How much of modern atmospheric radiation and remote sensing is back-traceable to first physical principles?

It is widely recognized that the most fundamental physical theory of light–matter interactions today is quantum electrodynamics (QED). However, very little of QED (if any) is used in modern disciplines of atmospheric radiation and remote sensing. On the other hand, it is often claimed that both disciplines are based on first physical principles. It is, therefore, critically important to delineate the extent to which first physical principles are used in actuality and identify branches of atmospheric radiation and remote sensing that remain partially or completely phenomenological and rely on experience-based heuristic shortcuts. In this talk I will focus on physical phenomena associated with elastic electromagnetic scattering and analyze the actual use of physical theories of progressively reduced generality represented by the sequence QED => classical microscopic electromagnetics => classical macroscopic electrodynamics => frequency-domain classical macroscopic electrodynamics => light-scattering phenomenology. This analysis leads to a troubling but inescapable conclusion that the use of modern physics in present-day atmospheric radiation and remote sensing is quite limited.