Improving WRF-Chem PM2.5 predictions by combining data assimilation and deep-learning-based bias correction

In numerical model simulations, data assimilation (DA) on the initial conditions and bias correction (BC) of model outputs have been proven to be promising approaches to improving PM2.5 (particulate matter with an aerodynamic equivalent diameter of ≤ 2.5 μm) predictions. This study compared the opti...

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Main Authors: Xingxing Ma, Hongnian Liu, Zhen Peng
Format: Article
Language:English
Published: Elsevier 2025-01-01
Series:Environment International
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Online Access:http://www.sciencedirect.com/science/article/pii/S0160412024007864
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author Xingxing Ma
Hongnian Liu
Zhen Peng
author_facet Xingxing Ma
Hongnian Liu
Zhen Peng
author_sort Xingxing Ma
collection DOAJ
description In numerical model simulations, data assimilation (DA) on the initial conditions and bias correction (BC) of model outputs have been proven to be promising approaches to improving PM2.5 (particulate matter with an aerodynamic equivalent diameter of ≤ 2.5 μm) predictions. This study compared the optimization effects of these two methods and developed a new scheme that combines DA and BC simultaneously. Four parallel experiments were conducted during winter 2019: a control experiment directly forecasted by WRF-Chem (experiment name: WRF-Chem); an experiment that assimilated in situ observations based on the GSI (Gridpoint Statistical Interpolation) system (WRF-Chem_DA); an experiment with deep-learning-based BC (WRF-Chem_BC); and an experiment considering the combination of DA on the initial conditions and BC (WRF-Chem_DA_BC). Statistically, the accuracy of PM2.5 predictions could be optimized by both DA and BC for the first 24-h period, and WRF-Chem_BC performed better than WRF-Chem_DA in the initial field, especially in the period of 10–24 h, while the best performance was achieved by combining BC and DA. Throughout the initial 24-h period, compared with the control experiment, the results of WRF-Chem_DA_BC (WRF-Chem_DA, WRF-Chem_BC) showed an improvement in terms of root-mean-square error, with reduction proportions varying from 38.90 % to 48.86 % (18.88 % to 32.44 %, 30.10 % to 46.08 %). Besides having the best optimization effect over the whole domain, the combined method also performed well in different regions: during the forecasting period of 0–24 h, the RMSEs decreased from 32 % to 62 %, 39 % to 57 %, 28 % to 40 %, and 30 % to 49 % in the Beijing–Tianjin–Hebei, Yangtze River Delta, Central China, and Sichuan Basin urban agglomerations, respectively.
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spelling doaj-art-c69c9893a3d04345a538ba093a67e7162025-01-24T04:44:01ZengElsevierEnvironment International0160-41202025-01-01195109199Improving WRF-Chem PM2.5 predictions by combining data assimilation and deep-learning-based bias correctionXingxing Ma0Hongnian Liu1Zhen Peng2School of Atmospheric Sciences, Nanjing University, Nanjing 210023, ChinaCorresponding author.; School of Atmospheric Sciences, Nanjing University, Nanjing 210023, ChinaSchool of Atmospheric Sciences, Nanjing University, Nanjing 210023, ChinaIn numerical model simulations, data assimilation (DA) on the initial conditions and bias correction (BC) of model outputs have been proven to be promising approaches to improving PM2.5 (particulate matter with an aerodynamic equivalent diameter of ≤ 2.5 μm) predictions. This study compared the optimization effects of these two methods and developed a new scheme that combines DA and BC simultaneously. Four parallel experiments were conducted during winter 2019: a control experiment directly forecasted by WRF-Chem (experiment name: WRF-Chem); an experiment that assimilated in situ observations based on the GSI (Gridpoint Statistical Interpolation) system (WRF-Chem_DA); an experiment with deep-learning-based BC (WRF-Chem_BC); and an experiment considering the combination of DA on the initial conditions and BC (WRF-Chem_DA_BC). Statistically, the accuracy of PM2.5 predictions could be optimized by both DA and BC for the first 24-h period, and WRF-Chem_BC performed better than WRF-Chem_DA in the initial field, especially in the period of 10–24 h, while the best performance was achieved by combining BC and DA. Throughout the initial 24-h period, compared with the control experiment, the results of WRF-Chem_DA_BC (WRF-Chem_DA, WRF-Chem_BC) showed an improvement in terms of root-mean-square error, with reduction proportions varying from 38.90 % to 48.86 % (18.88 % to 32.44 %, 30.10 % to 46.08 %). Besides having the best optimization effect over the whole domain, the combined method also performed well in different regions: during the forecasting period of 0–24 h, the RMSEs decreased from 32 % to 62 %, 39 % to 57 %, 28 % to 40 %, and 30 % to 49 % in the Beijing–Tianjin–Hebei, Yangtze River Delta, Central China, and Sichuan Basin urban agglomerations, respectively.http://www.sciencedirect.com/science/article/pii/S0160412024007864WRF-ChemBias correctionData assimilationPM2.5 concentrationsOptimization
spellingShingle Xingxing Ma
Hongnian Liu
Zhen Peng
Improving WRF-Chem PM2.5 predictions by combining data assimilation and deep-learning-based bias correction
Environment International
WRF-Chem
Bias correction
Data assimilation
PM2.5 concentrations
Optimization
title Improving WRF-Chem PM2.5 predictions by combining data assimilation and deep-learning-based bias correction
title_full Improving WRF-Chem PM2.5 predictions by combining data assimilation and deep-learning-based bias correction
title_fullStr Improving WRF-Chem PM2.5 predictions by combining data assimilation and deep-learning-based bias correction
title_full_unstemmed Improving WRF-Chem PM2.5 predictions by combining data assimilation and deep-learning-based bias correction
title_short Improving WRF-Chem PM2.5 predictions by combining data assimilation and deep-learning-based bias correction
title_sort improving wrf chem pm2 5 predictions by combining data assimilation and deep learning based bias correction
topic WRF-Chem
Bias correction
Data assimilation
PM2.5 concentrations
Optimization
url http://www.sciencedirect.com/science/article/pii/S0160412024007864
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AT zhenpeng improvingwrfchempm25predictionsbycombiningdataassimilationanddeeplearningbasedbiascorrection