Atmospheric trace species

Credit by JAXA

Credit by JAXA

“Atmospheric trace species” is the component which mixing ratio is less than 1%, like O3, CO2, CH4 etc. Despite of their small amount, they affect a lot to temperature and circulation of the atmosphere. It also affects human health in the case of air pollution by NOx etc. We have observed the variation of these species mainly by spectroscopic methods such as FTIR and high-altitude balloon observations.

成層圏突然昇温の解明

Credit by NASA

Credit by NASA

The final target of this research is to find out the potential response of the atmospheric compositions affected by Sudden Stratospheric Warming (SSW) in the upper stratosphere and mesosphere. A SSW is a dramatic middle atmosphere event where the polar vortex of westerly (eastward) winds in the winter hemisphere abruptly (i.e. over the course of a few days) slows down (Minor warming) or even reverses direction (Major warming). During such events, the polar stratosphere exhibits warming of tens of degrees over a few days and polar mesospheric cooling has also been observed during SSWs. Over the past decades, satellite instruments have observed the impact of SSW events on minor constituents like carbon monoxide (CO), ozone (O3), nitrous oxide (N2O) and water vapor (HO2). It is now clear that SSWs are dynamical disturbances affecting the entire middle and upper atmosphere, in addition to perturbing the tropospheric circulation (Kvissel, O.-K., et al., 2011). We investigated the impact of SSW in the stratosphere and lower mesosphere using newly obtained data with SMILES (Superconducting subMillimeter Limb Emission Sounder).