An observational operator and its adjoint has been created that is suitable for use within variational data assimilation using new 6 and 10 GHz passive microwave satellite observations. The new operator will allow soil moisture initialization to be performed using future satellite data sets (e.g., NASA AMSR, DoD WindSat, and the NPOESS CMIS). Five primary control variables are used within the operator, and explicitly includes surface soil moisture as one of the control variables. This operator and its adjoint will be used to perform Land Surface Model data assimilation experiments to better determine important NWP surface characteristics. The operator is being incorporated into a 4DVAR system at CSU/CIRA. Current observational operator results and numerical simulations will be presented.