The Analytical and Quick Computation Method of Disturbing Gravity in Global and Local Ocean Area

• Main Authors: ZHAI Zhenhe, SUN Zhongmiao, WANG Xingtao
• Format: Article
• Language: zho
• Published: Surveying and Mapping Press 2015-08-01
• Series: Acta Geodaetica et Cartographica Sinica
• Subjects: geodesy; disturbing gravity; geoid; vertical deflection; quick algorithm
• Online Access: http://html.rhhz.net/CHXB/html/2015-8-827.htm

In order to solve the problem of deriving the disturbing gravity from satellite altimetry data, the analytical formula of disturbing gravity computed from geoid and vertical deflection are derived. The analytical formula can be used to get global ocean disturbing gravity by using altimetry data. Considering the existing achievements, the two improved quick computation methods which are respectively according to the global and local area are also get based on the one dimensional FFT algorithm. The quick computation methods can get the same results as the analytical computation and improve the computation speed of 20 times. The precise, quick computation methods can avoid the problem of aliasing and edge effects and have the flexible application. The 2.5' resolution of geoid and vertical deflection derived from EGM2008 model are used to compute the global and local ocean disturbing gravity. The results show that the difference between two method is about 0.8×10^-5 m/s², so the disturbing gravity respectively derived from geoid and vertical deflection are consistent. Considering the actual situation, the disturbing gravity derived from vertical deflection still has some advantages.