The daytime trapped lee wave pattern and evolution induced by two small‐scale mountains of different heights

Two large-eddy simulations are carried out to investigate the vertical structure and daytime evolution of trapped lee waves (TLWs) triggered by mountains two heights (500 1500 m, denoted as HM500 HM1500, respectively) based on a typical subtropical winter troposphere, in which steady upper-level jet clear diurnal atmospheric boundary layer (ABL) present. Multimode TLWs co-exist at three altitudes with dominant wavelengths increasing altitude HM500, while single-mode TLW dominates throughout most troposphere HM1500. The wave amplitudes for both experiments increase from midday, reaching peaks afternoon, likely related reduction absorption ABL. Whereas growth wavelength time is mainly limited layers near ABL top HM500; HM1500 stays time. pattern can be largely explained linear theory. In multimode due perturbation source low where high wavenumbers supported, lengthening decreasing Scorer parameter afternoon. large-amplitude enhanced elevated higher mountain smaller affected less continual amplification may caused instability wave-induced momentum deficit upper ABL, further facilitates propagation. Our findings beneficial improving our process-scale understanding constrained evolution, have implications orographic gravity-wave parameterization especially when model resolution approaches around 10 km.