Planetary wave-driven enhanced NO descent into the top of the Arctic polar vortex during major and minor SSWs Journal Article uri icon

Overview

abstract

  • ; The polar vortices play a central role in vertically coupling the; Sun-Earth system by facilitating the descent of reactive odd nitrogen; (NO; x; = NO + NO; 2; ) produced in the; atmosphere by energetic particle precipitation; (EPP-NO; x; ). Downward transport of EPP-NO; x; 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-NO; x; 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; NO; x; at high latitudes until the air descends to lower; altitudes.;

publication date

  • November 1, 2021

has restriction

  • hybrid

Date in CU Experts

  • November 9, 2021 2:42 AM

Full Author List

  • Harvey VL; Datta-Barua S; Pedatella N; Cora R; Siskind D

author count

  • 5

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