Speaker
Description
We introduce the Palau Atmospheric Observatory as an ideal site to detect changes in atmospheric composition and dynamics above the tropical West Pacific, the main global entry point for air masses into the stratosphere in boreal winter. The comprehensive set-up of the site consists of an aerosol and cloud lidar, a sun photometer, a Fourier Transform Infrared Spectrometer and a ground station for balloon soundings with radio-, ozone-, water vapor- and aerosol-sondes. We focus on the ozone sounding program from 2016-2023, which includes our participation in two major aircraft campaigns (POSIDON, ACCLIP). The year-round high convective activity is reflected in dominant low tropospheric ozone and high relative humidity. According to our analysis, the origin of anomalous ozone-rich and dry air masses is the Tropical Asian troposphere. The seasonal distribution of both constituents and thus air mass origin is unique compared to other sites and modulated by the Intertropical Convergence Zone.
