From the Helmholtz Association of German Research Centres evidence that maybe, just maybe, climate has become a singularity unto its own, and everything now in the physical world is “climate”. Or…they’ve jumped the shark. The headline of this press release is mind-blowingly stupid.
‘Gravity is climate’ – 10 years of climate research satellites GRACE
How much ice is Greenland is really losing? – Movement in the Earth’s mantle? – Enough water for all?
For the first time, the melting of glaciers in Greenland could now be measured with high accuracy from space. Just in time for the tenth anniversary of the twin satellites GRACE (Gravity Recovery and Climate Experiment) a sharp image has surface, which also renders the spatial distribution of the glacial melt more precisely. The Greenland ice shield had to cope with up to 240 gigatons of mass loss between 2002 and 2011. This corresponds to a sea level rise of about 0.7 mm per year.
These statements were made possible by the high-precision measurements of the GRACE mission, whose data records result in a hitherto unequaled accurate picture of the earth’s gravity.
One of Newton’s laws states that the gravity of an object depends directly on its mass. “When the mass of the Greenland ice sheet changes, so does the gravity there,” explains Dr. Frank Flechtner from the GFZ German Research Centre for Geosciences. “The GRACE gravity field measurements therefore give us information on mass changes, including climate-related ones.”
But there’s more. The uneven distribution of mass on and within the planet causes, due the resulting variability of gravity, the earth to have an irregular shape, which deviates significantly from sphericity. Known as the “Potsdam Gravity Potato, the geoid has achieved global notoriety. But this potato shape is equally subject to temporal changes. During the last Ice Age, a mile-thick ice sheet covered North America and Scandinavia. Since the ice melted, the crust, now liberated from its load, continues to rise to this day. This causes material flow in the earth’s interior, in the mantle, to replenish. With GRACE, this glacial-isostatic adjustment can for the first time be accurately detected globally as a change in the geoid height: the ice ages continue to have an effect, which is especially evident in North America and Scandinavia.
Anniversary in space
On 17 March 2012, the two GRACE twin satellites will have been in orbit for exactly 10 years. The scientists named them “Tom and Jerry”, because they chase each other on exactly the same orbit around the earth. Since their launch from the Russian cosmodrome in Plesetsk, the two satellites have circled the Earth more than 55 000 times on a near polar orbit at about 450 to 500 km altitude and a distance of 220 km, and continuously collected data.
GRACE is a joint project of the U.S. space agency NASA and the German Aerospace Center (DLR). The mission was planned in 1996 by the GFZ German Research Centre for Geosciences, the University of Texas Center for Space Research (UTCSR) and the Jet Propulsion Laboratory in Pasadena, and in 1997 was selected to be the second mission in NASA’s program Earth System Science Pathfinder (ESSP). The scientific analysis of the data is carried out jointly by GFZ, UTCSR and JPL. Principal Investigator of the mission is Prof. Byron Tapley (UTSCR), Co-Principal Investigator is Dr. Frank Flechtner (GFZ). Especially noteworthy: with GRACE, NASA for the first time commissioned a non-American company to build satellites. Astrium in Friedrichshafen, who built the GFZ’s founding father satellite CHAMP (Challenging Mini-satellite Payload), produced the satellite duo GRACE for NASA.
A hair’s breadth: gravity field measurements with satellite
The primary scientific goal of the GRACE satellite mission is to measure the gravitational field of the earth and its changes over time on a global scale with unprecedented accuracy. If the earth were a homogeneous sphere, the two satellites would orbit at exact elliptical orbits around the Earth. But the uneven distribution of mass causes perturbations in the trajectory. “Their analysis allows us to derive the irregular structure of the Earth’s gravity,” explains Dr. Frank Flechtner. “This, however, requires the satellites’ orbits to be measured with high precision. Each of the two GRACE satellites is therefore equipped with a GPS receiver for positioning, an accelerometer to correct for disturbing forces due to the residual atmosphere and solar radiation, and two star trackers to determine the satellites’ position in space.” But the core is the ultra-precise distance measurement system developed by NASA / JPL, which allows the separartion of the two satellites to be continuously measured with a precision of one tenth of a hair’s breadth.
