Quantification of Vertical and Horizontal Wavelengths Associated With Atmospheric Gravity Waves (AGWs) During Extreme Tropical Cyclones Over the Indian Subcontinent

Abstract Atmospheric Gravity Waves (AGWs) play a crucial role in atmosphere‐ionosphere coupling. Tropical cyclones (TCs) are considered one of the potential sources of AGWs. This study investigates four extreme category tropical cyclones from the last two decades over the Indian subcontinent: VSCS Phailin (2013), ESCS Fani (2019), SuCS Amphan (2020) over the Bay of Bengal, and ESCS Tauktae (2021) in the Arabian Sea. The meteorological observations confirmed the presence of deep convective activity during these TCs, which reached higher tropospheric altitudes during the TC's duration. The low cloud‐top temperatures exhibited a positive correlation with the increasing lightning activity. Further, a notable increase in lightning activity was found during the intensification phases of the storm, particularly within the wind‐field regions in all four cases, which could have led to an intensification of TCs. Simultaneously, an enhancement in AGW activity occurred in the mesosphere‐lower thermosphere (MLT) region. Possibly, mesoscale convective system associated with the TC led to the formation of AGWs that propagated in both the vertical and horizontal domains to higher altitudes in the MLT region. The propagation of vertical and horizontal AGWs induced by TCs at higher altitudes has been validated and quantified by analyzing vertical temperature profiles obtained from SABER and day‐night band DNB imagery from VIIRS satellites. Both vertical and horizontal wavelengths of AGWs showed peak power of waves during the maximum intensity stages of TCs. Both vertical and horizontal components of AGWs are quantified for the first time over the Indian region.