نتایج جستجو برای: Satellite gravity

تعداد نتایج: 141432  

Journal: :فیزیک زمین و فضا 0
a safari department of surveying and geomatics engineering, university college of engineering, university of tehran, tehran, iran m.a sharifi department of surveying and geomatics engineering, university college of engineering, university of tehran, tehran, iran h amin department of surveying and geomatics engineering, university college of engineering, university of tehran, tehran, iran i foroughi department of surveying and geomatics engineering, university college of engineering, university of tehran, tehran, iran

gravity acceleration data have grand pursuit for marine applications. due to environmental effects, marine gravity observations always hold a high noise level. in this paper, we propose an approach to produce marine gravity data using satellite altimetry, high-resolution geopotential models and harmonic splines. on the one hand, harmonic spline functions have great capability for local gravity ...

ژورنال: فیزیک زمین و فضا 2014
A Safari H Amin I Foroughi M.A Sharifi

Gravity acceleration data have grand pursuit for marine applications. Due to environmental effects, marine gravity observations always hold a high noise level. In this paper, we propose an approach to produce marine gravity data using satellite altimetry, high-resolution geopotential models and harmonic splines. On the one hand, harmonic spline functions have great capability for local gravity ...

Journal: :فیزیک زمین و فضا 0
عبدالرضا صفری یعقوب حاتم مهدی شاه حیدری

precise geoid determination on islands suffers from the lack of accurate gravity data on the open seas. nowadays, sub-microgal accuracy for the land gravity observations is obtainable. but the sea gravity data which are collected via shipborne techniques, due to the measuring environment at sea area, are usually highly noisy and are contaminated with various systematic errors. on the other hand...

Estimating the gravity anomaly causative bodies boundary can facilitate the gravity field interpretation. In this paper, 2D discrete wavelet transform (DWT) is employed as a method to delineate the boundary of the gravity anomaly sources. Hence, the GRACE’ satellite gravity data is decomposed using DWT. DWT decomposites a single approximation coefficients into four distinct components: the appr...

Journal: :international journal of environmental research 2012
s.m.t. sadatipour r. kiamehr m. abrehdary a.r. sharifi

one of the difficulties in using absolute altitudes is the separation between the mean open sealevel and geoid. theoretically, geoid is the base level in absolute altitudes, but practically, the mean open sealevel is used as a base level for absolute altitudes. the difference between these two levels is called as the seasurface topography. in this research, it is dealt the mean sea level modeli...

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...

Journal: :international journal of environmental research 0
s.m.t. sadatipour islamic azad university, north tehran branch, department of hydrography, tehran, iran r. kiamehr university of zanjan,division of cartography, zanjan, iran m. abrehdary royal institute of technology, division of geodesy and geomatics, stockholm, sweden a.r. sharifi islamic azad university, north tehran branch, department of hydrography, tehran, iran

one of the difficulties in using absolute altitudes is the separation between the mean open sealevel and geoid. theoretically, geoid is the base level in absolute altitudes, but practically, the mean open sealevel is used as a base level for absolute altitudes. the difference between these two levels is called as the seasurface topography. in this research, it is dealt the mean sea level modeli...

Journal: :فیزیک زمین و فضا 0
عبدالرحیم عسکری استادیار، دانشگاه تربیت معلم سبزوار وحید ابراهیم زاده اردستانی دانشیار، گروه فیزیک زمین، مؤسسة ژئوفیزیک دانشگاه تهران و قطب علمی مهندسی نقشه برداری و مقابله با سوانح طبیعی علیرضا آزموده اردلان استاد، گروه مهندسی نقشه برداری، قطب علمی مهندسی نقشه برداری در مقابله با سوانح طبیعی، پردیس دانشکده های فنی

measuring field gravity in sea due to the accelerations introduced via waves and movements to the gravity measuring systems has a low accuracy since according to einstein's equalent principle, gravimeter isn't able to separate the gravity acceleration from another acceleration. ship borne gravimetery observations by means of like oscillations and accelerations of the ship motion, and ...

Journal: :فیزیک زمین و فضا 0
عبدالرحیم عسکری وحید ابراهیم زاده اردستانی علیرضا آزموده اردلان

changing altimetry information from satellites on the surface of seas and oceans, into anomaly gravity for example free air anomaly, is a fundamentally new method presented by researches. the determination of the free air gravity anomaly over the earth’s marine regions has led to a major improvement in our understanding of plate tectonic processes relating to oceanic ridges, the formation of ma...

Chegini , Nabiollah, Kiani Shahvandi, Mostafa , Nazari, Borzoo , Safari , Abdolreza ,

In this paper, a method is proposed for producing gravity acceleration at sea surface in the Persian Gulf. This method is based on the Geoid height from satellite altimetry, high resolution Geopotential models, and ellipsoidal splines. First, the definition of the ellipsoidal spline functions is presented in a Hilbert space, which is consisted of infinitely often differentiable functions. In or...

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