Microwave temperature least squares fits for the first 18 Garand atmospheres: 1.5– 2.1 cm⁻¹ (≈ 60 GHz or 5000 μm), S∕N = 100 and Gauss SRF with HWHM Γ = 0.001 cm⁻¹ (R ≈ 2000). Black: true profile; blue: linear least squares reconstruction; red: nonlinear least squares with initial guess damped mean profile (Eq. (10)). Temperature differences ΔT = T_fit − T_true are shown as dotted lines with axis at top. Dashed green: fit with initial guess straight line (Eq. (11)). The title gives the atmosphere’s “name”, the number of iterations, and the squared norm of the radiance residuum. Numbers inside the plots indicate the maximum and mean temperature deviations (top) and corresponding UTLS deviations (bottom).