Satellite Cloud Image Nowcasting Based on CGAFNet
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摘要: 卫星云图外推技术能及时掌握云团的运动轨迹和变化情况,为临近预报和灾害性天气的监测提供重要参考。然而,现有的云图预测方法存在难以捕捉小尺度云团发展、云图细节特征不清晰、预测结果逐渐模糊等问题,导致最终的预报效果不理想。为了有效提取卫星云图的时空信息,预报中小尺度云团的发展,利用FY-4A红外云图,以湖南区域为中心的中东部地区作为研究对象,从时空序列预测的角度出发,提出了一种卷积门控循环注意力融合网络(ConvGRU Attention Fusion Network,CGAFNet),并提出了主副损失(Primary and Secondary Loss,PaSLoss)作为模型的损失函数,构建了编-解码结构,更好地提取了卫星云图的时空信息。为验证网络框架的有效性,与三个典型网络进行对比实验,结果表明,CGAFNet在云图外推任务中均方根误差为10.00 K,结构相似性为0.74,峰值信噪比为31.43,该模型能准确预测云团的生消演变过程,在各项指标上均优于其它网络,证明该方法能获得更准确的预测精度,且具备良好的泛化能力。Abstract: Satellite cloud image extrapolation technology enables timely tracking of the movement and changes of cloud clusters, providing important references for nowcasting and severe weather monitoring. However, existing cloud image prediction methods face challenges such as difficulty in capturing the development of small-scale cloud clusters, unclear details in cloud images, and gradually blurred prediction results, leading to suboptimal forecasting performance. To effectively extract spatiotemporal information from satellite cloud images and forecast the development of mesoscale cloud clusters, this study utilized FY-4A infrared cloud images, focusing on the central and eastern regions of China with Hunan as the center. From the perspective of spatiotemporal sequence prediction, we proposed a convolutional gated recurrent attention fusion network (CGAFNet) and introduced primary and secondary loss (PaSLoss) as the model's loss function. An encoder-decoder structure was constructed to better extract spatiotemporal information from satellite cloud images. To validate the effectiveness of the network framework, we conducted comparative experiments with three typical networks. The results show that CGAFNet achieved a root mean squared error of 10.00 K, a structural similarity index of 0.74, and a peak signal-to-noise ratio of 31.43 in the cloud image extrapolation task. Outperforming other networks across various metrics, the model accurately predicted the evolution of cloud clusters, demonstrating that this method can achieve more accurate prediction accuracy and possesses good generalization ability.
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Key words:
- satellite cloud image /
- nowcasting /
- spatiotemporal prediction /
- fusion network /
- attention mechanism
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表 1 不同模型测试结果对比
方法 RMSE /K SSIM PSNR CGAFNet 10.00↓ 0.74↑ 31.43↑ GAN-CLSTM 10.58 0.69 31.1 ConvLSTM 10.16 0.71 30.91 Optical Flow 11.17 0.68 30.06 表 2 补充实验不同模型测试结果对比
方法 RMSE /K SSIM PSNR CGAFNet 9.78↓ 0.75↑ 31.46↑ GAN-CLSTM 10.14 0.74 31.22 ConvLSTM 9.95 0.7 30.09 Optical Flow 10.65 0.67 30.04 -
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