Total attenuation measurements of the Intertropical Convergence Zone by satellite altimeter

The 13.9-GHz radar altimeter operating aboard Skylab detected incidences of intense attenuation during a passage over the Intertropical Convergence Zone (ITCZ). The signal returned to the instrument from the surface was reduced by 4.5 and 6 dB over two distinct meteorological disturbances near 8 deg N, 27.5 deg W. Although it is impossible to deduce the vertical composition of the ITCZ cloud band from these data, the usefulness of the radar altimeter as a meteorological sensor of total atmospheric attenuation is demonstrated.