From the varying distance between the two satellites, GFZ scientists can determine the gravitational field of the earth. Approximately every 30 days, the satellite pair has collected enough data for a complete global map. This monthly survey of gravity is at least 100 times more accurate than any previous model, and thus invaluable for the research at the GFZ and the international user community. “Many processes in the climate of our planet are accompanied by large-scale water mass redistributions, which are made visible in the gravitational field,” adds Flechtner. This enabled, as the name of the mission suggests, the first observation and analysis of homogeneous and globally numerous climate-related processes from the monthly gravity field models over the last 10 years. Particularly worth mentioning are
- The mass balance study of the continental water content, which is ultimately a sum of precipitation, evaporation, runoff and storage. GRACE monitors the season-dependent changes in the major river basins, but also the huge groundwater extraction due to irrigation in northern India and California.
- Quantification of the increase or decrease of the ice and snow masses in the polar or large glacier areas. GFZ scientists were able to demonstrate a strong correlation between the climatic phenomenon ENSO / La Nina, the rainfall patterns in West Antarctica and the reduction of ice mass there.
- The observation of surface and deep currents, which – in combination with the sea surface topography derived from satellite altimetry – brought about a much better understanding of the global ocean circulation and thus the heat transport from the equator toward the poles.
- The first-time possibility of separation of mass (ice melt) or temperature (global warming) induced sea level changes.
- The changes in the solid earth after large earthquakes, such as Sumatra-Andaman (2004), Chile (2010) and Fukushima (2011).
New potatoes and improved weather forecast
The ‘Potsdam Gravity Potato’, originally developed in 1995, is now much more precise thanks to GRACE. This is not a gimmick, but is required, for example, to improve the trajectories of geodetic satellites and derive accurate global reference systems from them – a prerequisite for the combination and evaluation of various global sensor systems such as the Global Positioning System (GPS), Satellite Laser Ranging (SLR), the satellite altimetry or local gauge measurements such as for the observation of sea level rise. Another scientific objective of the GRACE mission is to derive about 150 globally distributed vertical temperature and water vapor profiles from GPS data on a daily basis. These data reach the GFZ via its own receiving station in Ny Ålesund (Spitsbergen) and are delivered to the global weather centers within 2 hours to improve global forecasts. In addition, these data are used for studies of climate induced changes in the earth’s atmosphere.
A scientific birthday gift
Right from the beginning, GRACE was planned to be an international program. “For the 10th Birthday, the researchers have devised a special gift for the more than 3,000 users”, says Professor Reinhard Huettl, Chair of the Board of the GFZ. “The entire mission was recalculated with improved correction models, instrument data and processing standards.” Initial analyzes show that the accuracy of gravity field models could be further improved by a factor of 2. These new models will be released to the global users on 17 March via the Information System and Data Centre (ISDC) of the GFZ.
Like its predecessor mission CHAMP (Challenging Mini-Satellite Payload), GRACE will on 17 March be running for twice as long as originally planned. An end of the mission is, however, still in sight. Therefore, the GFZ have initiated a follow-up mission together with the U.S. colleagues. Professor Hüttl is confident: “We hope that at Christmas 2016 two GRACE-FO (follow-on) satellites will orbit around the Earth, because only long time series can provide reliable information on global trends in climate.”
Images in printable resolution can be found here:
http://www.gfz-potsdam.de/portal/gfz/Public+Relations/M40-Bildarchiv/Bildergalerie_Kartoffel
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I can’t find the story on their site; I’d bet, however, it made more sense in German.
REPLY: Yeah I was thinking that too, but this is Eurekalert. You’d think they’d check it – Anthony
Actually a superb achievement, the mission is wonderful science.
The more egregious comments reflect the normal rent seeking behavior common to federally funded scientists, it is considered good form to have your project produce conclusions consistent with the national policy of the day.
As long as the raw data is not adjusted out of recognition and then discarded, there will be useful results eventually.
“When the mass of the Greenland ice sheet changes, so does the gravity there,” explains Dr. Frank Flechtner from the GFZ German Research Centre for Geosciences. “The GRACE gravity field measurements therefore give us information on mass changes, including climate-related ones.”
When the mass of the ice sheet changes the gravity changes, but does that necessarily guarantee that when GRACE measures a change in gravity it is necessarily measuring a change in ice sheet mass?
“This corresponds to a sea level rise of about 0.7 mm per year.”
This is what is really vapid …. exactly what HASN’T been observed …. by anyone or anything actually measuring sea level.
Jeez.
Actually take that back … I mis-read 0.7mm as 7mm….. whoops.
