The contribution to the earthlimb radiance from the non-LTE process of resonant scattering of sunlight in the 1--0 band of HCl has been calculated for tangent altitudes from 20 to 90 km. The results show that this is a significant contribution to the radiance at altitudes as low as 20 km and becomes greater than the LTE contribution above 40 km. The possibility of detecting HCl at altitudes as high as 80 km is discussed. |