Statistical studies of jovian decameter emissions observed during the sameperiod by Nancay Decameter Array (France) and WAVES experiment aboard Windspacecraft

Occurrence probabilities and polarization characteristics of the decameter jovian emissions (DAM) have been analysed by combined ground and space obse rvations. We use the data observed in the same period by the Nancay decamet er array (France) and the WAVES experiment on board Wind spacecraft. The gr ound observations cover the frequency range 10 to 40 MHz when the space exp eriment records the lower part of the spectrum from 1 MHz up to 13.8 MHz. D ifferent observation conditions lead to a better description of the jovian decameter emissions where the ground-based and space observations are perfo rmed with distinct type of antenna and complementary receivers. The combination of Nancay decameter observations and the WAVES/Wind data al low to analyse in terms of occurrence probability and polarization more tha n 200 events. After midnight and between 02:00 UT and 04:30 UT, 50% of thes e events are simultaneously observed from the ground and in space. In the I o-phase CML diagram, the ground observations are mainly related to Io-A and Io-B sources with right-hand polarizations and Io-C and Io-D sources with left-hand polarizations. For WAVES/Wind observations, the occurrences are r elated to Io-controlled (Io-C and Io-D) and non-Io-controlled emissions whe re we note the quasi-absence of,Io-A and Io-B sources. The main differences in the occurrence probability between ground and space observations are in terpreted as an effect of Earth ionosphere and receiver frequency coverages .