The meridional componentand [xi] the prime vertical component [eta] of DOV are calculated from the two directions of geoid gradients (Heiskanen & Moritz, 1967), that is
Then derivatives of these quadratic polynomials are made to get, andwhich are substituted for equations (1) and (2) to calculate the prime vertical and meridional components of DOV on crossover point.
From Table 1, it can be seen that theprecisions of prime vertical and meridional components are 1.02" and 0.98" comparing with EGM2008-modelled components, respectively, which indicates that oceanic DOVs of crossover points from altimetry data are reliable.
Figures 2 and 3 show annual variations of meridional and prime vertical components of oceanic DOVs determined by the crossover method, respectively.
Figure 3 shows the annualchangesin prime vertical components.
These are used to evaluate both the radius of curvature in the prime vertical (v as above) and the radius of curvature in the meridian p.
v = a/[square root of (1 - [e.sup.2][sin.sup.2][phi])] - Radius of Curvature in the Prime Vertical.
where [N.sup.(k-1).sub.i]--curvature radius of prime vertical, computed for geodetic latitude [B.sup.(k-1).sub.i].
where [N.sub.i]--curvature radius of prime vertical (5), computed for geodetic latitude [B.sub.i].
20-30 km) and for the simplification of the problem the surface of the ellipsoid may be replaced by the surface of a sphere with the curvature radius R = [square root of M x N], where M and N are the radius of curvature of meridian and radius of the curvature of prime vertical respectively calculated with respect to the geodetic coordinates of point [P.sub.i].
1a, 1b show meridian and
prime vertical components of the deflections of the vertical and Fig.
Turning around to follow the
prime vertical down to the eastern horizon, we pass, in descending order, Auriga with bright Capella, Gemini, and Canis Minor with Procyon.