When the DAN-2 (Refs. 1-3) remote spectroradiometer is operated for integral measurement of the content of minor atmospheric gases, it is often needed to use different types of the surface for calibration. This is connected, first of all, with enhancement of DAN-2 capabilities, for example, for indoor operation in extended room, for operation under the cloudy conditions, when calibration to the clear sky becomes impossible, for operation in coal strip mines, under urban conditions, etc. Different types of the surface used for calibration may significantly distort the reference spectrum, and this may lead to ambiguous results. The paper presents the experimental results obtained at DAN-2 calibration from the most characteristic surfaces of the following types: stack, roof, snow, building. These results are compared with the reference calibration signals from the sky. The results obtained are analyzed and interpreted.