edu.ucar.opensky::articles:43780 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-24T17:47:22.237440 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.net/ark:/85065/d7gx4h0h The role of downward plasma diffusion in the ionospheric nighttime Weddell Sea Anomaly 2025-06-16T00:00:00Z publication https://n2t.net/ark:/85065/d7gx4h0h https://doi.org/10.1029/2025GL115318 Li, Q. author He, M. author Wang, Wenbin author Zhang, S. author Qian, Liying author Aa, E. author Wang, D. author UCAR/NCAR - Library publisher This study investigates the role of downward plasma diffusion in the ionospheric nighttime Weddell Sea Anomaly (WSA), characterized by an anomalous diurnal electron density peak in nighttime from the South Pacific to South America. Traditionally attributed to prolonged photoionization and ionospheric uplift during summer, the WSA is not reproduced by the latest Thermosphere Ionosphere Electrodynamics General Circulation Model. We introduce a data&#8208;driven flux approach to incorporate more realistic diffusive flux, significantly improving the model's ability to replicate key WSA features. Simulations show that topside plasma diffusion turns downward in the evening, peaking near midnight, contributing notably to the NmF2 enhancement. Around 22:00 local time, downward plasmaspheric diffusion becomes the dominant plasma source, rivaling or exceeding local photoionization (12.08 vs. 8.50&#160; at 22:30). These results offer new insight into the interplay of processes driving the WSA and underscore the importance of plasma diffusion in ionospheric dynamics. 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 <span style="font-family:Arial;font-size:10pt;font-style:normal;" data-sheets-root="1">Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.</span> None eng geoscientificInformation