On the treatment of radiative transfer in the lunar diurnal heat flow

The earlier attempts to explain infrared observations of the temperature variation of the lunar surface in terms of heat flow analysis [Wesselink, 1948; Jaeger, 1953] consisted of the solution of the one-dimensional heat diffusion equation expressible as (1)with the specific heat, density, and thermal conductivity as constants, subject to the boundary condition at the surface imposed by solar insolation (2)in which an infrared emissivity of unity and a constant specific insolation is assumed. The unit step function, used to represent zero insolation between sunset and sunrise, is H(X), and A is the Bond albedo of the moon. The sun is treated as a point source during lunation heating and cooling. The manner of treating the sun's altitude, wt, in the equation implies that the solution is for a lunar point at which the sun passes through the zenith during the course of the given lunation. Jaeger's treatment was an extension of Wesselink's method in that two-layer cases of multiple values ofKρc were considered.