Impacts of large-scale circulation on convection are investigated by carrying out several sensitivity tests with a two-dimensional cloud resolving model. The model has a 20480-km domain and a cyclic lateral boundary. The sea surface temperature (SST) is not uniform over the model domain. The warm region with the uniform SST of 29.5 C and the cold region with the uniform SST of 26 C are separated by the regions with SST gradients. SST is symmetric about the centers of the warm and cold regions. The SST gradient forces large-scale circulations with the upward motion in the warm region and the downward motion in the cold region. The SST gradient and sizes of the warm and cold regions are the two parameters that determine intensity and structure of large-scale circulation. In the control experiment, the sizes of warm and cold regions are equal. Experiments with different sizes of the warm and cold regions and with different SST gradients and with the uniform SST are compared with the control experiment to reveal the impacts of large-scale circulations on convection. Further, the cloud resolving model couples with an ocean mixed-layer model to investigate the feedback of ocean on the atmospheric convection. The cloud organization and propagation, vertical structures of temperature and moisture and cloud contents, and their diurnal variations will be analyzed. The heat and water budgets in the warm and cold regions and the regions with SST gradients will be calculated. The results will be presented at the meeting