Observational Insights of Solar-Terrestrial Coupling from the Ionospheric and Surface Impacts during Solar Perturbations

We investigated three intense solar–terrestrial disturbance chains in 2022 viz. an X1.5 flare on February 15, an X1.0 + M8.7 flare based CME sequence on October 2 and a G3-geomagnetic storm driven by multiple CMEs on October 4 thereby aiming to diagnose how impulsive solar energy input cascades through the coupled ionosphere and troposphere system. Multi-platform data sets were used: GOES/SDO EUV–X-ray fluxes, ESA Solar Orbiter imagery, SWPC solar-wind and IMF parameters, ground-based ionosondes (TEC, NmF2, Ne, f0F2) and surface meteorological records. Results reveal a spectrum of responses governed by event type and magnetic field geometry. Immediate ionospheric impacts show a TEC bulge within < 5 min and peak NmF2/f0F2 at 16:00 UT. These were exclusive to the Earth-pointing X1.0 flare on October 2, neither the backside X1.5 flare nor the geomagnetic storm responsible for the production of such daytime surges. Ring current and TEC coupling was strongest on October 2. Bz minima (-8 nT) coincided with a 588 km s⁻¹ solar-wind stream, yielding the highest polynomial 0th and 1 st coefficients in TEC-Dst hysteresis loops. Storm scale forcing on October 4 manifested as sustained Kp = 7 and deep polar-cap absorption though the correlation of flare flux with Kp as low. Joule heating driven gravity-wave packets elevated high latitude surface pressure by 2–3 hPa and enlarged standard deviations of TEC and NmF2. Back-side eruptions on February 15 generated a negligible tropospheric or ionospheric change despite of a 3 Mkm prominence; SUVI-STEREO imagery confirmed the eruption’s off-disk trajectory thereby highlighting geo-effective line-of-sight requirements. Surface meteorology echoed upper-atmosphere forcing as the X1.05 flare embedded in the October 2 sequence cooled near-surface air and dew point while raising humidity and pressure, consistent with rapid modulation of the global atmospheric-electric circuit. Collectively, the study demonstrates that only Earth directed, magnetically connected sources drive coherent, multi-layer perturbations. Event specific lag signatures as in minutes for flare ionization, in hours for CME ion-drag heating and days for storm time gravity-wave coupling so these are critical to forecasting technology relevant ionospheric gradients and extreme weather precursors