Automatic Spread F Detection and classification at Hainan Station of Chinese Meridian Project

The spread F phenomenon (SF), i.e., the spread characteristics on F trace in ionogram, is considered to be caused by ionospheric disturbances. The SF image features are considered to be corresponding to different physical mechanism. According to the URSI handbook of ionogram interpretation and reduction, depending on the shape of diffusion on ionogram, the SF all over the world could be divided into 4 types: FSF/RSF/MSF/BSF. However, we have found at low latitude, BSF is rare and strong RSF (SSF) is a major type. For the ionogram data obtained from Hainan Station (19.5°N, 109.1°E, magnetic 11°N), the Deep Learning technique is used for the image characteristics, making a model for automatic SF detection and classification at this station. No matter what the ionogram data formats or the ionosonde models, the model could automatic classify the SF as FSF/RSF/MSF/SSF for the first time.