The influence of synoptic scale flow on sea breeze induced surface winds and calm zones

High-latitude sea breezes and the related daytime calm zones were studied through fine-scale two-dimensional idealized simulations by varying the direction and speed of the ambient large-scale geostrophic flow in small steps. Strongest coastal afternoon breezes were obtained for moderate large-scale flows 45°–90° left from the pure offshore direction (as seen from the sea), while calm zones appeared near the coast for weak to moderate large-scale flows about 30°–90° right from offshore, and at the seaward edge of the breeze cell for weak ambient flows 45°–90° right from offshore. The complex daytime evolution of the wind field for ambient winds roughly opposing the sea breeze is illustrated via a few key cases.