RR-Former: Rainfall-runoff modeling based on Transformer

Recently, the long short-term memory (LSTM) based rainfall-runoff models have achieved good performance and thus have received many attentions. In this paper, we propose a novel rainfall-runoff model named RR-Former based on the Transformer, which is entirely composed of attention mechanisms. Compared with a LSTM-based model, the architecture of RR-Former can connect two arbitrary positions in a time series process directly by using attention modules. It can strengthen or weaken the connection of two arbitrary positions and thus is more flexible than a LSTM-based model. Therefore, the RR-Former has potential to achieve better performance. By employing the Catchment Attributes and Meteorology for Large-Sample Studies (CAMELS) dataset, we test the performance of RR-Former in two tasks: individual rainfall-runoff modeling and regional rainfall-runoff modeling. In the first task, our RR-Former outperforms two LSTM-based sequence-to-sequence models significantly for 7-day-ahead runoff predictions. For example, the median and the mean of Nash–Sutcliffe efficiency for the 673 basins provided by our RR-Former achieve 0.8265 and 0.7904, respectively, while those provided by the benchmark model (the better one between two benchmark models) are 0.7448 and 0.6952, respectively. In the second task, our RR-Former also shows its power and suits for a big dataset better.