Arctic and Antarctic polar winter NO_x and energetic particle precipitation in 2002–2006

Abstract

[1] We report GOMOS nighttime observations of middle atmosphere NO 2 and O 3 profiles during eight recent polar winters in the Arctic and Antarctic. The NO 2 measurements are used to study the effects of energetic particle precipitation and further downward transport of polar NO x . During seven of the eight observed winters NO x enhancements occur in good correlation with levels of enhanced high-energy particle precipitation and/or geomagnetic activity as indicated by the A p index. We find a nearly linear relationship between the average winter time A p index and upper stratospheric polar winter NO 2 column density in both hemispheres. In the Arctic winter [2005][2006] the NO x enhancement is higher than expected from the geomagnetic conditions, indicating the importance of changing meteorological conditions.

Geomagnetic activity signatures in wintertime stratosphere wind, temperature, and wave response

“…They then used a chemistry general circulation model to simulate surface temperature response to geomagnetic activity variations by realistically varying the A p index to further explore the mechanisms leading to the temperature responses reported earlier by Rozanov et al [2005]. The A p -driven NO x parameterization that they used in their model had previously proved to be realistic and in a good agreement with observations [Baumgaertner et al, 2009], concurring well with earlier observations of the relationship between polar middle atmosphere NO x concentrations and the variation in geomagnetic activity and particle precipitation [Siskind et al, 2000;Randall et al, 2007;Seppälä et al, 2007;Sinnhuber et al, 2011]. Baumgaertner et al [2011] showed the temperature response from 0.01 hPa to 1000 hPa (mesopause to surface) when the model was forced with the A p -controlled EPP-NO x (their Figure 9).…”

“…It is now well known that ionization from particle precipitation during geomagnetic activity provides a direct chemical coupling mechanism from the Sun to the atmosphere via the production of NO x and HO x , constituents which are important to middle atmosphere ozone balance [e.g., Randall et al, 2005;Seppälä et al, 2007;Verronen et al, 2011;Andersson et al, 2012]. Geomagnetic activity driven signatures have been found in various meteorological and climate records [e.g., Lu et al, 2008a;Seppälä et al, 2009;Lockwood et al, 2010], but it has remained unclear which mechanism or mechanisms would be responsible for communicating geomagnetic activity variations to climate variables such as stratospheric and tropospheric temperatures.…”

A radiation hardened digital fluxgate magnetometer for space applications

“…This depletes the radiation belts and has potentially important consequences for the atmosphere and climate change (e.g. Seppälä et al, 2007).…”

Mesosphere-to-stratosphere descent of odd nitrogen in February–March 2009 after sudden stratospheric warming

“…In the recent years, observations have shown that during winter times NO x can be effectively transported downwards inside the polar vortex (Funke et al, 2005(Funke et al, , 2007Hauchecorne et al, 2007;Seppälä et al, 2007;, after NO x is produced by particle precipitation in the mesosphere-lower thermosphere (MLT). Although the satellite observations of NO x often cover altitudes up to middle mesosphere only, the connection to lower thermospheric NO x production has been established using VLF (Very Low-Frequency) radio propagation data in the case of the 2004 descent event (Clilverd et al, 2006).…”