RESUMEN
The bremsstrahlung from high and relativistic energy electron precipitation (HEEP) measured with balloon based instruments provides information on energy spectra and fluence of the precipitating energetic electrons allowing calculations of the atmospheric ionization. HEEP from the outer radiation belt at the subauroral region causes an increase in the ionization rates down to about 20â¯km altitudes. We study the variability in the ionization rate using the balloon observations of secondary bremsstrahlung initiated by HEEP. For the first time the changes of atmospheric ionization rates on an hourly and minute time scale at different altitudes was retrieved from balloon observations. These new highlights are important for atmospheric electricity that is sensitive to the local condition in the atmosphere including the local ionization rate.
RESUMEN
In this paper, we present the first results of the ionospheric potential (IP) calculations with the chemistry-climate model (CCM) SOCOL (Solar Climate Ozone Links). For the study, we exploit a parameterization of the difference in electric potential between Earth's surface and lower boundary of the ionosphere as a function of thunderstorm and electrified cloud properties. The model shows a good enough agreement with the IP obtained by balloon soundings. The simulated UT variation of IP exhibits a maximum at 20â¯Universal time (UT) and minimum at about 2â¯UT which agree with the UT cycle of the lightning activity. The obtained results allow understanding of IP variability pattern at diurnal, seasonal and annual timescales. We also compare our results with the IP simulated with the climate model INMCM4 using similar IP parameterization. The comparison shows a good agreement of UT cycles especially before 12â¯UT. Simulated IP annual cycle reaches its maximum in late spring in both models. However, the comparison also reveals some differences in amplitudes of IP variability on different time scales. The large deviations occur after 12â¯UT for all seasons except summer where the maximum of both results happens before 12â¯UT. The UT cycle of IP simulated with CCM SOCOL is in a better agreement with observations after 12â¯UT in terms of phase with similar timing of maximum values. The calculation of IP using climate models can help to fill up the gaps when the observed IP is not available. The interactive calculation of IP is also a step forward in coupling atmospheric and ionospheric processes.