The General Circulation Model (GCM) of the Goddard Laboratory for Atmospheric Sciences (GLAS) was integrated for 107 days starting from the initial conditions of 15 May. In this experiment the clouds dynamically generated by the model affect the radiative heating fields continuously. Starting from the initial conditions valid for day 76 of this run, another integration was made for 31 days in which the clouds were specified on certain grid points, remaining fixed during the period of integration. The spatial distribution of the fixed clouds was such that the aggregate cloud frequency for a vertical level and each latitude circle remained the same as in each control run, and the highest cloud frequency grid points were assigned the cloudiness of 100%. The 31-day mean simulation of the second run (fixed clouds) is compared with the last 31-day mean simulation of the first run to study the effects of cloud-radiation feed- back on the mean monthly circulation, atmospheric energy cycle and the hydrolo... Abstract The General Circulation Model (GCM) of the Goddard Laboratory for Atmospheric Sciences (GLAS) was integrated for 107 days starting from the initial conditions of 15 May. In this experiment the clouds dynamically generated by the model affect the radiative heating fields continuously. Starting from the initial conditions valid for day 76 of this run, another integration was made for 31 days in which the clouds were specified on certain grid points, remaining fixed during the period of integration. The spatial distribution of the fixed clouds was such that the aggregate cloud frequency for a vertical level and each latitude circle remained the same as in each control run, and the highest cloud frequency grid points were assigned the cloudiness of 100%. The 31-day mean simulation of the second run (fixed clouds) is compared with the last 31-day mean simulation of the first run to study the effects of cloud-radiation feed- back on the mean monthly circulation, atmospheric energy cycle and the hydrolo...