نتایج جستجو برای: gravity acceleration observation and satellite altimetry data

تعداد نتایج: 17078706  

Farzaneh, Saeed, Parvazi, Kamal, Namazi, Bahare , Sharifi, Mohammad Ali ,

Although tidal observations which are extracted from coastal tide gages, have higher accuracy due to their higher sampling rate, installing these types of gages can impose some spatial limitation since we cannot use every part of sea to install them. To solve this limitation, we can employ satellite altimetry observations. However, satellite altimetry observations have lower sampling rate. Acco...

2007
Gregory A. Neumann W. Forsyth David Sandwell

We compare new marine gravity fields derived from satellite altimetry with shipboard measurements over a region of more than 120,000 square kilometers in the central South Atlantic. Newly declassified satellite data were employed to construct free-air anomaly maps on 0.05 degree grids [Sandwell and Smith, 1992; Marks et al., 1993]. An extensive gravity and bathymetry dataset from four cruises a...

2014
SHUANGGEN JIN GUIPING FENG

The Gravity Field and Steady-State Ocean Circulation Explorer (GOCE) and satellite altimetry can provide very detailed and accurate estimates of the mean dynamic topography (MDT) and geostrophic currents in China’s marginal seas, such as, the newest high-resolution GOCE gravity field model GOCONS-GCF-2-TIM-R4 and the new Centre National d’Etudes Spatiales mean sea surface model MSS_CNES_CLS_11 ...

Ali Reza Azmoudeh Ardalan Hassan Hashemi Farahani

Using satellite altimetry derived mean sea level (MSL), geopotential coefficients in terms of ellipsoidal harmonics from recent satellite gravimetry missions, gravity potential values over a grid consisting of 33,486 points at global sea areas are computed and the mean value of the gravity potential at MSL is calculated as a new geoid’s potential value. In this way we have exactly followed the ...

Journal: :فیزیک زمین و فضا 0
عبدالرضا صفری دانشیار، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی، دانشگاه عبدالرحمان مصطفایی دانشجوی دکتری ژئودزی، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی، دانشگاه

height is amongst the most delicate subjects of geodesy. thanks to the global navigation satellite systems (gnss) like gps or glonass, 3d point positioning of points, by geometrical positioning, since years ago has become a common practice. the height derived from these ways has a geometrical concept. in civil projects the physical concept of the height is more demanded. orthometric height, , i...

Journal: :فیزیک زمین و فضا 0
مهروز خادمی کارشناس ارشد ژئودزی، گروه مهندسی نقشه برداری، دانشکده نقشه برداری، دانشگاه صنعتی خواجه نصیرالدین طوسی، تهران، ایران مهدی نجفی علمداری دانشیار، گروه مهندسی نقشه برداری، دانشکده نقشه برداری، دانشگاه صنعتی خواجه نصیرالدین طوسی، تهران، ایران محمدعلی شریفی استادیار، گروه مهندسی نقشه برداری، پردیس دانشکده های فنی، دانشگاه تهران، ایران

the recent dedicated satellite gravimetry missions have provided huge amount of high quality gravity data with global coverage. from computational point of view, estimation of the unknown gravity field parameters is a highly demanding task due to the sheer number of observations and the unknown coefficients. different computational schemes have been proposed to tackle the problem. since the ear...

2011

Thepresentpaper reviews thecontemporary stateofdefinitionand theoryof thegeoid. Key features are: quasigeoid, externalgravitational field from satellites and its analytical downward continuation to the Earth's interior, data combination by least-squares collocation, and a new view of gravity reduction. This is done under the modern systematic perspective provided by the possibility of a purely ...

2013
DAVID SANDWELL EMMANUEL GARCIA

M than 60% of the Earth’s land and shallow marine areas are covered by > 2 km of sediments and sedimentary rocks, with the thickest accumulations on rifted continental margins (Figure 1). Free-air marine gravity anomalies derived from Geosat and ERS-1 satellite altimetry (Fairhead et al., 2001; Sandwell and Smith, 2009; Andersen et al., 2009) outline most of these major basins with remarkable p...

Journal: :نشریه دانشکده فنی 0
علیرضا آزموده اردلان حسن هاشمی فراهانی

using satellite altimetry derived mean sea level (msl), geopotential coefficients in terms of ellipsoidal harmonics from recent satellite gravimetry missions, gravity potential values over a grid consisting of 33,486 points at global sea areas are computed and the mean value of the gravity potential at msl is calculated as a new geoid’s potential value. in this way we have exactly followed the ...

Journal: :فیزیک زمین و فضا 0
حسن هاشمی فراهانی علیرضا آزموده اردلان

gravity recovery and climate experiment (grace) satellite gravimetry mission launched in march 2002 based on its twin gravimetric satellites makes application of both high-low (hl) and law-low (ll) gravimetric techniques possible. the ll is based on satellite-to-satellite tracking (sst) via the one way two frequencies k-band-ranging between the two grace satellites. as a result of combination o...

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