Research Projects: NICE

Negative Ion Chemistry Effects in mesospheric active heating experiments (NICE)

The Aeronomy Group of the Sodankylä Geophysical Observatory studies the chemistry of the mesosphere and lower thermosphere using the detailed ion-neutral Sodankylä Ion Chemistry model (SIC). Both ground-based and satellite observations are used to validate the theoretical approach. The final aim of our work is to estimate the global role of space weather induced variability of the polar upper atmosphere on both short and long time scales.

In the Mesosphere-Lower Thermosphere, between 50 and 100 km altitudes, energetics, dynamics and composition are coupled in a complicated way. Only little attention is paid to the role of the coupling of the neutral and ionised atmosphere at these altitudes, and even less to the significance of negative ions in this coupling. Within this project we want to quantify the role of the negative ion chemistry in the high-latitude mesosphere by combining optimised RF heating experiments in the ionospheric D region with detailed, coupled modelling of the ion-neutral chemistry.

Due to the attachment rate of electrons to neutrals being dependent on electron temperature, the negative ion population can be artificially modified by powerful HF radio waves. In this project we will model as well as measure the actual heating of electrons, deduce the effect of the varying negative ion content on mesospheric composition, and make experimental verifications of these variations. The wealth of available ground-based instrumentation makes Northern Europe a unique region for undertaking the proposed effort.

Partners in NICE:

• Sodankylä Geophysical Observatory, University of Oulu, Sodankylä, Finland
• Finnish Meteorological Institute, Earth Observation Unit, Helsinki, Finland
• Dept of Communication Systems, Lancaster University, Lancaster, U.K.
• British Antarctic Survey, Cambridge, U.K.
• Dept of Physics, University of Otago, New Zealand
• Space Physics Group, Dept of Physical Sciences, University of Oulu, Oulu, Finland
• EISCAT Scientific Association, Kiruna, Sweden, and EISCAT Tromsø, Norway