Spatial variability of TEC perturbations and ROTI during the 3 october 2024 X9.0 solar flare: a multi-station GNSS analysis
Abstract
This study investigates the spatially heterogeneous low-latitude ionospheric response to the 3 October 2024 X9.0 solar flare using GNSS observations from seven equatorial and low-latitude stations. TEC, quiet-time differential TEC ( Δ TEC ), and ROTI were analyzed under relatively quiet geomagnetic conditions ( Kp=1 –3). The flare peaked at 12:18 UT, and comparison with quiet-time conditions revealed Δ TEC perturbations of approximately 6–14% at several stations, with pronounced spatial differences. YKRO showed the largest positive perturbation at the flare peak, reaching 12.75 TECU (14.21%), whereas MBAR and CUSV exhibited negative perturbations of −10.98 TECU ( −10.77% ) and −6.14 TECU ( −9.29% ), respectively. However, substantial and sometimes larger Δ TEC variations occurred outside the flare interval, indicating that their magnitude alone cannot establish a flare-driven response. ROTI remained generally below 0.04 TECU min −1 during the flare, with stronger irregularity activity occurring predominantly after sunset. The results indicate a measurable and spatially heterogeneous ionospheric response temporally associated with the X9.0 flare, while highlighting the substantial contribution of intrinsic low-latitude variability. These findings emphasize the importance of multi-station observations and quiet-time normalization for robustly assessing solar-flare-associated ionospheric disturbances.
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BibTeX
@article{data2026spatial,
title = {{Spatial variability of TEC perturbations and ROTI during the 3 october 2024 X9.0 solar flare: a multi-station GNSS analysis}},
author = {Efrem Amanuel Data and Geto Kassa Setegn and Daniel Okoh},
journal = {Scientific Reports},
year = {2026},
month = oct,
doi = {10.1038/s41598-026-71943-y},
url = {https://www.nature.com/articles/s41598-026-71943-y},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Spatial variability of TEC perturbations and ROTI during the 3 october 2024 X9.0 solar flare: a multi-station GNSS analysis
AU - Efrem Amanuel Data
AU - Geto Kassa Setegn
AU - Daniel Okoh
PY - 2026
DA - 2026/10/02
JO - Scientific Reports
DO - 10.1038/s41598-026-71943-y
UR - https://www.nature.com/articles/s41598-026-71943-y
AB - This study investigates the spatially heterogeneous low-latitude ionospheric response to the 3 October 2024 X9.0 solar flare using GNSS observations from seven equatorial and low-latitude stations. TEC, quiet-time differential TEC ( Δ TEC ), and ROTI were analyzed under relatively quiet geomagnetic conditions ( K_p=1 –3). The flare peaked at 12:18 UT, and comparison with quiet-time conditions revealed Δ TEC perturbations of approximately 6–14% at several stations, with pronounced spatial differences. YKRO showed the largest positive perturbation at the flare peak, reaching 12.75 TECU (14.21%), whereas MBAR and CUSV exhibited negative perturbations of −10.98 TECU ( −10.77% ) and −6.14 TECU ( −9.29% ), respectively. However, substantial and sometimes larger Δ TEC variations occurred outside the flare interval, indicating that their magnitude alone cannot establish a flare-driven response. ROTI remained generally below 0.04 TECU min ^−1 during the flare, with stronger irregularity activity occurring predominantly after sunset. The results indicate a measurable and spatially heterogeneous ionospheric response temporally associated with the X9.0 flare, while highlighting the substantial contribution of intrinsic low-latitude variability. These findings emphasize the importance of multi-station observations and quiet-time normalization for robustly assessing solar-flare-associated ionospheric disturbances.
SN - 2045-2322
ER -