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    基于多源观测识别内蒙古沙尘天气

    Identifying dust events of Inner Mongolia based on multi-source observations

    • 摘要: 利用气象常规观测资料和环境站PM、AQI、NO2等数据,以及基于卫星资料的反演产品,使用随机森林算法和支持向量机算法进行梯度建模,识别内蒙古地区119个国家气象观测站是否发生沙尘天气,为提高识别的准确率和空间覆盖度,分别在气象常规观测资料的基础上融入了环境站数据和卫星产品,并对2011—2020年包头机场人工校验的沙尘、雾霾等记录进行了检验。对2011—2023年内蒙古64次沙尘过程、29次霾过程、151次大雾过程进行分析和建模。结果表明:气象要素中能见度、相对湿度、气压、露点温度、平均风速等要素,以及天气现象(浮尘、扬沙、沙尘暴、霾和雾等)对识别沙尘天气有较大的贡献,其中能见度、天气现象、相对湿度的贡献度分别是0.30、0.23、0.22,沙尘天气发生时相对湿度平均下降40%,平均风速上升2倍以上,而雾霾天气发生时相对湿度和平均风速的变化与沙尘天气相反,分别上升50%~70%和下降30%~50%。环境要素中贡献度由高到低排序分别为NO2、CO、AQI、PM10、PM、PM2.5、PM10_ratio,沙尘天气发生时AQI上升6倍,而雾霾天气仅为0.7~2.5倍,霾天气发生时NO2和CO浓度升高约2倍,而沙尘天气发生时NO2浓度平均下降66%。基于随机森林模型,计算出53.5%的相对湿度、1.4×105 μg·m-3的PM10、1.1 μg·m-3的CO、超过9.7 m·s-1的平均风速及其距同月的历史平均值升高1.2 m·s-1以上,是一组能区分沙尘和雾霾天气的阈值。通过先对气象数据建立随机森林模型,再对环境数据建立支持向量机模型,最终模型的覆盖度和准确率分别达到了92%和93%。

       

      Abstract: Using conventional meteorological observation data and environmental station PM,AQI,NO2 data,as well as inversion products based on satellite data,the gradient modeling idea of random forest and support vector machine algorithm was used to identify whether 119 national meteorological observation stations in Inner Mongolia have experienced sandstorm weather.To improve the accuracy and spatial coverage of identification,environmental station data and satellite products were integrated,and the manually verified records of sandstorm,haze,and other factors at Baotou Airport from 2011 to 2020 were tested.A study on 64 dust and sand processes,29 haze processes,and 151 heavy fog processes from 2011 to 2023 found that:1.Meteorological elements such as visibility,relative humidity,air pressure,dew point temperature,and average wind speed,as well as weather phenomena (floating dust,blowing sand,sandstorms,haze,fog,etc.),have a significant contribution to identifying dust and sand weather.The contributions of visibility,weather phenomena,and relative humidity are 0.3,0.23,and 0.22,respectively.When dust and sand weather occurs,the average relative humidity decreases by 40% and the average wind speed increases by more than 2 times.However,when haze weather occurs,the changes in relative humidity and average wind speed are opposite to those of dust and sand weather,with an increase of 50-70% and decrease of 30-50%.The contribution of environmental factors in descending order is NO2,CO,AQI,PM10,PM,PM2.5,PM10_ratio,During sandstorm weather,AQI increase by nearly 6 times,while during haze weather it was only 0.7-2.5 times.During haze weather,the concentrations of NO2 and CO increase by about 2 times,while during sandstorm weather,the average concentration of NO2 decrease by 66%.3.Using a random forest model,calculate 53.5% relative humidity,1.4×105 μg · m-3 PM10,1.1 μg · m-3 CO,average wind speed exceeding 9.7 m · s-1,and historical average increase of 1.2 m · s-1 from the same month is a set of thresholds that can distinguish between dust and haze weather.4.By first establishing a random forest model for meteorological data,and then establishing a support vector machine model for environmental data,the final coverage and accuracy of the model are 92% and 93%.

       

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