East Asian Monsoon and Tropospheric Ozone from IASI/MetOp

Abstract : As an important greenhouse gas and air pollutant in the troposphere, monitoring of tropospheric ozone (O3) is essential to understand its impact on air quality, chemical composition and climate. In this presentation, two independent studies using O3 measurements from the Infrared atmospheric Sounding Interferometer (IASI) are presented. First, sensitivity studies are performed to investigate the origin of the systematic IASI O3 positive bias with respect to independent observations, which is reported in the literature. Second, the East Asian monsoon variability is assessed using six years of IASI tropospheric O3 columns. The study shows the ability of the instrument to detect the effect of the monsoon on the tropospheric ozone column and to reproduce the strength of the monsoon from one year to the other. Focusing on the period of May-August 2011, the WRF-Chem model is used at the surface and in the troposphere in conjunction with IASI to assess the meteorological and dynamical effects during the monsoon period on the tropospheric ozone column.