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An analysis of Mars and Venus only significant source for the nightside nightside electron density profiles obtained with ionosphere of Mars. The lack of a correlation radio occultation methods shows how the nightside would imply that the precipitation source at Mars ionospheres of both planets vary with solar zenith is quite variable. angle. From previous studies it is known that the dayside peak electron densities at Mars and Venus 200 180 c• 160 ._1 • lq-O 0 Venus sol max ß Venus sol min -•-Mars o ß ß o ß ß ß O % ß 120 -lO0 90 1 O0 110 120 130 1 q-O 150 160 170 180

[1] Nineteen new radio occultations of the ionosphere of Saturn have been obtained since 2006. Sixteen of these occultations were from midlatitude and high latitudes and thus provided important, new information of the ionosphere for these regions. A high degree of variability in the electron densities were observed, but grouping and averaging the observations as low-, middle-, and high-latitude ones clearly showed that the electron densities increase with latitude. The topside scale heights also indicate small increases with latitude, but these changes are small enough so these increases may not be statistically significant.

We present a study of latitudinal variations in Saturn's ionosphere using Cassini Radio Science Subsystem (RSS) measurements and Saturn‐Thermosphere‐Ionosphere‐Model (STIM) simulations. On the basis of Cassini RSS observations, the peak electron density (NMAX) and the total electron content (TEC) both exhibit a clear increase with latitude, with a minimum at Saturn's equator. When compared with these RSS trends, current model simulations overestimate NMAX and TEC at low latitudes and underestimate those parameters at middle and high latitudes. STIM is able to reproduce the RSS values for NMAX and TEC at low latitude when an additional low‐latitude loss process, such as a water influx, is introduced near Saturn's equator. The lack of auroral precipitation processes in the model likely explains some model/data discrepancies at high latitude; however, most of the high‐latitude RSS data are from latitudes outside of Saturn's typical main auroral oval. Using Cassini RSS electron density altitude profiles combined with ion density fractions and neutral background parameters calculated in STIM, we also present estimates of the latitudinal variations of Saturn's Pedersen conductance, ΣP. We find ΣP to be driven by ion densities in Saturn's lower ionosphere and to exhibit a latitudinal trend with a peak at mid‐latitude. Model calculations are able to reproduce low‐latitude conductances when an additional loss process is introduced, as before, but consistently underestimate most of the mid‐ and high‐latitude conductances derived from Cassini observations, perhaps indicating a missing ionization source within the model.