Detection of Sudden Ionospheric Disturbances due to Solar flares by monitoring the Very Low Frequency signal at Malda

Sudden Ionospheric disturbances due to solar flares were detected by monitoring the very low frequency (VLF) data. The observed flares were compared with the Geostationary Operational Environmental Satellite (GOES) X-ray data. It is observed that there is no time lag between the peaks of our VLF observation and GOES X-ray data in morning session but there is a time lag in the afternoon. It may be due to ionization and recombination effect.