Aura/MLS observes and SD-WACCM-X simulates the seasonality, quasi-biennial oscillation and El Niño–Southern Oscillation of the migrating diurnal tide driving upper mesospheric CO primarily through vertical advection

[摘要] This work uses 17 years of upper mesospheric carbonmonoxide (CO) and temperature observations by the microwave limb sounder(MLS) on-board the Aura satellite to present and explain the seasonal andinterannual variability of the migrating diurnal tide (DW1) component ofupper mesospheric CO. This work then compares these observations tosimulations by the specified dynamics – whole atmosphere community climatemodel with ionosphere/thermosphere extension (SD-WACCM-X). Results showthat, for all seasons, MLS CO local-time perturbations peaks above85 km andhas a latitude structure resembling the (1,1) mode in temperature. On theother hand, SD-WACCM-X DW1 also peaks above 85 km and has a latitudestructure resembling the (1,1) mode, but it simulates two local maximum of the(1,1) mode between 85 and 92 km. Despite the differences in altitudestructure, a tendency analysis and the adiabatic displacement methodrevealed that, on seasonal and interannual timescales, observed and modeledCO's (1,1) component can be reproduced solely using vertical advection. Itwas also found that both observed and modeled CO's (1,1) component containsinterannual oscillations with periodicities close to that of thequasi-biennial oscillation and the El Niño–Southern Oscillation. From theseresults, this work concludes that on seasonal and interannual timescales,the observed and modeled (1,1) mode affects the global structure of uppermesospheric CO primarily through vertical advection.

[学科分类] 医学（综合）