Analysis and Simulation Study of Visibility Evolution Characteristics in Chengdu

本文利用2020~2024年成都市温江气象站点的地面逐时气象数据，采用统计分析方法研究能见度时间演变规律及气象影响因子，检验能见度FSL模型在成都地区的适用性，并结合WRF模式进行能见度拟合研究。结果表明：成都市能见度呈显著年际改善趋势，年均值从2020年的9.32 km升至2024年的10.71 km，受其地理环境和气象条件影响，成都市夏季能见度最高，冬季最低，能见度日变化呈“单峰单谷”型，07时能见度最低，为5.93 km，17时峰值达15.90 km，相对湿度与能见度在日变化上呈强负相关，风速与能见度呈强正相关；能见度FSL模型在成都地区存在明显高估问题，改进后的FSL模型偏差显著减少，均方根误差(RMSE)降低了27.8 km；WRF模式中RUC陆面方案模拟精度最优，结合FSL模型，可完善WRF模式无能见度输出的功能。This paper utilizes hourly meteorological data from the Wenjiang meteorological station in Chengdu from 2020 to 2024, employing statistical analysis methods to study the temporal evolution of visibility and its influencing meteorological factors, examining the applicability of the visibility forecasting model FSL in the Chengdu area, and conducting visibility fitting research in conjunction with the WRF model. The results indicate that the visibility in Chengdu shows a significant interannual improvement trend, with the annual average increasing from 9.32 km in 2020 to 10.71 km in 2024. Affected by its geographical environment and meteorological conditions, Chengdu has the highest visibility in summer and the lowest in winter. The daily variation of visibility presents a “single peak and single valley” pattern, with the lowest visibility at 5.93 km at 07:00 and a peak value reaching 15.90 km at 17:00. There is a strong negative correlation between relative humidity and visibility in daily variation, while wind speed shows a strong positive correlation with visibility. The visibility FSL model exhibits a significant overestimation issue in the Chengdu area. The deviation of the improved FSL model has been significantly reduced, with the root mean square error (RMSE) decreasing by 27.8 km. Among the WRF models, the RUC land surface scheme has the best simulation accuracy; when combined with the FSL model, it can supplement the model’s functionality for outputs without visibility.