 |
| Titel |
Secular Change of the Geoid Geopotential Value, W0, from Sea Level Measurements and GRACE |
| VerfasserIn |
Nadim Dayoub, Philip Moore, Nigel Penna, Stuart Edwards |
| Konferenz |
EGU General Assembly 2010
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250036684
|
|
|
|
|
|
| Zusammenfassung |
| Current accuracy of satellite geodetic techniques enables investigation of the time variation of
the fundamental geodetic parameter W0 as a response to sea level change and mass
redistribution etc. In this study, we use two approaches to estimate the temporal variability of
W0 : (i) a regional approach which utilizes tide gauge (TG) and co-located continuous GPS
data to recover the annual geodetic coordinates of mean sea level at TG sites. By referencing
these coordinates to a high resolution geopotential model such as EGM2008, the annual
geopotential values are recovered, from which the secular trend of W0 is estimated. We use a
minimum of 30 years of TG records and around 10 years of CGPS observations from
nine sites in the UK and one in France. The CGPS time series enable estimation
of the GIA and other geological signals at the TG sites and therefore an absolute
sea level trend can be estimated. (ii) A global approach, in which radar altimetry
provides a direct measure of the sea surface on a sub-monthly basis, for example,
approximately every 10 days from TOPEX/Poseidon. Accordingly, a time series of global
sea level measurements can be established. In addition, the GRACE mission is
sensing the variation within the Earth’s gravity field up to degree 60 in terms of
spherical harmonics. Herein, data between 2002 and 2008 are used from JASON-1
and GRACE to recover monthly values of W0 which are used to infer the secular
trend of the geoid geopotential. The influence of geocenter variation on W0 is also
investigated.
Keywords: Tide gauge, continuous GPS, JASON-1, GRACE |
|
|
|
|
|
|