Enhanced sporadic E occurrence rates during the Geminid meteor showers 2006–2010

Abstract. Northern Hemisphere midlatitude sporadic E (E_s) layer occurrence rates derived from FORMOSAT-3/COSMIC GPS radio occultation (RO) measurements during the Geminid meteor showers 2006–2010 are compared with meteor rates obtained with the Collm (51.3° N, 13.0° E) VHF meteor radar. In most years, E_s rates increase after the shower, with a short delay of few days. This indicates a possible link between meteor influx and the production of metallic ions that may form E_s. There is an indication that the increase propagates downward, probably partly caused by tidal wind shear. However, the correlation between E_s rates and meteor flux varies from year to year. A strong correlation is found especially in 2009, while in 2010 E_s rates even decrease during the shower. This indicates that additional processes significantly influence E_s occurrence also during meteor showers. A possible effect of the semidiurnal tide is found. During years with weaker tidal wind shear, the correlation between E_s and meteor rates is even weaker.