Conforming Falcon^‡ gravity and the global gravity anomaly

Abstract

A B S T R A C TGravity derived only from airborne gravity gradient measurements with a normal error distribution will have an error that increases with wavelength. It is straightforward in principle to use sparsely sampled regional gravimeter data to provide the long wavelength information, thereby conforming the derived gravity to the regional gravity. Regional surface or airborne gravimeter data are not always available and can be difficult and expensive to collect in many of the areas where an airborne gravity gradiometer survey is flown. However the recent release by the Danish National Space Centre of the DNSC08 global gravity anomaly data has provided regional gravity data for the entire earth of adequate quality for this purpose. Studies over three areas, including comparisons with ground, marine and airborne gravimetry, demonstrate the validity of this approach. Future improvements in global gravity anomaly data are expected, particularly as the product from the recently launched Gravity field and steady-state Ocean Circulation Explorer (GOCE) satellite becomes available and these will lead directly to an improvement in the very wide bandwidth gravity available after conforming gravity derived from gravity gradiometry with the global gravity.

Determination of the Strike and the Dip of a Line Source Using Gravity Gradient Tensor

“…이를 극복하기 위하여 최근에 는 벡터 중력을 도입하려는 경향이 있지만 (Krahenbuhl et al, 2014), 벡터 중력계는 아직 상용화 단계가 아 니므로 현장에 적용하기 위해서는 많은 시간이 필요 하다 (Rim and Li, 2013). 반면 중력 변화율 텐서의 측정은 여러 개의 가속도계를 복합적으로 이용하는 중력 변화율 측정 시스템이 개발되어 활발히 이용되 고 있다 (Dransfield, 2010;Lee, 2001). 중력 변화율 텐서는 기본적으로 서로 독립인 5개의 성분이 존재 하므로 중력이나 벡터 중력에 비해 정보의 양이 비 약적으로 증가하므로 이를 응용하려는 다양한 연구들 이 수행되고 있다 (Zhdanov et al, 2004;Beike, 2010;Beike and Pedersen, 2010;Rim and Li, 2012;Martinez et al, 2013;Braga et al, 2014).…”

New techniques for estimation of source parameters: Applications to airborne gravity and pseudo-gravity gradient tensors

“…The airborne gravity (GT-1A) survey was flown at a constant barometric altitude of 2100 m and a line spacing of 2 km in north-south direction (Ameglio, 2005;Dransfield, 2010). The AGG survey comprised two blocks covering the western and eastern parts of the Vredefort dome area.…”

“…Dransfield (2010) showed that the DNSC08 (global gravity data released by the Danish National Space Center, 2008), ground, airborne gravity (GT-1A) can be used to improve the long wavelength anomalies of the gravity data derived from Falcon AGG data. The conformed vertical component of the gravity vector over the Vredefort dome area gridded with a cell size of 250 m is shown in Figure 5.3.…”

Full-tensor gravity gradient eigenvector analysis for locating complex geological source positions

“…Although Φ z commonly is not directly measured in GGT survey, it can be calculated by using the measured vertical gravity gradient ( Φ zz ) and regional ground gravity data (Dransfield, 2010). …”

“…Pedersen and Rasmussen, 1990;Zhdanov et al, 2004;Fedi, et al, 2005;Dransfield, 2010;Beiki et al, 2011). Various platforms, such as airborne, ground, and satellites have been utilized for GGT data observation.…”