Coupling of solar and geomagnetic activity with the spatial distribution of trends in green-house gases in the upper atmosphere

• Applicant: Dr. Paul Hartogh
• Subject Area: Atmospheric Science
• Term: from 2015 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 273515838

The structure and composition of the thermosphere-ionosphere (T-I) region is known to be strongly influenced by the EUV flux emanating from the Sun. The other external driver of variability of this region is the Earth's magnetic field which directs charged particles into the atmosphere where they deposit their energy (spatially around poles). Nevertheless, recent data show that several internal driving processes can dominated the T-I variability on very short (days), but also longer time scales (years). A major role in long term forcing is thought to be played by the steady increase of CO2 in the mesosphere and lower thermosphere (MLT), which leads to increasing radiative cooling and subsequent atmospheric contraction. Nevertheless other green-house gases were also found to strongly modulate T-I variability, such as ozone, and NO (on shorter term). Our main goal in this work is to investigate how the spatial distribution of long-term trends of MLT green-house gases couples with T-I long term variability. To this end we plan to use both, ground-based as well as satellite data of CO2, O3, NO, H2O, neutral and electron densities. Combining the data from the following space experiments: CHAMP, GRACE, SWARM, COSMIC, GOMOS, ACE-FTS, MLS, SABER, MIPAS, HALOE, and AIM we plan to obtain nearly a global coverage over a period of nearly 2 solar cycles. The global climatologies will be build using these datasets and derive the long term trend and their correlations in time and space and with T-I indices. We will investigate the possible time lags in variability and constrain what dynamical and chemical pathways may be responsible in driving the T-I response to these changes. In addition, we plan for the first time to calculate true cooling/heating rates from the global climatologies and investigate how these and T-I regions correlate. These can also later be used directly in the global circulation models, as oppose to the energetics cooling rates derived from measured volume emission rates.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1788: Study of Earth system dynamics with a constellation of potential field missions
• Co-Investigator: Dr. Ladislav Rezac
• Cooperation Partner: Dr. Alexander Medvedev