Oya用深度学习融合卫星多波段数据,提升全球降水实时估算精度。
Oya: Deep Learning for Accurate Global Precipitation Estimation
- 分两阶段用双U-Net模型,先检雨再定量估雨,解决雨/无雨样本不平衡问题。
- 基于GPM CORRA v07数据训练,在多颗静止卫星覆盖下实现准全球实时监测。
- 相比现有方法显著提升精度,尤其适用于地面观测稀疏的地区。
精确的降水估计对水文应用至关重要,尤其在地面观测网络稀疏、预报能力有限的全球南方地区。现有基于卫星的降水产品常仅依赖长波红外通道或使用易引入误差的数据校准,尤其在亚日尺度上表现不佳。本研究提出Oya,一种利用地球静止卫星可见光与红外(VIS-IR)全谱观测的新型实时降水反演算法。Oya采用两阶段深度学习架构,结合两个U-Net模型:一个用于降水检测,另一个用于定量降水估计(QPE),以应对雨/无雨事件间固有的数据不平衡问题。模型以高分辨率GPM Combined Radar-Radiometer Algorithm (CORRA) v07数据为真实标签进行训练,并预先在IMERG-Final反演结果上进行预训练,以增强鲁棒性并缓解因CORRA时间采样有限导致的过拟合。通过整合多颗地球静止卫星数据,Oya实现准全球覆盖,其性能优于现有区域及全球降水基准方法,为改善降水监测与预报提供了有前景的路径。
原文摘要 · Abstract (English)
Accurate precipitation estimation is critical for hydrological applications, especially in the Global South where ground-based observation networks are sparse and forecasting skill is limited. Existing satellite-based precipitation products often rely on the longwave infrared channel alone or are calibrated with data that can introduce significant errors, particularly at sub-daily timescales. This study introduces Oya, a novel real-time precipitation retrieval algorithm utilizing the full spectrum of visible and infrared (VIS-IR) observations from geostationary (GEO) satellites. Oya employs a two-stage deep learning approach, combining two U-Net models: one for precipitation detection and another for quantitative precipitation estimation (QPE), to address the inherent data imbalance between rain and no-rain events. The models are trained using high-resolution GPM Combined Radar-Radiometer Algorithm (CORRA) v07 data as ground truth and pre-trained on IMERG-Final retrievals to enhance robustness and mitigate overfitting due to the limited temporal sampling of CORRA. By leveraging multiple GEO satellites, Oya achieves quasi-global coverage and demonstrates superior performance compared to existing competitive regional and global precipitation baselines, offering a promising pathway to improved precipitation monitoring and forecasting.
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