[A-CG33] Multi-scale ocean-atmosphere interaction in the tropics

[ACG33-P07] The response of atmospheric boundary layer height to El Niño/La Niña events

*Chen-Jeih Pan¹, Shih-Sian Yang¹ (1.Department of Space Science and Engineering, National Central University)

Keywords:atmospheric boundary layer, El Niño and La Niña, ERA5 reanalysis data

The height of the atmospheric boundary layer (ABLH) is a critical parameter for weather and climate that affects the energy exchange, hydrological processes, and pollutants diffusion in the lower atmosphere. The climatology of ABLH has been studied in numerous papers. However, the response of ABLH to El Niño/La Niña events is absent in the literature. The present study employed the ABLH retrieved from ERA5 reanalysis data to investigate the variations of ABLH caused by El Niño/La Niña events. The investigation shows a significant change in ABLH over the equatorial Pacific Ocean, with a peak-to-peak magnitude of about 30% of the long-term mean ABLH between El Niño and La Niña conditions. This change in ABLH can be associated with the migration of the intertropical convergence zone (ITCZ) and South Pacific convergence zone (SPCZ) because of low ABLH over these convergence zones. The effects of El Niño/La Niña events further modify the ABLH over the globe through migrations of synoptic-scale weather systems. The results of this study suggest that the influence of El Niño/La Niña events on ABLH shall be considered for the applications of boundary layer meteorology.