Once more you reveal your complete ignorance of what is going on, and how scientists are working that out. Changes in gravity are indeed telling us about the climate changes – in Greenland, Antarctica, Alaska and elsewhere.
Indeed, only last month you were lauding a study based on GRACE that showed minimal net losses in the Himalayas.
So what is it to be? excellent tool for assessing trends in ice and water movements, or those crazy scientists jumping sharks? Or are we simply seeing knee jerk reactions to whatever gets into your RSS feed?
Yes, “ein Orbitalschwerpunktkartoffelverarbeitendenmaschine” is a useful device.
Gravity is absolutely the ideal parameter for post-rational scienc-ey types to measure and interpret.
First, it’s quantifiable (Hey, man, it’s DATA) and it can be measured with meaningless precision
Second, the interpreters can sound soooo important by saying “It’s, like, one of the Fundamental Laws of Nature, man! It’s the Physics”
Third, changes in gravitational attraction can be caused by myriad things (any change in mass distribution), none of which is unique nor uniquely verifiable. The interpretation depends ENTIRELY on data reduction and MODELING.
So GRACE data can be used to conclude ANYTHING
Perfect. GRACE can probably detect butterfly wing-beats and forecast the effects around the globe.
Nice article. Couple of ‘typos’:
”
How much ice is Greenland is really losing? ”
Is is ?
”
For the first time, the melting of glaciers in Greenland could now be measured with high accuracy from space. Just in time for the tenth anniversary of the twin satellites GRACE (Gravity Recovery and Climate Experiment) a sharp image has surface, which ”
Perhaps “surfaced“?
When you look at the “Cryosphere” section of the IPCC’s draft AR5 documents due for publication if 2013 you will find several studies of the rate of ice loss world wide. Even with the help of the GRACE, the measurements cover a broad range of values.
For argument’s sake let me suppose that the highest number is correct, in which case the ice is melting at a rate of 285 Gt/year. That sounds like a really scary number until you put it in context. The current “Ice Inventory” for the planet averages ~3 million Gt. If the present rate of loss continues we could be rid of all permanent ice cover in 10,000 years.
While much of the science in the WG1 drafts is first rate, the summary completely fails to put things in context leaving the door open for alarmist interpretations being delivered in the “Summary for Policy Makers”.
Those who would pick our pockets want the money now rather than in a thousand years so they exaggerate the dangers by orders of magnitude.
@JPW:
Oh please. “Gravity is Climate” is a jump the shark headline or just lousy copy that’s sensationalized. “Gravity can inform some small bits about climate variation” is a true statement.
Or maybe you want to discuss “what is is”…
O/T but here goes. plenty of critical quotes :
16 March: Post Crescent/USA Today: AP: Susan Montoya Bryan: NM regulators scrap carbon emissions rules
New Mexico regulators pulled the plug Friday on the state’s effort to reduce greenhouse gas emissions among coal-fired power plants, refineries and other large polluters.
The Environmental Improvement Board adopted a repeal petition filed last year by utilities and industry groups that were concerned about rising costs and New Mexico’s economic viability.
The vote marks the second time in two months that the board has undone regulations passed in the waning weeks of former Democratic Gov. Bill Richardson’s administration that were aimed at curbing carbon emissions…
The board found that the regulations were not justified, that they violated New Mexico law because they were more stringent than what the federal government requires and that the state’s adoption of federal permitting rules had actually triggered a sunset clause related to the greenhouse gas emissions regulations.
Environmentalists said the federal permitting rules, which have been placed on hold by the Obama administration, won’t do enough to curb emissions.
Last month, the Environmental Improvement Board also scraped rules that would have cleared the way for New Mexico to participate in a regional cap and trade program…
http://www.postcrescent.com/usatoday/article/38820927?odyssey=mod%7Cnewswell%7Ctext%7CFRONTPAGE%7Cp
That nice lumpy graphic of the Earth’s gravity field illustrates very well the futility of all our lengthy arguments about millimeter scale variations in GMSL. If you look at a map of the Geoid, which represents the surface of the world’s oceans with everything except gravity variations excluded
http://en.wikipedia.org/wiki/File:Geoid_height_red_blue_averagebw.png
you will note that the difference in “absolute” surface height between that blue spot in the Indian Ocean basin and the big bulge north of Australia is almost 200 meters just across that relatively short span of the globe. ( I put quotes around absolute since it is fundamentally impossible to know the ocean height in that way because no baseline reference for it exists). In reality the seas are never level and any changes to their volume, whether from steric changes or from volume added by melting ice, will never be reflected uniformly across the planet.
