Journal of Arid Meteorology ›› 2023, Vol. 41 ›› Issue (5): 783-791.DOI: 10.11755/j.issn.1006-7639(2023)-05-0783

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Study of soil moisture prediction method based on soil temperature and moisture persistence

WEI Sentao(), WANG Chenghai(), ZHANG Feimin, YANG Kai   

  1. Key Laboratory of Climate Resource Development and Disaster Prevention in Gansu Province, College of Atmospheric Sciences, Lanzhou University, Lanzhou 730000, China
  • Received:2023-04-03 Revised:2023-04-25 Online:2023-10-31 Published:2023-11-03

基于土壤温、湿度记忆性的土壤湿度预测方法研究

魏森涛(), 王澄海(), 张飞民, 杨凯   

  1. 甘肃省气候资源开发及防灾减灾重点实验室,兰州大学大气科学学院,甘肃 兰州 730000
  • 通讯作者: 王澄海(1961—),男,教授,主要从事青藏高原气候学、短期气候预测研究。E-mail:wch@lzu.edu.cn
  • 作者简介:魏森涛(1997—),男,硕士,主要从事短期气候预测研究。E-mail:weist20@lzu.edu.cn
  • 基金资助:
    国家自然科学基金项目(42175064);甘肃省自然科学基金项目(20JR10RA654)

Abstract:

Soil temperature and moisture are the important parameters in land surface process, and they are also important physical parameters in boundary conditions of atmospheric numerical model. This paper tried to obtain spatial-temporal evolution of soil moisture of the model through the machine learning method according to the memory characteristics of soil moisture. Considering the influence of soil temperature on soil moisture, the soil temperature and moisture of ERA5 reanalysis at depths of 0-7, 7-28, 28-100, 100-289 cm are used as predictors to predict changes of soil moisture on a monthly and seasonal scale based on convolutional neural networks (CNN). The results show that the method proposed in this paper is reliable and can effectively predict soil moisture 6 months in advance. The mean bias of predicted soil moisture in the shallow layer (0-28 cm) and deep layer (28-289 cm) is less than 0.05 and 0.02 m3·m-3, respectively. In the humid area, the mean bias is basically within 0.03 m3·m-3, showing a good effect.The prediction method and results presented in this paper can be used for both soil drought prediction and the initial and boundary conditions for numerical models.

Key words: convolutional neural network, soil temperature, soil moisture, influencing factors, prediction

摘要:

土壤温、湿度是陆面过程的重要参数,也是大气数值模式下边界条件的重要物理参量。由于土壤湿度的观测站点较少,土壤温湿度的空间资料较少,另外,土壤温湿度作为干旱预测的主要内容,需要知道未来时刻的土壤温湿度变化。因此,如何获得未来时刻土壤温湿度的时空变化具有重要意义。本文根据土壤湿度的记忆性特点,通过机器学习方法试图获得模式中土壤湿度的时空变化。采用卷积神经网络算法(Convolutional Neural Networks,CNN),考虑土壤温度对土壤湿度的影响,选取ERA5 0~7、7~28、28~100、100~289 cm深度层土壤温、湿度作为预测因子,对月、季尺度上土壤湿度变化进行预测。结果表明,本方法能提前6个月对土壤湿度进行可靠有效地预测;预测的浅层(0~28 cm)与深层(28~289 cm)土壤湿度平均偏差分别小于0.05、0.02 m3·m-3;在湿润区,平均偏差基本在0.03 m3·m-3以内,表现出较好的效果。本文的预测方法和结果,既可用于土壤干旱的预测,也可作为数值模式初边界场的形成。

关键词: 卷积神经网络, 土壤温度, 土壤湿度, 影响因素, 预测

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