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Temporal gravity field variations from oceanic, atmospheric and inner core mass redistributions and their sensitivity to new gravity missions CHAMP and GRACE
| Content Provider | Semantic Scholar |
|---|---|
| Author | Reigber, Ch. Barthelmes, Franz Greiner-Mai, Hans Gruber, Th. Jochmann, Horst Wuensch, Johann |
| Copyright Year | 1999 |
| Abstract | Temporal gravity field variations are caused by mass redistributions in the atmosphere, on the Earth's surface and in the Earth's interior. With the upcoming new gravity missions CHAMP and GRACE, for the first time such variations can be measured from space on a global scale. To estimate the time variable gravity signals and their sensitivity to the new missions, simulation studies for specific gravity variation sources in all three areas are performed. Starting from a long series of monthly mean atmospheric air pressure data from 1900 to 1988, monthly atmospheric density variations with respect to the long-term mean are computed and transformed into monthly gravity coefficients. A similar approach was used to estimate monthly gravity field coefficients from oceanic mass redistributions. For an 8-year period, monthly spherical harmonic series up to degree and order 6 from ocean bottom pressure fields, derived from the POCM ocean circulation model, are estimated. Another method for estimating the impact of ocean mass redistributions on the gravity field is based on three-year monthly residual sea-surface models from altimetry, which are corrected for the thermal water expansion. Attraction of these residual water masses is transformed into monthly gravity field coefficients up to degree and order 100. Finally, gravity changes caused by the precession of the inner with respect to the outer core and their density differences are predicted for a long time series from 1900 to 1991. Half-yearly gravity coefficients are estimated up to degree 2. Time series for all gravity field coefficients from these different sources are then analyzed to detect their amplitudes and phase lags. All calculated gravity signals are compared to the expected sensitivity of the CHAMP and GRACE missions. |
| Starting Page | 329 |
| Ending Page | 340 |
| Page Count | 12 |
| File Format | PDF HTM / HTML |
| Volume Number | 40 |
| Alternate Webpage(s) | http://www3.ogs.trieste.it/bgta/pdf/bgta40.3.4_REIGBER2.pdf |
| Language | English |
| Access Restriction | Open |
| Content Type | Text |
| Resource Type | Article |
