A model of correlating atmospheric cross flow and the fluid flow inside a solar updraft tower (SUT) was presented by assuming SUT inflow as a compressible flow. The influence of atmospheric cross flow on SUT inflow was studied using the model. Results showed that atmospheric cross flow had a large influence on SUT inflow, and the SUT inlet air velocity approximately equaled to 26% of cross flow velocity for collector air temperature rise Delta T = 0 degrees C. With an increase in atmospheric cross flow velocity, the fluid flow velocity inside SUT was found to increase. The enlargement effect of pressure potential and SUT inlet air velocity induced by atmospheric cross flow increased with higher SUT height, but decreased with higher temperature rise, which is proportional to collector area. The percentage enlargement for cross flow to the pressure potential was between 67% and 102% and that to the SUT inlet air velocity was between 33% and 48%, for H varying from 100 m to 3000 m and Delta T = 20 degrees C. The enlargement drastically decreased for Delta T varying from 0 degrees C to 80 degrees C for H = 900 m. The work would lay a good foundation for accurate predication of potential power production from SUT power plants by considering the effect of atmospheric cross flow. (C) 2012 Elsevier Ltd. All rights reserved.