Ocean circulation, changes of ground water levels and soil moisture, melting of continental ice sheets, river discharge, sea level changes and convective flow in the Earth mantle, all this causes transport and re-distribution of masses.
Using innovative and extremely precise sensor systems, dedicated gravity field and altimeter satellite observe the implication of these processes. The integrated analysis of these observation data shall improve the knowledge about these processes within the system Earth.
The Deutsche Forschungsgemeinschaft (DFG) therefore established the priority program "Mass transport and mass distribution in the system Earth" (2007 - 2012). The program requires integrated approaches which can be realized only by an interdisciplinary analysis and modelling of data.
This Web site informs about content and results of the priority program.
Der Abschlußbereicht des DFG-Schwerpunktprogramms "Massentransporte und Massenverteilung im System Erde (SPP 1257)" ist jetzt online verfügbar.
Der 2. Sonderband (Special Issue) des SPP Massentransporte ist jetzt im Journal Surveys in Geophysics als Vol.6 erschienen.
13 interdisziplinäre Teams haben hier noch einmal herausragende Ergebnisse veröffentlicht.
River discharge on a global scale is one of the essential inputs (“musts”) for any global scale description of the water balance on the land masses and in the atmosphere and their interaction and also serves as one of the driving forces for ocean circulation. Despite their immeasurable importance the number of river gauging stations has been permanently decreasing worldwide since the 1970s and has nearly decreased by 50 percent since then. Modelling of river discharge does not solve the problem as it is flawed with very big uncertainties. Thus there is an exceeding necessity for spaceborne methods, which allow to measure river discharge and thus overcome possible technical or political constraints in the future.
A recent study on the relationship between measured river discharge on the one hand and liquid water storage measured by the gravity satellite GRACE and remote sensing on the other hand now opens up new possibilities to determine river discharge from space directly. [more]
FRANKFURT.In what parts of the world and to what degree have groundwater reservoirs been depleted over the past 50 years? The Frankfurt hydrologist Prof. Petra Döll has been researching this using the global water model WaterGAP. She has arrived at the most reliable estimate to date by taking into consideration processes which are important in dry regions of the world. The values calculated were compared with monitoring data from many different wells and data from the GRACE satellites. These satellites measure changes in the Earth's gravity field. Döll has come to the conclusion that the rate at which groundwater reservoirs are being depleted is increasing, but that the rate is not as high as previously estimated. [more]
Recent research has shown that decadal changes in net Mediterranean Sea evaporation have characterized the 1960-2010 period, with an overall increase in net evaporation resulting in a substantial increase in sea-surface water loss. [more]
FRANKFURT. WaterGAP (Water Global Assessment and Prognosis) is a hydrological model used to model water shortage, groundwater depletion, and floods and droughts (e.g. as impacted by climate change) over the land area of the globe. The Frankfurt hydrologist Prof. Petra Döll has examined how good a fit this model provides, using GPS observations and data from the GRACE satellite, which measures the gravitational field of the Earth. The study, published in the current issue of the scientific journal Surveys in Geophysics indicates that WaterGAP needs to be modified. [more]
The SPP1257 will organize a summer school on "GRACE/GRACE-FO applications for the terrestrial water cycle", September 15-19, 2014. More information will be provided soon.
Preparation of the second special issue on mass transport and mass distribution in the system Earth, is well on its way. About 15 SPP-teams submitted their latest findings to this issue, to appear in Surveys of Geophysics.
Das Sonderheft des SPP Massentransporte bei Journal of Geodynamics ist jetzt verfügbar.
Link zu Sciencedirect
No life without water. Catastrophes like droughts or strong rains reflect our dependence on the water cycle and climate system. Hence, it is important to understand details of the water cycle among the atmosphere, oceans, and land. A study in the Journal of Hydrometeorology now outlines significant differences of global models and measurement data sets. As the network of measurement stations worldwide is shrinking dramatically, uncertainties are increased. [ more ... ]
The joint GRACE Science Team Meeting (GSTM) and Final Colloquium of the DFG Special Priority Program (SPP1257) "Mass Transport and Mass Distribution in the System Earth" will take place at the German Research Centre for Geosciences (GFZ) in Potsdam, Germany on September 17-19, 2012. Further information (registration, abstract upload, draft program) can be found here.
The meeting will be followed by a one day Sea Level Workshop (September 20) organized by the German National Academy of Sciences (Leopoldina) and the SPP1257. Further information can be found here.
Am 12.-16. September 2011 fand in Mayschoss im Ahrtal bei Bonn die Sommerschule zum Thema "Globaler Wasserkreislauf" statt. Während der Sommerschule wurde von Uni Bonn TV ein Beitrag über die Veranstaltung gedreht.
The lecture material from the Mayschoss summer school 2011 can be downloaded here.
