融合注意力机制的水储量异常重构与干旱识别

Reconstruction of Water Storage Anomalies and Drought Identification Using an Integrated Attention Mechanism

  • 摘要: 湖泊水文干旱的辨识对于科学评估水文干旱的规模、危害程度及其综合治理至关重要。长期监测陆地水储量异常(terrestrial water storage anomaly,TWSA)可量化湖泊及其流域的干旱特征。相比传统测量方法,重力恢复与气候实验( gravity recovery and climateexperiment,GRACE)卫星能精确监测TWSA变化,为湖泊水文干旱识别提供了空间对地观测手段。本研究以鄱阳湖为例,利用经过季节性调整和线性趋势去除的水文数据和GRACE估算的TWSA作为输入值,基于融合卷积神经网络和注意力机制的长短期记忆网络模型重构1982至2002年间的TWSA时间序列。最后,基于1982至2023年的TWSA时间序列识别鄱阳湖流域的水文干旱事件,并预估各干旱事件的潜在恢复时间。结果表明,使用重构数据成功识别鄱阳湖流域的水文干旱事件并量化其特征,并发现水文干旱的持续时间、恢复时间与其总体严重程度呈指数关系,为中小尺度流域干旱监测研究提供了一种新手段。

     

    Abstract: Objectives: The identification of lake hydrological droughts is crucial for the scientific evaluation of drought scale, severity, and comprehensive management. Long-term monitoring of terrestrial water storage anomalies (TWSA) enables the quantification of drought characteristics in lakes and their catchments. Compared to traditional measurement methods, the Gravity Recovery and Climate Experiment (GRACE) satellite can precisely monitor changes in TWSA, providing a spatial observation tool for identifying lake hydrological droughts. Methods: In this study, Poyang Lake was taken as a case study. Hydrological data with seasonal components and linear trends removed, along with TWSA estimated from GRACE, were used as input values. A long short-term memory (LSTM) network model integrated with a convolutional neural network (CNN) and attention mechanism was employed to reconstruct the TWSA time series from 1982 to 2002. Finally, combining GRACE observations and the reconstructed TWSA time series, hydrological drought events in the Poyang Lake basin from 1982 to 2023 were identified, and the potential recovery time of each drought event was estimated. Results: The results indicate that the reconstructed data successfully identified hydrological drought events in the Poyang Lake basin and quantitatively analyzed their characteristics. Conclusions: The duration and recovery time of hydrological droughts were found to have an exponential relationship with their overall severity. This method provides a new approach for drought monitoring research in medium and small-scale basins.

     

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