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China’s Mars exploration mission has stimulated tremendous interest in planetary science exploration recently. To propose potential scientific research projects, this study presents a concept simulation for the measurement of Martian atmospheric winds using the Doppler Michelson interferometry technique. The simulation is based on the satellite instrument initially designed for the Dynamic Atmosphere Mars Observer (DYNAMO) project to measure vertical profiles of winds from the 1.27 μm airglow observations in the Martian atmosphere. A comprehensive DYNAMO measurement simulation forward model based on an orbit submodel, an atmospheric background field submodel, and an instrument submodel is developed using the Michelson equation. The simulated interferogram signal over the field of view (FOV) calculated by the forward model is associated with the filter transmittance function, column emission rate of airglow, wind velocity, temperature, and the Michelson phase. The agreement between the derived atmospheric signals from the simulated interferogram without altitude inversion and the input parameters used to initiate the forward model confirms the validity of the forward model.

With an improved method for retrieving the equatorial Fregion irregularities (EFIs) from radio occultation measurements, a huge amount of S4 index profiles from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites is employed to study the solar cycle variation of global EFIs during the period of 2007 to 2017. This full solar cycle data show that impacts of the solar activity on the occurrence rates and heights of EFIs are notable and complex. The occurrence rates of EFIs at higher altitude (greater than 500 km) increase with increasing the solar activity. The mean heights ( h~) and heights standard deviation (σh) of EFIs at higher altitudes do not show clearly the solar activity dependence. On the other hand, the occurrence rates of EFIs at entire altitudes (from 150 to 800 km) do not have clear relation with the solar activity. The h~and σhof EFIs at entire altitudes increase with increasing the solar activity. Moreover, the dependence of the occurrence rates of EFIs on the solar activity are the strongest in the equinoxes, weaker in winter and weakest in summer. The electric fields and corresponding seasonal variation can account for the EFIs occurrence and height variation versus solar activities, and the EFIs at low altitudes seem to be related to the seedassociated with atmospheric gravity wave. The performance of EFIs changes with solar activity is complex. The solar dependence of EFIs seems to be inconsistent when using different observation, i.e. the ground‐base observation indicates no solar dependence, but space‐based observation indicates very good solar dependence. We suppose that this may be due to the fact that EFI at different altitudes is has different solar dependence. For the first time in this article, we have distinguished the information of the height of the EFIs. This is the great advantage of the COSMIC occultation data. After distinguishing the heights, it was found that the occurrence of EFIs above 500 km was well correlated with solar activity, and the correlation between the entire height of EFIs and solar activity was weak. The results of this study are a good explanation of the reasons for the inconsistency of the previous researcher's EFIs solar dependence study. We use COSMIC occultation data statistical studies on climatological characteristics of the global EIFsThe occurrence of EFIs above 500 km was well correlated with solar activityThe correlation between the entire height of EFIs and solar activity was weak

In this paper we presented two typical global 6-day planetary wave oscillations occurring in sporadic Elayers. By analyzing the foEstime series observed from several ionosonde stations on the basis of the methods suggested by Haldoupis and Pancheva (2002), we computed estimates for the PW propagation direction, zonal wave number and phase velocity. We obtained results that the 6-day PW, with zonal wave number about 1, propagates westward, which are in agreement with those reported from radar and satellite neutral wind MLT measurements. The results provide experimental evidence for a close relationship between PWs and midlatitude Es. In addition, the study proves the validity of Esobservations measured routinely and rather reliably with a dense global network of digital ionosondes used as an alternative means of studying large-scale neutral atmospheric dynamics in the MLT region.

Quasi 6-day oscillations in Esoccurrence were observed to occur in relation with planetary wave activity at Wuhan, China (30.6°N, 114.5°E). Wavelet analysis of Esoccurrence time series revealed that a strong 5- to 7-day oscillation was present during the period from about day 120 to 137 of 2003. The same quasi 6-day planetary wave oscillation was also found to dominate the spectrum of concurrent wind data measured in the 80- to 100-km region by a meteor radar, in agreement with the Esoccurrence. There is also a great deal of similarity between the 5- to 7-day band-pass filtered waveforms of Esoccurrence and the wind data. By estimating the wave phase changes with altitude, the quasi 6-day PW in the zonal wind was found to be in phase with the sporadic Elayer critical frequency, foEs, at about 115 km, close to the observed Esheight. The quasi 6-day PW modulation was also present in the amplitude of the 12-h and 24-h periodicities which existed in the foEstime series. The present results provide new evidence in favor of a planetary wave indirect role on Esformation through the modulation of tides, which in line with previous studies by Haldoupis and Pancheva (2002), and Pancheva et al.(2003).

Sudden stratospheric warming (SSW) events in Northern Hemisphere winter atmosphere play a significant effect on large ionospheric disturbances. Nevertheless, the SSW effects on small‐scale structure in ionosphere, that is, the ionospheric Flayer irregularities, are generally lack of understanding. This work carefully studied the equatorial Flayer scintillation during the SSW event extending from 4 January to 5 February in 2013 by using the data of COSMIC/FORMOSAT‐3 (a Constellation Observing System for Meteorology, Ionosphere, and Climate mission). The occurrence rate of ionospheric Flayer scintillation was found to be apparently decreased by about 30% during the SSW period. This phenomenon was obviously seen in American sector (90°W–0°) and African sector (0°–90°E). Another prominent feature was the ~0.5 local time hour delay of maximum scintillation occurrence rate associated with the suppression of equatorial Flayer irregularities in the first 2 hr after the sunset during the SSW event in January 2013. It is the first time to study the response of small scale structure in ionosphere during SSW by COSMIC data setsThe occurrence rate of ionospheric F‐layer scintillation weakened by about 30% during the January 2013 SSW eventThe weakening is obvious in American and African sectors, not obvious in other sectors, which are attributed to low scintillation in winter