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The ability to predict heavy rain and floods in Africa is urgently needed to reduce the socioeconomic costs of these events and increase resilience as climate changes. Numerical weather prediction in this region is challenging, and attention is being drawn to observationally based methods of providing short-term nowcasts (up to ∼6-h lead time). In this paper a freely available nowcasting package, pySTEPS, is used to assess the potential to provide nowcasts of satellite-derived convective rain rate for West Africa. By analyzing a large number of nowcasts, we demonstrate that a simple approach of “optical flow” can have useful skill at 2-h lead time on a 10-km scale and 4-h lead time at larger scales (200 km). A diurnal variation in nowcast skill is observed, with the worst-performing nowcasts being those that are initialized at 1500 UTC. Comparison with existing nowcasts is presented. Such nowcasts, if implemented operationally, would be expected to have significant benefits. Significance Statement A freely available, easy-to-use nowcasting package has been applied to satellite-retrieved rainfall rates for West Africa, and extrapolations have useful skill at up to 4 h of lead time.

A solution of the multigroup neutron transport equation in one, two, or three space dimensions is presented. The flux ϕg(r, Ω) at point r in direction Ω for energy group g takes the form of an exp...

A solution of the neutron transport equation is obtained by expanding the flux Phi (r Omega ) at position r in direction Omega as a series of the form: Phi (r, Omega )= Sigma l=0N(2l+1) Sigma m=0lPlm(cos theta )( psi lm (r)cos(m phi )+ gamma lm(r)sin(m phi )) where Plm(cos theta ) is the associated Legendre polynomial of order l, m with theta and phi the axial and azimuthal angles, respectively, of Omega . psi lm(r) and gamma lm(r) satisfy first-order differential equations and are determined by eliminating terms with odd l and then using finite-difference or finite-element techniques on the resulting second-order system. Complicated algebra is involved in deriving this latter set of relations and FORTRAN subroutines have been written to calculate the necessary coefficients and specify the relevant differentials.

A method for solving the time-dependent diffusion and transport equation is described in which the flux {Phi}({bold r},t) at position {bold r} and time t takes the approximate form {alpha}(t){psi}({bold r},t), where {alpha}(t) depends solely on time. The treatment includes a heat transfer model, thus enabling temperature and expansion feedback effects to be incorporated into the solution.

The transport equationis considered in toroidal geometry using an expansion of Ψ(r, Ω) in unnormalized spherical harmonics, i.e., with being associated Legendre polynomials. The variable r is the p...

The flux φ(r,Ω) at location r in the direction of unit vector Ω is expanded as a series of the form where Pm l(cosθ) are associated Legendre polynomials of order L, m y with ψlm(r) and γlm(r) the coefficients or moments of the series and θ and φ the axial and azimuthal angles respectively of ω. Second order differential equations for ψlm(r) and γlm(r) result when odd l. terms are eliminated from the basic system obtained by substituting the series in the transport equation and these are solved numerically by finite difference or finite element techniques. N specifies the order of the approximation, denoted by PN. Following a summary of the method the paper describes two recent developments, firstly the treatment of anisotropic scatter, with preliminary results, and secondly an efficient means of dealing with vacuum boundary conditions for arbitrary surfaces.

A comprehensive interdisciplinary clinic was established to provide health care for teenaged mothers less than 16 years old and their infants. Thirty-five mother-infants pairs using this clinic were matched with 70 mother-infant pairs who used "traditional" health care facilities. Significant differences in infant outcomes of immunization status at 6 months (91% versus 46% completed), and weight (97% versus 83% within "normal" range) and maternal outcomes of contraceptive use (91% versus 63%), enrollment in educational programs (86% versus 66%), and repeat pregnancy rate (16% versus 38%) were found between Teen-Tot Clinic participants and the control group. Coordination and consolidation of services for teenaged mothers and their infants appears to favorably influence their short-term outcomes.

Finite element methods for problems of neutron transport have been an academic field of activity for over a decade. Reviews of the state of the art have been given by Williams and Goddard (1) and Lewis (2) and a short history of the finite element method in various fields given by Ackroyd (3).