## 5 Conclusions  
In this study, we have analyzed and presented the multi-instrumental observations of midlatitude plasma irregularities over Eastern Asia that occurred during a moderate magnetic storm on 16 July 2003. Through a global view of GNSS ROTI, we found that ionospheric F-region irregularities were observed from the equator to middle latitudes over Eastern Asia at 18 UT on 16 July 2003. It is further found that midlatitude SSF, lasting for several hours, mainly occurred in the midnight-morning sector over Japan during this storm. During the recovery phase of this storm, DDEF induced by the thermospheric disturbance winds and PPEF caused by the over-shielding electric field work together to be responsible for the enhanced eastward electric field and hence cause the uplift and latitudinal extension of EPBs to further generate the observed SSF and the enhancement of ROTI at midlatitudes. On the other hand, plasma density increased significantly during this storm compared with that on the reference day, because the plasma was transported from the equatorial region to higher latitudes. In addition to SSF observed during this storm, other common type of spread F, FSF, was observed in the Japanese sector on the reference day and/or at high latitude station WK545, which seems to be closely related to the coupling of MSTIDs and the Es layer. The above results indicate that various types of midlatitude spread F can be generated by different physical processes, showing the complicated day-to-day variability of the occurrence and characteristics of ionospheric F-region irregularities at midlatitudes. Significantly, we note that only midlatitude SSF related to the extension of EPBs, identified as clear plasma depletions by the satellites during this storm, can obviously affect the performance of the GNSS receiver as shown in Figure 1. More cases and numerical simulations are needed for further investigation and confirmation. Overall, the above results emphasize the effects of magnetic storm on the generation and evolution of midlatitude plasma irregularities. It is suggested that more research and attention should be given to midlatitude plasma irregularities in future studies. Conceptualization, H.Y., W.Y., J.W. ([PERSON]) and X.X. ; methodology, H.Y. and X.X. ; software, B.Z. ; validation, J.W. ([PERSON]) and C.L. ; investigation, B.Y. and X.X. ; data curation, P.T., C.L. and M.L. ; writing--original draft preparation, H.Y. ; writing--review and editing, W.Y., [PERSON] ([PERSON]), B.Y. and X.X. ; visualization, H.Y. and B.Z. ; supervision, X.X. ; project administration, T.C. ; funding acquisition, X.X. and X.D. All authors have read and agreed to the published version of the manuscript. Figure 11: Detrended total electron content (TEC) maps over Japan ([[https://aer-nc-web.nict.go.jp/GPS/GEONET/](https://aer-nc-web.nict.go.jp/GPS/GEONET/)]([https://aer-nc-web.nict.go.jp/GPS/GEONET/](https://aer-nc-web.nict.go.jp/GPS/GEONET/)) (accessed on 20 January 2023)) from 13 to 15 UT on 15 July 2003. The detrended TEC maps are obtained using a 15 min running window. **Funding:** This work was supported by the National Key R\(\backslash\)&D Program of China (Grant No. 2022 YFP0503703), the National Natural Science Foundation of China (42188101, 42125402, 42074181, 42174183), the Project of Stable Support for Youth Team in Basic Research Field, CAS (YSBR-018), and the B-type Strategic Priority Program of CAS Grant No. XDB41000000. W.Y. was also funded by the Fundamental Research Funds for the Central Universities (grant No. YD3420002004), the Anhui Provincial Natural Science Foundation (grant No. 2008085 MD113), and the Joint Open Fund of Mengcheng National Geophysical Observatory (MENGO-202209). [PERSON] was funded by the foundation of the National Key Laboratory of Electromagnetic Environment, and the Fundamental Research Funds for the Central Universities. B.Y. was funded by the Joint Open Fund of Mengcheng National Geophysical Observatory (Grant No. MENGO-202207).