GRACE is an oceanographic satellite sensor, developed to help get ocean mass distributions and hence geostrophic oceanic flows. It very accurately measures the mass below the sensor from gravitational pull variations . This is used to accurately determine oceanic geostrophic flow.
It also determines the shape of the geoid. This means the sensor has good money support, since an accurate geoid is necessary for long range missile accuracy. It means the military wants to classify the data and restrict access.
Nevertheless, the GRACE data (put up March, 2002) has been made available and I heard an interesting result at the Oceans from Space meeting in Venice. In the eight years of data, the mass of the oceans has been increasing, while the mass of the Antarctic has been decreasing. Of course this corresponds with global warming predictions – the ice is melting into the oceans. Just another data point.
Some commenters will say, there I go, pushing global warming. But I would have reported it just as readily if the measurement had been the opposite. In fact it would have been more interesting, as non-GW forces are looking desperately for data, and contrary data is always more interesting. But it is not so, just more boring GW indicators.