SUMMARY A generalized form of the cross-validation criterion is applied to the choice and assessment of prediction using the data-analytic concept of a prescription. The examples used to illustrate the application are drawn from the problem areas of univariate estimation, linear regression and analysis of variance.

https://rss.onlinelibrary.wiley.com/doi/pdf/10.1111/j.2517-6161.1974.tb00994.x

Cross-Validatory Choice and Assessment of Statistical Predictions

Companion papers in this series present (1) the role of equatorial E region postsunset ionosphere, (2) the origin of horizontal plasma shear flow in the postsunset equatorial ionosphere (this paper), (3) the Coloured Bubbles experiments results, and (4) computer simulations of artificial initiation of plasma density depletions (bubbles) in the equatorial ionosphere. Within this paper, equations describing the time evolution of the equatorial ionosphere are developed using flux tube integrated and flux tube weighted quantities which model the chemistry, dynamics, and electrodynamics of the equatorial ionosphere. The resulting two-dimensional set of equations can be used to investigate equatorial electric fields neglecting small-scale phenomena (λ < 1 km). An immediate result derived from the integrated current equations is an equation describing the physics of the shear in the horizontal flow of the equatorial plasma during the evening hours. The profile of the horizontal flow has three important contributing terms relating to the neutral wind dynamo, Hall conduction, and the equatorial electrojet current divergence. Using a one-dimensional model of the velocity shear equation and the integrated ionospheric transport equations, a time history of the development of the shear feature during the postsunset hours is presented. The one-dimensional model results are compared to the velocity shear measurements from the Coloured Bubbles experiments.

Theory for modeling the equatorial evening ionosphere and the origin of the shear in the horizontal plasma flow

Six solutions for tesseral harmonic coefficients of geopotential from satellite determinations compared with gravimetry

Tests and combination of satellite determinations of the gravity field with gravimetry

Satellite resonance with longitude-dependent gravity—III. Inclination changes for close satellites

Ionospheric movements measured by incoherent scatter: A review

Upper-atmosphere rotational speed and its variation with height

The odd zonal harmonics in the Earth's gravitational potential are determined by analysing the changes in the eccentricities of six satellites having orbital inclinations spaced as uniformly as possible between 28° and 96°. The most satisfactory representation of the potential is found to be in terms of four coefficients, and their values are, in the usual notation: 10 6 J 3 = −2.56, 10 6 J 5 = −0.15, 10 6 J 7 = −0.44, 10 6 J 9 = 0.12. The resulting potential is compared with that obtained by other authors. Three and five-coefficient solutions are also presented.

Diana W. Scott

Papers

Upper-atmosphere rotational speed and its variation with height

The Odd Zonal Harmonics in the Earth's Gravitational Potential

Odd zonal harmonics in the geopotential, determined from fourteen well-distributed satellite orbits

Further determinations of upper-atmosphere rotational speed from analysis of satellite orbits

Lifetimes of satellites in large-eccentricity orbits