edu.ucar.opensky::articles:25225 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-24T22:50:28.587553 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d7wm1j1v Ionospheric topside diffusive flux and the formation of summer nighttime Ionospheric Electron Density Enhancement over Millstone Hill 2022-02-28T00:00:00Z publication https://n2t.org/ark:/85065/d7wm1j1v https://doi.org/10.1029/2021GL097651 Cai, Y. author Yue, X. author Wang, Wenbin author Zhang, S. author Liu, H. author Lei, J. author Ren, Z. author Chen, Y. author Ding, F. author Ren, D. author UCAR/NCAR - Library publisher Ionospheric F-region electron density is anomalously higher in the evening than during the daytime on many occasions in the summer in geomagnetic mid-latitude regions. This unexpected ionospheric diurnal variation has been studied for several decades. The underlying processes have been suggested to be related to meridional winds, topside influx arising from sunset ionospheric collapse, and other factors. However, substantial controversies remain unresolved. Using a numerical model driven by the statistical topside O+ diffusive flux from the Millstone Hill incoherent scatter radar data, we provide new insight into the competing roles of topside diffusive flux, neutral winds, and electric fields in forming the evening density peak. Simulations indicate that while meridional winds, which turn equatorward before sunset, are essential to sustain the daytime ionization near dusk, the topside diffusive flux is critically important for the formation and timing of the summer evening density peak. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. None eng geoscientificInformation