安徽省电线积冰标准冰厚的气象估算模型

Establishment of Meteorological Model for Estimating Standard Ice Thickness in Anhui Province

  • 摘要: 基于逐步多元线性回归和人工神经网络两种方法,利用安徽省有电线积冰观测的15个气象台站建站至2008年的观测资料,建立了安徽省3个不同区域电线积冰标准冰厚的气象估算模型。结果表明:相比人工神经网络模型,逐步多元线性回归模型预测效果较好;在覆冰机理认识上,印证了影响标准冰厚主要是气温、湿度和风速3个因子的配置,其中气温是影响覆冰的最重要因子;平原和丘陵地区的标准冰厚受当日气象条件影响更多,而高山地区与前几日及当日的气象条件均密切相关,且26个气象因子 (1987—2008年资料) 构建的模型的预测效果好于24个气象因子长序列 (建站—2008年资料) 效果。最后利用最优模型推算各区域非观冰站电线积冰标准冰厚,为冰冻灾害的评估以及风险区划的开展提供了基础。

     

    Abstract: An extreme frozen ice and snow disaster brings severe losses in Anhui Province during early 2008. Some overhead transmission lines are destroyed seriously during this event. It is important to investigate the characteristics of ice accumulation and develop appropriate models to estimate the disaster, but the research doesn't go smoothly due to the lack of data. If a quantitative relationship can be built between the meteorological elements and the ice thickness by the wire icing observation data of fewer stations, the ice-covered mechanism can be understood better, which can also lay the foundation for disaster risk regionalization.Based on the long-term wire icing observation data and climate data of 16 meteorological stations in recent 50 years, several models are built by stepwise multiple linear regression and artificial neural networks, to calculate standard ice thickness of wire icing in Anhui Province.Through coordinated experiment, the optimal models built by stepwise multiple linear regression are confirmed which handle temperature, humidity, wind speed of the icing day, one day before and two days before. The models by artificial neural network perform better in simulating comparatively, but in the prediction they are very unstable, and less effective. The model driven by 26 meteorological factors (data from 1987 to 2008) perform better than the model driven by 24 factors (data of from 1960 to 2008). The best models are picked out by the results of simulating and predicting. And the absolute deviation is 1.1 mm to the north of the Huaihe River, 1.3 mm to the south of the Huaihe River, 6.6 mm in the area of high mountains, and the relative deviation rates of the three models are about 60%—70%. The result is better than other references. For the mechanism of icing, temperature, humidity and wind are key factors, among which temperature is the most influential one. The ice thickness of the plains and hilly areas are mainly affected by weather conditions of the day, while that of mountain areas are also affected by the weather conditions of a few days before. Finally, the ice-wire thickness at the meteorological stations without wire icing observation is calculated by the optimal model, which proves this method feasible.

     

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