Delayed response of the ionosphere to solar EUV variability (DRIVAR)
DFG JA836/33-1 (2016-2019)
Student Assistant position available
The ionospheric plasma reacts on solar EUV and UV variations in the course of the
solar rotation with a time delay of 1-2 days. This delay is assumed
to be owing to transport processes from the lower ionosphere
to the F region, but only limited modeling has been performed
so far to prove this hypothesis.
Within DRIVAR, the processes responsible for the ionospheric
delay will be investigated through comprehensive data analyses
and modeling. Different kinds of solar proxies as well
as spectral EUV and UV fluxes from satellite observations
will be used and analyzed together with ionospheric
parameters from GPS radio occultations and ionosondes,
and, providing both global and high-resolution coverage,
GPS total electron content maps. In particular, the
ionospheric delay will be analyzed at different time
scales (short-term, solar rotation, seasonal time scale),
and the regional dependence of the delay will be analyzed.
The DRIVAR results will provide more insight
into ionospheric processes in general, and
will be most valuable for ionospheric
applications in forecasting ionospheric
weather, e.g. for the use in GNSS error
analyses and predictions.
Due to the complex character of numerous interacting
processes in the thermosphere and ionosphere numerical
modeling is required to physically understand the basic
processes contributing to the delay. We shall use the
Coupled Thermosphere Ionosphere Plasmasphere
Electrodynamics (CTIPe) model to simulate the delay
and, through sensitivity experiments, investigate
and analyze in detail the processes that lead to
the observed delay.
Example of normalized SDO/EVE integrated EUV fluxes and global mean TEC, additionally filtered in the 25-29 days period range. From Jacobi et al., 2016.
Lagged correlation of EUV index and global ionospheric total electron content. From Jacobi et al., 2015.
DLR - Institute of Communications and Navigation
Publications related to the project:
Jacobi, Ch., N. Jakowski, G. Schmidtke, and T.N. Woods, 2016: Delayed response
of the global total electron content to solar EUV variations, Adv. Radio Sci.,
Jacobi, Ch., C. Unglaub, G. Schmidtke, Schäfer, and N. Jakowski, 2015:
Delayed response of global ionospheric electron content to EUV
variations derived from combined SolACES-SDO/EVE measurements,
Rep. Inst. Meteorol. Univ. Leipzig, 53, 1 - 10.
Jacobi, Ch., C. Unglaub, G. Schmidtke, M. Pfeifer, R. Schäfer, R. Brunner,
T. Woods, und N. Jakowski, 2015: Delayed response of global TEC to
ionization variations seen from combined SolACES-SDO/EVE solar EUV
spectra, Proc. 7. Workshop "Solar Influences on the Magnetosphere, Ionosphere and Atmosphere", 1.-5.6.2015, Sunny Beach, 29-32, ISSN 2367-7570 (pdf).
update 28 June 2017 by Ch. Jacobi