Tropical Ionospheric Response to Very Severe Cyclonic Storm "BULBUL" Observed over SANYA (18.34°N, 109.62°E)

We present the tropical ionospheric response to a severe cyclonic storm, "BULBUL," observed from Ionosonde observations over "SANYA" (18.34° N, 109.62° E). The cyclone "BULBUL" developed as a low pressure on 5 November 2019 and intensified into a Very Severe Cyclonic Storm (VSCS) on 8 November 2019, and a landfall occurred on 9 November 2019 over West Bengal. This study utilizes Ionospheric parameters foF2 and hmF2 during the cyclone (5-11 November 2019). The cyclone period falls under quiet geomagnetic conditions (Kp < 3) and makes us investigate the lower atmospheric meteorological event's impacts on the ionosphere. Significant modulation has been found in hmF2 and foF2 during cyclone-intensified stages (SCS, VSCS, Land fall) from 7-9 November 2019. Low OLR and upward vertical velocity are observed at the matured stages, suggesting deep convection, generating Gravity Wave Oscillations. Local time profile reveals the severe suppression in foF2 during the intensification and land falling day of the cyclone, and reversely hmF2 shows an increasing trend. The peak value of hmF2 shifted from post-noon to prenoon hours during the progression of the cyclone (from SCS to VSCS and landfall). In addition, we observed strong gravity wave oscillations of about ~3 and 5 hours in foF2.