“On 17 March 2012, the two GRACE twin satellites will have been in orbit for exactly 10 years.”
========================
Mark Twain –
– There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.
———-
Some more:
– Always do right. This will gratify some people and astonish the rest.
– When we remember we are all mad, the mysteries disappear and life stands explained.
lol, yes such precision…. let’s see….. ice melt measured by Grace….. there was a study just published which used Grace to measure the Himalayan glacier melt…… precisely showed a mass loss of only 4 ± 20 Gt yr−1…… let’s not start pretending they can measure sea-level to 1/10ths of a mm. That precision is derived by “fun with numbers.”.
making it up as they go along, as usual:
17 March: Stuff New Zealand: Forestry carbon trading in limbo
Some foresters are reported to have sold their credits for a lucrative sum.
But at the moment, things are in limbo.
Carbon prices have plummeted, due partly to the global downturn and to cheap credits from overseas driving down the local price…
However, with the carbon price falling from $21 in April last year to less than $8 today, the trading scheme has all but ground to a halt.
David Rhodes says that needs addressing.
***”We will be hoping they … will alter the rules sufficiently where we end up in a situation where the carbon price is not as volatile as it has been and investors have a much more secure basis for deciding whether they’re going to get in,” he said…
http://www.stuff.co.nz/business/industries/6590067/Forestry-carbon-trading-in-limbo
So with the currant rate of mass loss in a bit less than 120 thousand years it’s all gone.
We better start moving to higher ground immediately.
the pressure is starting to pay off. don’t back down:
15 March: Reuters: UPDATE 2-UN aviation body hit by carbon emissions dispute
* Working group to evaluate options, report in June
* To consider role of developing countries
* Under pressure to find alternative to EU scheme
The news came as sources said China was suspending the purchase of 10 more Airbus jets, escalating a trade row over airline emissions.
In a decision obtained by Reuters, the council instructed a working group to continue its study of “market-based measures” to deal with aviation emissions and report back at the next council meeting, scheduled for June.
It also asked the working group to evaluate whether the measures being studied can “accommodate the special circumstances and respective capabilities of developing countries”.
The official said a large majority of the council voted for the decision, including China, Russia, the United States, and the European members…
A coalition of more than 20 countries, including China, Russia and the United States, has been organized to oppose the EU scheme, arguing the plan infringes on their sovereignty…
The European Commission has said it was forced to act alone after ICAO failed to come up with a viable plan. It said it will modify its law if the ICAO comes up with an acceptable alternative.
(Additional reporting by Barbara Lewis in Brussels; Editing by Janet Guttsman and Peter Galloway)
http://www.reuters.com/article/2012/03/15/airlines-emissions-idUSL2E8EF1Y320120315
This reminds me of Luboš Motl’s blog post showing why sea level in Iceland would drop if Greenland ice melted.
http://motls.blogspot.ca/2010/06/if-greenland-melted-sea-level-in.html
gallopingcamel says:
March 16, 2012 at 8:13 pm
“The current “Ice Inventory” for the planet averages ~3 million Gt.”
I believe that number is a serious underestimate. By my admittedly rough calculation there is over 20 million Gts in the Antarctic icecap alone. Approx 15mil km2 land area X 90% ice cap coverage X 1.7 km average depth = 20+km3 of ice. As I recall 1km3 = 1Gt.
Look into the Isostatic adjustment (glacial rebound). Smith et al used GPS mounted on bare rock to calculate the adjustment but was rejected because it showed an increase in the ice, (more gained in the center than lost on the rim). Velegona (sp?) et al used a modeled isostatic ajustment to come up with the politicly correct answer. The funny part is, they used data from the precipitation models in thier model.
if this is true, Greenland must have an enormous Schwanzstuker!
Gravity changes can not prove ice melting, because there are gravity changes also in places, where there is no ice and nothing has changed on the surface.
I have said this before – GRACE can only detect mass changes, not the source of the mass change. There is no, repeat ‘no’, way for anyone tie changes in the Earth’s gravity field to melting ice.
Take it for the NASA Systems Engineer with a quarter of a century of experience. GRACE only knows something between the center of the Earth and it’s orbit altitude changed. Nothing more.