Conveners
Stratosphere / mesosphere / thermosphere response and coupling of atmospheric layers: (1 invited talk + 2 contributed talk)
- Miriam Sinnhuber (Institut für Meteorologie und Klimaforschung, Karlsruher Institut für Technologie)
- Pekka Verronen
Stratosphere / mesosphere / thermosphere response and coupling of atmospheric layers: (3 contributed talks)
- Pekka Verronen
- Miriam Sinnhuber (Institut für Meteorologie und Klimaforschung, Karlsruher Institut für Technologie)
Stratosphere / mesosphere / thermosphere response and coupling of atmospheric layers: ( 3 contributed talks )
- Pekka Verronen
- Miriam Sinnhuber (Institut für Meteorologie und Klimaforschung, Karlsruher Institut für Technologie)
Stratosphere / mesosphere / thermosphere response and coupling of atmospheric layers: (1 invited talk + 3 contributed talks)
- Miriam Sinnhuber (Institut für Meteorologie und Klimaforschung, Karlsruher Institut für Technologie)
- Pekka Verronen
The EISCAT incoherent scatter radars in Tromsø, northern Norway, and in Longyearbyen, Svalbard measure key parameters of the ionospheric plasma (electron density, electron and ion temperatures, and plasma bulk velocity) at multiple altitudes along the radar beam. The radars are thus ideal instruments for observing electron density enhancements produced by particle impact ionization....
Solar, auroral, and radiation belt electrons enter the atmosphere at polar regions leading to ionization and affecting its chemistry. Whole-atmosphere chemistry--climate models such as WACCM(-X) or EDITh usually parametrize this ionization based on in-situ satellite particle measurements. Widely used particle data are derived from the POES and GOES satellite measurements which provide in-situ...
Modelling the distribution of odd nitrogen (NOx) in the polar middle and upper atmosphere has proven to be a complex task.
Firstly, its production by energetic electron precipitation is highly variable on hourly time scales. Secondly, there are uncertainties in the measurement-based but simplified electron flux data sets that are currently used in atmosphere and climate models. The altitude...
Cosmic dust particles are produced from the sublimation of comets and by collisions between asteroids. The input rate to the atmosphere is estimated to be 27 +/- 14 tonnes per day globally. Because the particles enter the atmosphere at hypersonic velocities, collisional heating with air molecules causes about 30% of them to melt, leading to vaporization of their metallic constituents. The...
On May 10-11, two CMEs arriving within few hours initiated a geomagnetic storm with a DST of around -400 nT in the main phase. With a Kp of 9 for several hours, the threshold for an “extreme” geomagnetic storm was reached for the first time since the Halloween storm in October/November 2003, and polar lights were clearly visible well into magnetic midlatitudes. Proton fluxes were enhanced for...
In the polar middle and upper atmosphere, Nitric Oxide (NO) is produced in large amounts by both solar EUV and X-ray radiation and energetic particle precipitation (EPP), and its chemical loss is driven by photodissociation. As a results, polar atmospheric NO has a clear seasonal variability and a solar cycle dependency which have been measured by satellite-based instruments. On shorter...
Geomagnetic forcing is considered part of the natural forcing of the climate system, and recommended to be included in chemistry-climate model experiments since CMIP6. The starting point is the formation of NO mainly in the lower thermosphere by energetic electron precipitation from the aurora and radiation belts and EUV radiation. We compare results of NO from five high-top chemistry-climate...
Earth system models with tops in the thermosphere have historically struggled to recreate the large nitric oxide (NO) mixing ratios in the high-latitude winter and spring mesosphere and stratosphere. Possible causes include missing sources of energetic particle precipitation, missing chemistry, and errors in the general circulation of the upper atmosphere. Additionally, transport by...
Solicited talk
Solar variability contributes to climate variability at global and regional scales. It is therefore important to include this forcing alongside other natural and anthropogenic factors to simulate past climate and to account for the potential solar influence on future climate projections. However, many challenges exist particularly around how to capture the full effect of...
We have extended the Linearized ozone scheme LINOZ in the ICON (ICOsahedral Nonhydrostatic)-ART (the extension for Aerosols and Reactive Trace gases) model system to include ozone loss caused by energetic particle precipitation (EPP) and changes in the rate of ozone formation due to the variability of the solar radiation in the ultraviolet wavelength range. This extension allows us to...
In recent years, increasing evidence has pointed that winter-time middle atmospheric ozone changes initiated by energetic particle precipitation (EPP) are linked to regional climate variability at ground-level. The mechanism for this link is, however, still unclear. Proposed explanations focusing on EPP-indirect effect does not explain the timing of the observed ground-level changes, which...
Energetic electron precipitation (EEP) directly impacts the high-latitude thermosphere and mesosphere by forming ozone-depleting NOx and HOx. During winter the EEP-NOy (NOx and its reservoir species such as HNO3 formed by EEP) molecules descend to the stratosphere and establish the indirect effect of EEP. Earlier studies based on models and reanalysis datasets have shown that increased EEP is...
The wavenumber-4 (wave-4) structure in the longitude variation of zonal and meridional winds observed by the Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) instrument onboard the Ionospheric Connection Explorer (ICON) satellite is investigated. The amplitude of the wave-4 pattern in meridional wind displays semi-annual variation with equinoctial maxima. In...
