Description: Sudden Stratospheric Warming (SSW) is considered one extreme of polar stratospheric dynamic variability. During this extreme circulation variability, sudden warming at the stratospheric levels is seen to occur within a few days. There is a weakening of mean flow at the stratospheric level due to the strong two-way nonlinear interactions between upward propagating planetary waves and the mean flow. Recent studies have shown that the upper atmosphere's response during a particular SSW event may differ from that observed during another SSW occurrence. More studies are required to comprehensively organize the effects of SSWs on the upper atmosphere, especially in the ionosphere. This work focuses on understanding the SSW's impact on ionosphere dynamics, especially at high and mid-latitudes combining datasets obtained from atmospheric and ionospheric measurements and modeling. The individual characteristics of an SSW event are analyzed using the meteorological parameters retrieved from the reanalysis data. The global Total Electron Content (TEC) maps and the ground magnetometer data are used to understand the ionospheric response during the SSW event. The forcing due to the atmosphere-ionosphere vertical coupling during the SSW event is studied using the Chemistry Transport Model of the Leibniz Institute of Atmospheric Physics (CTM-IAP). Ionospheric responses during these event periods are analyzed using the outputs from the CTM-IAP. The study details the plasma density variability in the ionosphere during an SSW event.