Atmospheric radiance structures are induced by local temperature and density fluctuations. The design, development, and use of electro-optical surveillance systems require the knowledge of atmospheric radiance clutter at small spatial scales. A model is developed to study radiance fluctuations observed by an airborne IR sensor. This model uses intermediate results of the Air Force Research Laboratory background radiance code SAMM-2 and synthesizes an image of atmospheric background clutter according to the sensor characteristics. Inputs are a 3-D grid of temperature fluctuations and SAMM-2 transfer functions. We extend this code to calculate atmospheric limb viewing irradiance images for airborne and satellite sensors. We detail the irradiance extension of the clutter calculation code and present some results for satellite and airborne viewing conditions.