Impact of sea surface temperature on stratiform cloud formation over the North Sea

Abstract

Abstract This study presents a numerical simulation assessing the effect of dynamical ocean–atmosphere coupling on the structure of the marine atmospheric boundary layer over the southern North Sea. Using a high‐resolution regional coupled ocean‐atmosphere prediction system, with a coupling frequency of 1 h, a diurnal variation of sea surface temperature simulated by the ocean model is applied to the atmosphere component. This results in a surface warming in the coupled compared to an atmosphere‐only run. Shallow convection initiated by heating of the lower atmosphere by a relatively warmer ocean surface leads local formation of low level clouds between 1300 h and 1700 h in the coupled run. The impact of these clouds in reflecting incoming solar radiation is demonstrated through a relative cooling of the sea surface temperature in the coupled simulation compared to an ocean‐only run forced by an atmosphere‐only run without representation of ocean‐atmosphere interactions.