The general characteristics and microwave radiative properties of sea ice in the Weddell Sea region during the onset of spring are studied by using the NIMBUS 7 Scanning Multichannel Microwave Radiometer (SMMR) and other satellites sensors in conjunction with in situ observations from the Mikhail Somov. The position of the ice edge, the gradient of ice concentration, and the width of the Marginal Ice Zone are inferred from the microwave data and are found to be consistent with ship observations especially at 18 GHz. The sensitivities of the various SMMR features to surface and other effects are investigated by using multi-spectral cluster analysis. The results show condierably variability in emissivity, especailly at 37 GHz, likely associated with varying degrees of surface wetness. Ice concentrations are derived by using two methods: one that assumes fixed emissivities are consolidated ice and an iterative procedure that accounts for the various emissivities observated. By using the procedure tha allows the amissivities to be various gives ice concentrations that are more consistent with qualitative field observations.