The Changing Polar Ionosphere: A Comparative Climatology of Solar Cycles 23 and 24

Lead Research Organisation: University of Leicester
Department Name: Physics and Astronomy


The polar ionosphere has a range of effects on technological systems produced by the coupling of the solar wind with the magnetosphere, and the resulting electrodynamic interaction between magnetosphere, ionosphere and atmosphere. These effects include the degradation of trans-ionospheric satellite communications and point-to-point radio communications, clutter effects in over-the-horizon radars, and increased levels (and decreased predictability) of satellite drag.

Such effects are known to be strongly influenced by the activity level of the sun, and hence the phase of the 11-year solar activity cycle. Recent changes in solar activity have taken the scientific community by surprise, in that the recent solar minimum was both extended in time, and much lower in activity than predicted. As we now approach solar maximum we see an increasing solar activity, but this rise in activity is also less than expected.

We propose an extensive statistical investigation of the profound changes imposed on a number of fundamental ionospheric characteristics by the changing solar cycle, focussing on the inter-cycle differences between solar cycle 23, a "standard" solar cycle, and the most recent, unusual solar cycle 24.

Furthermore, we will extend this analysis of solar cycle dependence and inter-cycle differences to a number of ionospheric and atmospheric characteristics which have a direct effect on the operational characteristics of key technologies such as trans-ionospheric communication, satellite navigation and radar systems.

This major step forward in defining and understanding these effects and their dependence on the level of solar activity will allow a prediction of their consequences for the polar ionosphere and atmosphere, and for the technological systems we operate in the polar regions.

Planned Impact

The impact of the proposed research will be focussed on the following groups:

HF users. The ionospheric density at high latitudes plays a critical role in the availability of HF communication paths, as used by both civil aviation and the military. Maps of ionospheric morphology as a function of season, solar cycle phase, and the analysis of inter-cycle differences will form important new inputs for users in these areas.

GNSS users. Maps of seasonal, solar cycle, and inter-cycle variations in ionospheric irregularity occurrence will be of direct applicability to the assessment of space weather effects on GPS navigational systems.

Over-the-Horizon radar (OTHR) users. Irregularity occurrence is a major contribution to radar clutter in OTHR systems. The location and intensity of such structures will provide a highly valuable input to enhance our understanding of the operational impact of ionospheric perturbations.

Space infrastructure operators. Thermospheric heating causes the Earth's atmosphere to expand, increasing the atmospheric drag on satellites in low Earth orbits. This increases the risk of spacecraft collisions and results in large uncertainties in the re-entry location of de-orbiting spacecraft.

The ionospheric modelling community. The ionospheric changes dependent on long time-scale variations in solar activity; the effect of inter-cycle variation on future ionospheric structure, and the statistical analysis of ionospheric convection morphology will be of direct applicability as input to the current efforts of the UK global ionospheric modelling community.

Society. The pursuit of scientific discovery and knowledge is a cultural endeavour which enriches society through its power to inspire and educate, and directly contributes to the wider knowledge-based economy.

We will define and disseminate our research results through peer-reviewed publications, through presentations at meetings such as the annual European Space Weather Week, and through the two workshops planned as part of the research programme.

Our outreach activities will continue to be delivered through public events involving, for example, the Planeterela and the National Space Centre.


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Blagoveshchenskaya N (2014) Optical and ionospheric phenomena at EISCAT under continuous X -mode HF pumping in Journal of Geophysical Research: Space Physics

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Blagoveshchenskaya N (2017) First observations of electron gyro-harmonic effects under X-mode HF pumping the high latitude ionospheric F-region in Journal of Atmospheric and Solar-Terrestrial Physics

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Burrell A (2019) AMPERE Polar Cap Boundaries

Description We have quantified some significant differences between the high latitude ionospheric state for the most recent deep solar minimum and the previous solar minimum. This has included significant alterations to the HF propagation environment and unexpected differences in the characteristics of the ionospheric convection

In order to achieve this we have developed and published algorithms for significant improvements in data analysis with SuperDARN radars.

We have produced calibration data for the Hankasalmi radar interferometer
Exploitation Route The radar analysis improvements will be of great interest to the SuperDARN community in future studies.
The radar calibration effort is already being applied to SuperDARN analysis, and its exploitation forms a part of a current grant application.
Some open questions have been raised by the research which will form the basis of future research.
Sectors Aerospace, Defence and Marine,Digital/Communication/Information Technologies (including Software),Environment

Description Super Dual Auroral Radar Network 
Organisation Johns Hopkins University
Department Applied Physics Laboratory (APL)
Country United States 
Sector Charity/Non Profit 
PI Contribution The continued operations of the two CUTLASS radars enabled the RSPP group to maintain its collaborations within the Super Dual Auroral radar Network. This network involves institutes from Australia, Canada, China, Finland, Italy, Japan, Sweden, South Africa, United Kingdom and United States of America. Note that there is insufficient time to go into detail for all of the releveant collaborations involved in this project.
Collaborator Contribution Through contributions of radar data plus effort on software development.
Impact Publications Funding to build new radars for groups in China and Japan Start of contract to build a new radar for group in Russia
Start Year 2006
Description ePOP-SuperDARN 
Organisation University of Calgary
Department Department of Physics and Astronomy
Country Canada 
Sector Academic/University 
PI Contribution Analysed data and implemented special operational modes to validate and supplement satellite observations.
Collaborator Contribution Provided observations that motivated the development of improved radar location techniques.
Impact 10.1002/2015RS005808
Start Year 2015
Title davitpy.pydarn.proc.fov 
Description Developed and distributed software to automatically determine the origin direction and propagation mode of HF radar backscatter. 
Type Of Technology Software 
Year Produced 2015 
Open Source License? Yes  
Impact Greatly reduces error in determining origin location of radar observations.