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Let's face it, understanding the concept of 'geocenter motion' is not for the faint-hearted. On a good day it is only confusing, while on bad days we would rather avoid the subject all together. The story below is meant to clear the fog somewhat for those of you who have more bad days than good days. We additionally provide links to recently calculated geocenter motion time series, for those of you who want to get started with real data. [ more ... ]
When comparing the Earth’s geoid with a shear velocity anomaly map of the lowermost mantle, a clear spatial correlation between the positive geoid anomalies over Africa and the Pacific (Figure 1, top) and the location of Large Low Shear Velocity Provinces (LLSVPs) in the lowermost mantle (Figure 1, bottom) can be established. [ more ... ]
We classified different plume types in terms of their geoid signals. These calculations have been done using a Finite Element convection code in axi-symmetric spherical shell geometry, where the plumes developed at the pole. We ran simulations of sixteen different viscosity distributions for three different Rayleigh numbers. They illustrate scenarios where hot plumes have a larger or smaller influence on the geoid and topography compared to the constant viscosity case. We now are able to define different classes of plumes by classifying their geoid signals. [ more ... ]
Tides play an important role in the evaluation of satellite missions; they influence the altimetry and change the gravity fields due to short-term variations in the sea level and the associated loading effect on the sea floor. This effect causes aliasing in determining the geoid and in observing ice thickness, for example, on the Antarctica and on the Greenland. [ more ... ]
For the first time, a dedicated release of the hydrology and water use model WaterGAP3, tailored to the basins draining into the Mediterranean and Black Sea, has been set up and applied within the STREMP project. WaterGAP3 calculates all water fluxes (e.g. runoff, evapotranspiration) and water storage compartments (e.g. groundwater, snow storage) on a 5 arc minute grid (~6x9 km). Additionally, within the WaterGAP3 modelling framework five water use models for the sectors households, irrigation, livestock, electricity production, and manufacturing industries have been further developed and applied to account for extensive water abstractions in the region. Within the SPP1257 WaterGAP3 model output is being used to correct the estimation of water mass change for hydrology leakage on land and to account for freshwater inflow into both oceans. [ more ... ]
The SPP1257 would like to draw your attention to the session G5.3 that will take place during the next EGU meeting in Vienna 03 Apr 2011 - 08 Apr 2011. Please submit your abstracts online before 10 January 2011, 24:00, the deadline for receipt of abstracts. To submit an abstract, follow the link in the session description page: meetingorganizer.copernicus.org/EGU2011/session/6495
Contact: Johannes Riegger (Johannes.Riegger@iws.uni-stuttgart.de), Tonie van Dam (firstname.lastname@example.org), Jürgen Kusche (email@example.com)
For the first time daily gravity field snapshots have been derived from GRACE level 1B data using a Kalman smoother approach. When calculating independent solutions, such an extreme increase in temporal resolution would lead to a loss in redundancy and therefore to a decreasing accuracy of the estimated parameters with decreasing time span. [ more ... ]
The new gravity field model ITG-Grace2010 has recently been released. It was calculated at Bonn University from 7 years of GRACE level 1B observations (2002-08 – 2009-08) and consists of three parts: daily solutions calculated using a Kalman smoother, unconstrained monthly solutions, and a high-resolution long-time mean. [ more ... ]
Glacial isostatic adjustment (GIA) describes the deformations of the solid earth which are induced by loading of the ice sheets repeatedly covering large areas in North America and Europe during the Pleistocene (last few Myr). [ More ... ]
Terrestrial gravity observations from superconducting gravimeters (SG) contain fundamental information on mass transfer especially related to hydrology. They offer the unique opportunity to supplement and validate the time-dependent gravity field variations derived from the GRACE satellite mission. [More…]
Up to now, short-period mass transport processes, like continental hydrology and ocean dynamics, have been studied using individual datasets. Information from multiple datasets can however be combined to obtain more accurate estimates of mass transport and improve our knowledge of ocean and land processes. [ More... ]
Analyzing nearly 15 years of altimeter data from different satellite missions a new global ocean tide model has been generated, providing amplitudes and phases for major diurnal and semi-diurnal constituents (K1, O1, Q1, M2, N2, S2, K2, 2N2) and the non-linear M4 tide on a dense 7.5'x7.5' geographical grid. [ More... ]
After the successful launch of ESA’s gravity satellite GOCE on March 17 from the northern Russian Cosmodrome Plesetsk, GOCE’s highly sensitive gradiometer instrument has been switched on and is stably producing meaningful data. [ More... ]
Analyzing more than 7 years of GRACE data has provided a completely new view on the Earth's changing gravity field and on the processes causing these changes. A new algorithm has been developed which allows reducing noise ('stripes') in GRACE solutions, and identifying signals of smaller scale than thought possible before. [ More... ]
The twin GRACE satellites observe the time varying gravity field caused by the sum of all mass variations within the Earth system. It has now been proven that the integral GRACE observations can be separated by means of empirical orthogonal functions derived from geophysical models and that mass variations within the individual subsystems ocean, atmosphere and continental hydrosphere can be distinguished and quantified. [ More... ]