基于自注意力和门控循环神经网络的雷达回波外推算法研究

Improving radar echo extrapolation algorithms based on self-attention and gated recurrent neural networks

  • 摘要: 为提升现有神经网络对雷达回波序列的时、空特征提取能力,建立外推性能更优的时、空序列预测模型,开展雷达回波外推算法改进研究。基于深圳市气象局与香港天文台共同建立的雷达回波数据集,在数据处理层面,通过改进对雷达回波图像序列归一化的方法,提升了常用的5种时、空序列预测模型对强回波的预测水平;在模型算法层面,将两个联立的自注意力结构引入ST-LSTM结构,组成新的循环门控单元,并将这些循环门控单元进行堆叠,建立ST-SARNN模型。选用CSI和POD作为精度评价指标,进行模型对比分析得到:(1)改进的归一化方法提升了近几年内常用的5种时、空序列预测模型对强回波的预测水平。(2)加入自注意力的ST-SARNN模型对雷达回波的预测性能显著优于ConvLSTM、PredRNN和MIM等模型。改进的归一化方法能改变样本数据分布,并在一定程度上提升模型外推性能;自注意力结构能够有效挖掘雷达回波序列的时、空特征,进而改进神经网络的外推表现。

     

    Abstract: To enhance the spatiotemporal feature extraction ability of existing neural networks for radar echo sequences, establish a spatiotemporal sequence prediction model with better extrapolation performance, and carry out research on improving radar echo extrapolation algorithms. Based on the radar echo dataset jointly established by the Shenzhen Meteorological Bureau and the Hong Kong Observatory, at the data processing level, by improving the normalization method of radar echo image sequences, the prediction level of five commonly used spatiotemporal series prediction models for strong echoes has been improved. At the model algorithm level, two simultaneous self attention structures are introduced into the ST-LSTM structure to form a new cyclic gating unit, and these cyclic gating units are stacked to establish the ST-SARNN model. Selecting CSI and POD as accuracy evaluation indicators for model comparison analysis: (1) The improved normalization method has improved the prediction level of five commonly used spatiotemporal series prediction models in recent years for strong echoes. (2) The ST-SARNN model incorporating self attention has significantly better predictive performance than models such as ConvLSTM, PredRNN, and MIM for radar echoes. The improved normalization method can change the distribution of sample data and improve the model's extrapolation performance to a certain extent; The self attention structure can effectively mine the spatiotemporal features of radar echo sequences, thereby improving the extrapolation performance of neural networks.

     

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