EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Planetary wave-driven enhanced NO descent into the top of the Arctic polar vortex during major and minor sudden stratospheric warmings

V. Lynn Harvey1, Nicholas Pedatella2, Seebany Datta-Barua3, Cora Randall1,4, David Siskind5, Katelynn Greer1, and Larisa Goncharenko6
V. Lynn Harvey et al.
  • 1University of Colorado - Boulder, Laboratory for Atmospheric and Space Physics, Atmospheric Sciences, Boulder, United States of America (
  • 2High Altitude Observatory, National Center for Atmospheric Research, Boulder, Colorado
  • 3Illinois Institute of Technology, Chicago, Illinois
  • 4University of Colorado, Atmospheric and Oceanic Sciences Department, Boulder, Colorado
  • 5Space Science Division, Naval Research Lab, Washington D.C.
  • 6Massachusetts Institute of Technology, Haystack Observatory, Westford, Massachusetts

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 (SSW) events. This work is motivated by the fact that state-of-the-art global climate models severely underestimate EPP-NOx abundances in the polar MLT. It is not clear whether this deficiency is due to a missing NOx source or to inadequate transport processes. 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 planetary waves impact the geographic distribution of NO near the polar winter mesopause in the Whole Atmosphere Community Climate Model with thermosphere-ionosphere eXtension combined with data assimilation using the Data Assimilation Research Testbed (WACCMX+DART). We present planetary wave-driven NO patterns near the polar winter mesopause during 16 case studies from the Arctic winters of 2005/2006 through 2018/2019. During all cases the model is in reasonable agreement with Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) derived zonal winds and Solar Occultation For Ice Experiment (SOFIE) and Atmospheric Chemistry Experiment-Fourier Transform Spectrometer (ACE-FTS) NO measurements. Superposed Epoch Analysis is employed to diagnose typical mesopause planetary wave behavior and vertical transport characteristics during 10 minor and 6 major SSW events. Results show that descent of NO into the top of the polar vortex is enhanced by about a factor of 4 in traveling planetary wave troughs vs. in ridges and that this planetary wave-driven enhanced NO descent occurs during both minor and major SSW events. These results present a new conceptual model of zonally varying, vs. zonally uniform, polar descent in the MLT.

How to cite: Harvey, V. L., Pedatella, N., Datta-Barua, S., Randall, C., Siskind, D., Greer, K., and Goncharenko, L.: Planetary wave-driven enhanced NO descent into the top of the Arctic polar vortex during major and minor sudden stratospheric warmings, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-1136,, 2022.


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