Multi‐Scale Physical Modulation of Surface‐Layer Wind Profile and Momentum Flux in the Peripheral Circulation of Super Typhoon Yagi

Abstract This study presents analysis of the nearshore marine atmospheric surface layer during Super Typhoon Yagi using detailed observational data. As the typhoon's peripheral circulation intensified, wind speeds increased across the observed heights (16.4–35.1 m), while the vertical wind profile remained relatively uniform, likely due to the limited vertical observation range and strong turbulent mixing. Turbulence in the near‐surface layer transitioned from being dominated by large‐scale vortices to being governed by more active, smaller‐scale vortices. Scale analysis, including ensemble empirical mode decomposition and spectral analysis, revealed that the characteristic turbulent length scale decreased during the typhoon process, suggesting under extreme nonequilibrium conditions, motions that contributed significantly to vertical flux transport were concentrated toward smaller scales. These multiscale turbulent processes played a crucial role in reshaping the wind profile and regulating vertical energy transport, thus offering new insights into mechanisms governing surface layer dynamics under the peripheral circulation of a typhoon.