Ask Dr. Bryan Killett About Climate Change and GRACE 122
Bryan Killett is a physicist working on the Gravity Recovery And Climate Experiment (GRACE) for NASA's Jet Propulsion Laboratory. GRACE is a joint mission of NASA and the German Aerospace Center which collects satellite data to learn about Earth's changing gravity field, specifically the high frequency changes associated with ocean tides. As the high tide comes in, more water is present, so gravity in that location is temporarily strengthened. These changes are detected with GRACE and used to improve ocean tide models. Dr. Killett provides the open source (GPLv3) code used to process GRACE data on his home page. Bryan has agreed to take a break from measuring gravity fields and answer your questions about GRACE and the climate changes it has revealed. Feel free to ask as many as you like but please confine your questions to one per post.
Melting ice (Score:4, Informative)
GRACE's main use in climate change is to detect the loss of mass from melting glaciers (mostly in Greenland and Antarctica), which results in sea level rise. It can also help map surface currents in the ocean, and track the motion of water through the hydrological cycle.
NASA expertise [Re:Climate Change] (Score:4, Informative)
I'll ask the opposite question: why shouldn't aeronautical engineers, astrophysicists, and rocket scientists be involved in trying to make unambiguous measurements of a critical issue, to try to resolve key questions in a way that's independent of computer models or temperature measurements? Making an independent measurement of key scientific claims using a different technique is pretty much the gold standard of science.
Because it's not their field of expertise.
Precision measurements of the gravity field of the Earth using spacecraft? It most certainly is their field of expertise.
Because they should be focusing on what my tax dollars pay them to do - develop methods for space exploration and explore space.
Here is the wording of the Space Act of 1958, which established NASA and listed its mission and objectives. After declaring that NASA will be a civilian agency to undertake aeronautical and space activities of the U.S. "for the benefit of all mankind," it states: ..."
"The aeronautical and space activities of the United States shall be conducted so as to contribute materially to one or more of the following objectives:
(1) The expansion of human knowledge of the Earth and of phenomena in the atmosphere and space. (2)
Expanding human knowledge of the Earth and phenomena in the atmosphere: yes, the GRACE objectives fit into the mission that NASA is explicitly instructed to do.
Reference: http://history.nasa.gov/spaceact-legishistory.pdf [nasa.gov]