Equatorial middle atmospheric chemical composition changes during sudden stratospheric warming events
Item
Title (Dublin Core)
Equatorial middle atmospheric chemical composition changes during sudden stratospheric warming events
Description (Dublin Core)
Chemical composition data obtained from the Microwave Limb Sounder (MLS) and Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instruments onboard EOS-Aura and ENVISAT satellites are used to investigate the variation of ozone (O<sub>3</sub>), water vapor (H<sub>2</sub>O) and methane (CH<sub>4</sub>) volume mixing ratios (VMRs) in the height range 20–60 km over the equatorial region during the sudden stratospheric warmings (SSWs) of 2004, 2009 and 2012, the occurrence of which are identified using the ERA (European Center for Medium Range Weather Forecasting Reanalysis) Interim temperature and zonal wind data sets. It is found that the O<sub>3</sub> VMR shows increment whereas H<sub>2</sub>O VMR shows decrement during the SSW event and the possible reasons for these changes in the VMRs are investigated. In the upper stratosphere, the source of water vapor is oxidation of CH<sub>4</sub> which takes place either by hydroxyl (OH) or by atomic oxygen (O). However, the OH VMR available for the year 2009 SSW event does not show any significant variation. The decrease of zonal mean MLS temperature over the equator during the SSW suggests that the rate of the reaction of ozone production (O + O<sub>2</sub> ⟶ O</sub>3</sub> + M), which increases with decreasing temperature, shifts the O/O<sub>3</sub> ratio towards O<sub>3</sub>, resulting in the decrease of CH<sub>4</sub> oxidation and consequent decrease in water vapor.
Creator (Dublin Core)
Nath, O.
Sridharan, S.
Date (Dublin Core)
2018-08-11
Type (Dublin Core)
Text
Format (Dublin Core)
application/pdf
Identifier (Dublin Core)
10.5194/acpd-15-23969-2015
https://acp.copernicus.org/preprints/acp-2015-516/
Source (Dublin Core)
eISSN: 1680-7324
Language (Dublin Core)
eng
