Measuring Impact of Climate Change from Space: Gravity Measurements Shed Light on Key Questions

[n2doc]

ScienceDaily (Dec. 10, 2009) — What is the impact of climate change on the ice-covered regions of Earth? How does deglaciation affect global sea level changes?

Global mass variations from August 2002 to July 2008 as observed by the GRACE satellite mission. Negative signals dominate over Greenland, Alaska and Antarctica, mainly resulting from ice melting. (Credit: University of Stuttgart)



These questions are being addressed by scientists from the Institute of Geodesy at the University of Stuttgart, Germany, and the Department of Spatial Science at the Curtin University of Technology in Perth, Australia. For this purpose, the German-Australian team has been investigating space-borne gravity measurements provided by the GRACE satellite mission.
As a result, they have found out that the Greenland glaciers shrunk continuously in the last few years; above all, they estimated the changes not to be linear in time but accelerating. On average, recent Greenland ice-mass decline caused an annual sea-level rise of about 0.5 millimetres.
For the first time ever, the GRACE satellite mission has allowed the determination of global mass variations -- such as ice melting in the polar areas -- from changes in Earth's gravitational pull. The underlying measurement principle is simple: it is based on the fact that the redistribution of masses on the Earth surface can be mapped in terms of changes of the terrestrial gravity field. Hence, scientists can measure the spatio-temporal variations of Earth's gravitational attraction on a test mass in space, namely the GRACE spacecraft. From these observations they can derive surface mass-variation patterns.
The satellite data clearly reveal that the Greenland area exhibits the main dominant mass shrinkage over the whole globe. It is predominantly caused by the persistent melting of the Greenland glaciers. Presently, the Arctic island loses between 165 and 189 cubic kilometres ice a year. This estimate is considerably higher than the results derived from geometric satellite measurements conducted in the 1990s.

more:

http://www.sciencedaily.com/releases/2009/12/091209194242.htm

[orwell]

1. But what about those e-mails?

Climategate! Bad science! Cooked data!

Nevermind... :eyes: