Transport of mesospheric H₂O during and after the stratospheric sudden warming of January 2010: Observation and simulation

Backward trajectory analysis and the zonal mean water vapor distribution from the Microwave Limb Sounder on the Aura satellite (Aura/MLS) indicate the occurrence of two regimes of circulation from 50° N to the North Pole: (1) regime of enhanced meridional mixing throughout February and (2) regime of an eastward circulation in the USLM region reestablished between early March and the equinox. The polar descent rate determined from MIAWARA-C's 5.2 parts per million volume (ppmv) isopleth is 350 ± 40 m d⁻¹ in the pressure range 0.6 to 0.06 hPa between early February and early March.

For the same time interval the descent rate in the same pressure range was determined using Transformed Eulerian Mean (TEM) wind fields simulated by means of the Whole Atmosphere Community Climate Model with Specified Dynamics (SD-WACCM). The average value of the SD-WACCM TEM vertical wind is 325 m d⁻¹ while the along trajectory vertical displacement is 335 m d⁻¹. The similar descent rates found indicate good agreement between the model and MIAWARA-C's measurements.