Seven years' observation of mid-upper tropospheric CH4 from AIRS

As one of the most important greenhouse gases, methane (CH4) plays an important role in global warming and atmospheric chemistry. Space-borne remote sensing has been employed for the measurement of CH4 with large spatial and temporal coverage in recent years. This paper presents this observation from the Atmospheric Infrared Sounder (AIRS) on the EOS/Aqua satellite. As a thermal infrared sounder, AIRS can measure the CH4 profile with the most sensitive region in the mid-upper troposphere. An off-line version of the CH4 retrieval algorithm, similar to the version implemented in NASA/DISC, has been used to derive the CH4 products since 2002 at NOAA/NESDIS/STAR. These NOAA products in a 3 degree *3 degree grid are available upon request. The focus of this presentation is the trend of mid-upper tropospheric CH4 in the past seven years based on AIRS observations. Some comparison with ground-based observation and model simulations, as well as some validation to AIRS CH4 products will also be covered.