up to 1 micron!
• They circle the earth 16 times per day
• Complete a full map of the earth’s gravity
once per month.
What areas of research does it
help?
• Oceanography
• Climate change
• Hydrology
Gravity
m1m2G
Force due to gravity 
2
r
Oceanography
GRACE
Direct observation
Other satellite
Climate change
• The Greenland ice sheet has been losing
mass due to global warming
Climate Change cont’d
• Similar effects have been measured in
Antarctica
• It is estimated such melting has lead to
0.4 mm/yr  0.2 in sea level rise
Hydrology
• GRACE can also detect if aquifers are
filling or being depleted
• This is important because…
Hydrology cont’d
• In Western Asia it is estimated that an
underwater aquifer near Uzbekistan is filling at a
rate of 25 km3 of water per year.
• Most of this water is water that was intended for
irrigation but seeped into the soil.
The end