Abstract:

In this paper, we investigate the research approaches for estimating the gravity at the point, to which it is difficult for mankind to climb, and for the instrument to be carried, in the mountain area from the observed gravity and height of the nearby observation. The research results are as follows. When the wave length for the topographic load λ≤50km,The crustal strength is strong enough to keep the crust not deformed. Therefore, it is improper to use Airy Heiskanen or Pratt Hayford local compensation model to estimate the gravity. Because the free air gravity anomaly is affected by the topographic undulation, we may use the height of nearby point of known gravity to estimate the gravity. Based on this idea, utilizing four kinds of formulas, we give the gravity of Everest (976970±7)×10 -5 ms -2 , which is beneficial to the research for geoid and orthometric height, according to the view of isostasy, the deviation from result mentioned above approaches 100×10 -5 ms -2 .