With the advent of the first commercial solar power tower plants with a rated power in the 10-20 MW range, scale-up to larger 20-50 MW commercial plants is being considered (Lata et al., 2010; Herring, 2009) in the vast arid regions of the sunbelt. In the case of single-tower plants, the heliostat field size grows considerably and the heliostat receiver slant range distances are often over 1 km. Solar radiation attenuation over these distances cannot be neglected and must be taken into consideration during plant design. The measurement of the atmospheric attenuation is not an easy task and the use of spectral atmospheric transmission models is necessary. We used the MODTRAN (MODerate resolution atmospheric TRANsmission) code to study the solar radiation attenuation at different slant range distances in different scenarios: rural atmosphere on a clear day (visibility 23 km) and rural atmosphere on a hazy day (visibility 5 km). (C) 2011 Elsevier Ltd. All rights reserved.