Impact of the Asian Monsoon Anticyclone on Extratropical Lower Stratospheric Water Vapor Distribution observed during the PHILEAS aircraft campaign

The Asian monsoon anticyclone (AMA) stands as a critical player in regional climatic dynamics, wielding profound influence on atmospheric circulation patterns. Despite its well-documented impact on surface weather systems, an intriguing and less-explored dimension of its influence lies in the extratropical lower stratosphere. Especially, water vapor, a climatically significant component, plays a pivotal role in shaping the Earth's radiative balance and, consequently, its climate. Water vapor in the lower stratosphere acts as a key driver of radiative processes, influencing temperature profiles and atmospheric energy distribution.

This study focus on recent measurements from the recent HALO research aircraft campaign PHILEAS in fall 2023, incorporating data on water vapor, methane, and ozone concentrations in the extratropical lower stratosphere. By combining the observational data with meteorological data from ECWMF, we aim to unravel the intricate interactions between the Asian monsoon anticyclone and the distribution of these key atmospheric constituents. The integration of water vapor, methane as AMA tracer, and ozone measurements as stratospheric tracer allows us to discern the specific contributions of the Asian monsoon anticyclone to the composition and dynamics of the extratropical lower stratosphere and the change of the water vapor distribution over the campaign time frame.