全球高分辨率海洋预报系统中的SST预报偏差校正

Deviation Correction of the SST Prediction in Global High Resolution Ocean Prediction System

  • 摘要: 本文基于卫星遥感的观测海表面温度(Sea Surface Temperature,SST)数据和自然资源部第一海洋研究所全球0.1°分辨率海浪-潮流-环流耦合数值预报模式(The surface wave-tide-circulation coupled ocean model developed by First Institute of Oceanography,MNR,China,FIO-COM)的预报结果,采用线性回归模型和长短期记忆神经网络(Long Short-Term Memory,LSTM)对SST预报结果进行误差校正。利用2016—2021年的数据开展了一系列对比试验,线性回归模型基于局部线性的假设实现对下一时刻误差的预报,LSTM利用2016—2020年共56个月的历史偏差数据训练模型,使用2021年的数据进行检验。结果表明,线性回归模型和LSTM神经网络都可以改善预报结果,LSTM神经网络相对于线性回归模型的效果更好,SST误差降低70%左右;与线性回归模型相比,经LSTM校正后的各点的偏差的概率密度分布集中在0附近。LSTM方法在统计意义上优于线性拟合且结果更稳定,可进一步推广到海洋数值预报多要素偏差校正。

     

    Abstract: Based on the sea surface temperature (SST) from satellite remote sensing and prediction of global 0.1° wave-tide-circulation coupled ocean model developed by First Institute of Oceanography, MNR, China (FIO-COM), linear regression model and Long Short-term Memory (LSTM) neural network were used to correct the errors in the SST prediction. A series of comparative tests were carried out with the data from 2016 to 2021. The linear regression model, which was based on assumption of local linearity, predicted the error at the next moment. The LSTM was built and trained with historical deviation data in the 56 months from 2016 to 2020, and was tested with the data in 2021. The results show that both the linear regression model and the LSTM neural network can improve the prediction, but the latter performs better than the former, and the SST error is reduced by about 70%. Compared with the linear regression model, the probability density distribution of the deviation at each point after LSTM correction is concentrated around 0. The LSTM method is statistically better than the linear fitting and its results are more stable, and can be further applied to multi-factor deviation correction of ocean numerical prediction.

     

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