Single-Column Models (SCMs) require observations to provide suitable initial and boundary conditions. To meet this need, the Atmospheric Radiation Measurement (ARM) program conducts Intensive Observing Periods (IOPs) to provide 3-hourly radiosondes and other observations. However, such high-frequency sonde launches can be expensive. Therefore, the ARM program can only support a couple IOPs each year with each one lasting 2-4 weeks. In order to reduce the need for high-frequency sonde launches and to potentially expand the periods available for SCM simulations, they have conducted a study using the Atmospheric Emitted Radiance Interferometer (AERI) and Geostationary Operational Environmental Satellite (GOES) temperature and moisture retrievals, instead of radiosondes, in the ARM variational analysis system (Zhang and Lin, 1997; Zhang et al., 2000) to derive the large-scale forcing terms for driving SCMs during the March 1999 IOP. They have compared the large-scale forcing and associated SCM simulations for various combinations of data sources used in the variational analysis