Model 2: spectra of H₂O v₂ = 1J_Ka,Kc = 5_5,0−6_4,3 at various positions. The black histogram is the observed spectrum at the centre of continuum; the green, blue, cyan, and magenta histograms are the observed spectra along the eastern, southern, western, and northern legs, respectively, at various offset radial distances as indicated in each panel. The red curves are the modelled spectra predicted by ratran.