Regional Precipitation Nowcasting Based on CycleGAN Extension

Unusually, intensive heavy rain hit the central region of Korea on August 8, 2022. Many low-lying areas were submerged, so traffic and life were severely paralyzed. It was the critical damage caused by torrential rain for just a few hours. This event reminded us of the need for a more reliable regional precipitation nowcasting method. In this paper, we bring cycle-consistent adversarial networks (CycleGAN) into the time-series domain and extend it to propose a reliable model for regional precipitation nowcasting. The proposed model generates composite hybrid surface rainfall (HSR) data after 10 minutes from the present time. Also, the proposed model provides a reliable prediction of up to 2 hours with a gradual extension of the training time steps. Unlike the existing complex nowcasting methods, the proposed model does not use recurrent neural networks (RNNs) and secures temporal causality via sequential training in the cycle. Our precipitation nowcasting method outperforms convolutional long short-term memory (ConvLSTM) based on RNNs. Additionally, we demonstrate the superiority of our approach by qualitative and quantitative comparisons against MAPLE, the McGill algorithm for precipitation nowcasting by lagrangian extrapolation, one of the real quantitative precipitation forecast (QPF) models.