Measurements from the Solar Occultation For Ice Experiment (SOFIE) are used to characterize meteoric smoke and meteor influx in both hemispheres. New smoke extinction retrievals from sunrise measurements in the Northern Hemisphere (NH) are presented, which complement the previously reported sunset observations in the Southern Hemisphere (SH). The sunrise observations are in good agreement with simulations from the Whole Atmosphere Community Climate Model (WACCM), for both the seasonal and height dependence of smoke in the mesosphere. The SOFIE - WACCM comparisons assumed that smoke in the mesosphere exists purely as Fe-rich olivine. This is justified because olivine is detected optically by SOFIE, it has the same elemental abundance as incoming meteoroids, and it is anticipated by theory and laboratory experiments. Treating mesospheric smoke as olivine furthermore brings closure in terms of the ablated and total meteoric influx determined here from SOFIE and a recent and independent investigation based on models and observations. SOFIE observations from 2007 - 2021 indicate a global ablated meteoric influx of 7.3 +/- 2.0 metric tons per day (t/d), which corresponds to a total influx (ablated plus surviving material) of 25.0 +/- 7.0 t/d. Finally, SOFIE indicates less smoke in the polar winter SH compared to NH winter. Finally, the results indicate stronger descent in the NH polar winter mesosphere than in the SH winter. This hemispheric asymmetry is indicated by smoke and water vapor results from both SOFIE and WACCM.

The polar vortices play a central role in vertically coupling the Sun-Earth system by facilitating the descent of reactive odd nitrogen (NOx = NO + NO2) produced in the atmosphere by energetic particle precipitation (EPP-NOx). Downward transport of EPP-NOx from the mesosphere-lower thermosphere (MLT) to the stratosphere inside the winter polar vortex is particularly impactful in the wake of prolonged sudden stratospheric warming events. This work is motivated by the fact that state-of-the-art global climate models severely underestimate this EPP-NOx transport in the Arctic. As a step toward understanding the transport pathways by which MLT air enters the top of the polar vortex, we explore the extent to which Lagrangian Coherent Structures (LCS) impact the geographic distribution of NO near the polar winter mesopause in the Whole Atmosphere Community Climate Model eXtended version with Data Assimilation Research Testbed (WACCMX+DART). We present planetary wave-driven enhanced NO descent near the polar winter mesopause during 14 case studies from the Arctic winters of 2005/2006 through 2018/2019. During all cases the model is in reasonable agreement with SABER temperatures and SOFIE and ACE-FTS NO. Results show consistent LCS formation at the top of the polar vortex during minor and major SSWs. LCSs act to confine air with elevated NO to high latitudes as it descends into the top of the polar vortex. Descent of NO tends to be enhanced in traveling planetary wave troughs. These results present a new conceptual model of transport in the polar winter mesosphere whereby regional-scale, long-lived LCSs, coincident with the troughs of planetary waves, act to sequester elevated NOx at high latitudes until the air descends to lower altitudes.