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

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