The lower ionospheric disturbances associated with the Super Cyclonic Storm Amphan over the Bay of Bengal have been presented in this paper. The disturbances were observed by sub-ionospheric Very Low Frequency (VLF) radio signals from two navigational transmitters VTX and NWC, received at Cooch Behar, India. Strong variations of the nighttime signal amplitudes exceeding three times their standard deviations have been observed during the peak intensity phase of the cyclone. Morning terminator time in the VLF signal was influenced just after the cyclone peak and evening terminator time was influenced significantly after landfall. The radius of the strongly perturbed ionospheric region associated with the cyclone during its peak intensity has been estimated approximately between 500 and 1000 km from VLF observations.

本文介绍了与孟加拉湾上空的超级气旋风暴 Amphan 相关的较低电离层扰动。这些扰动是通过来自印度库奇比哈尔 (Cooch Behar) 的两个导航发射机 VTX 和 NWC 的亚电离层甚低频 (VLF) 无线电信号观测到的。在气旋的峰值强度阶段，已经观察到夜间信号幅度的强烈变化超过其标准偏差的三倍。VLF信号中的早晨终止时间在气旋高峰之后受到影响，而在登陆后晚上终止时间受到显着影响。据 VLF 观测估计，在其峰值强度期间与气旋相关的强烈扰动电离层区域的半径大约在 500 至 1000 公里之间。