Although a lot of people have their reserves, GRACE’s star seems on the rise.
GRACE is the name of two satellites which orbit the earth, the one following the other. The Earth’s gravity field pulls the satellites towards earth, constantly slightly changing their distance to earth. The second satellite registers the movements of the first, and so in this way the gravity field of earth can be calculated.
Now, it is said that with GRACE one can monitor changes in groundwater storage. However, there are a lot of factors one still needs to filter out of the orriginal GRACE data. This is the reason why there is also a lot of scepticism about GRACE’s reliability for such exercises.
The following article reports on the work of Famiglietti of Irvine University, California. Famiglietti analysed monthly data for 6 years of GRACE data (2002 – 2008) and found startling results concerning India’s groundwater reserves. read more at sciencedaily.com