主办单位:中国气象局沈阳大气环境研究所
国际刊号:ISSN 1673-503X
国内刊号:CN 21-1531/P

Journal of Meteorology and Environment ›› 2022, Vol. 38 ›› Issue (5): 34-41.doi: 10.3969/j.issn.1673-503X.2022.05.004

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Application of long short-term memory neural network (LSTM) model in low visibility forecast

Nan FANG1(),Guo-quan XIE1,*(),Xiao-jian RUAN2,Chen-ping REN1,Shu-jie JIANG3,Wei-wei ZHANG2   

  1. 1. Zhejiang Early Warning Center, Hangzhou 310052, China
    2. Zhejiang Meteorological Service Center, Hangzhou 310052, China
    3. Zhejiang Weather Modification Center, Hangzhou 310052, China
  • Received:2021-03-23 Online:2022-10-28 Published:2022-11-04
  • Contact: Guo-quan XIE E-mail:fjt901020@126.com;xiegq1@139.com

Abstract:

Based on the hourly meteorological observation data (relative humidity, wind speed, ground-air temperature difference, and visibility) and air quality index (AQI) data from 2015 to 2019 in Yiwu of Zhejiang province, we analyzed the distribution and meteorological conditions of low visibility (observed visibility lt; 10 km) in Yiwu.The Long Short-term Memory Neural Network (LSTM) was used to simulate the hourly visibility, and the simulation results with and without observed visibility as an input member were compared.According to the meteorological conditions of low visibility, the simulation period was divided into three periods (from November to February, from March to June, and from July to October).We compared the simulation performance in different periods and evaluated the model prediction steps.The results showed that the high humidity, high pollution, air temperature higher than the surface temperature, and low wind speed are the main meteorological characteristics influencing the low visibility weather in Yiwu.The LSTM has a good performance in simulating visibility at a single station.When the historical observed visibility has been used as an input parameter, the simulation accuracy can be greatly improved, with the root mean square error (RMSE) of 0.63 km, the mean absolute error (MAE) of 0.51 km, and the fitting goodness R2 of 0.99.Better simulation can be reached after dividing different periods, and the best simulation occurred in winter (from November to February) using the input elements selected in this study, with RMSE=2.35 km and MAE=1.46 km, and for low visibility weather, the RMSE_10km=1.81 km, MAE_10km=1.13 km, and R2=0.83.In the simulation from March to June, the simulation of low visibility without AQI as one input member performs better, which means that low visibility in Yiwu is dominated by foggy weather in this period.Adding too many variables does not necessarily improve the accuracy of the model.With the increase in the forecast step size, the simulation performs worse.When the forecast step size equals 3 h, R2 reaches 0.71 and the simulation result has no practical application significance.

Key words: Atmospheric Visibility, Long Short-term Memory Neural Network (LSTM), Forecast model, Air quality

CLC Number: