Climatology of very high ionospheric electron temperature occurrences as observed by Swarm constellation

After more than seven years in orbit, the ESA Swarm satellites have provided an already large statistics of measurements of several important physical parameters of the ionosphere. In particular, electron density and temperature are measured by pairs of Langmuir Probes, and the quality of such data is now considered good enough for many studies, either science cases or climatological characterisations. Concerning specifically the electron temperature, a rather elusive parameter which is quite difficult to correctly characterize “in situ”, and for which the past literature is not so abundant with respect to other ionospheric physical quantities, the overall distributions observed by Swarm are qualitatively consistent with expectations from theory and past observations. However, a non-negligible amount of high and very high electron temperature values is regularly observed, whose distributions and properties are not trivial. In this study we aim at characterizing such features statistically as a function of latitude, local time, and season.