长三角地区颗粒物浓度时空分布特征

Temporal and Spatial Distribution Characteristics of Particulate Matter Concentration in the Yangtze River Delta

摘要: 本文利用2017年中分辨率成像光谱仪MODIS (moderate-resolution imaging spectroradiometer)资料研究了长三角地区气溶胶光学厚度(AOD)、细粒子比例(FMF)、大气柱的颗粒物浓度(CMC)的时空分布特征，并利用上述资料计算了地面处PM_2.5质量浓度。结果表明，长三角地区AOD平均为0.5，表现出南低北高的分布特征，其中，武汉、南昌、合肥、南京、杭州、上海为高值区，杭州以南地区为低值区；AOD表现出明显的季节变化特征，整体变化为南低北高的分布特征，其中，6月最大，12月最小。FMF平均为0.6，高低值交叉分布，高值区在长江中下游地区，低值区在上海、江苏、安徽中部和江西中部；FMF春、秋、冬季为“北低南高”，夏季为“北高南低”，其中，最大月为2月，最小月为5月。长三角地区CMC平均为30，表现为北高南低的分布特征，武汉、南昌、合肥三个地区之间相互连接，成为北部柱质量浓度高值区，其他地区为低值区；CMC的季节变化呈北高南低的分布，夏半年略高于冬半年，其最大月和最小月分别为6月、12月。长三角地区PM_2.5平均为40，表现为北高南低的分布特征，其中，高值主要分布在上海、江苏、安徽北部、武汉、南昌地区，低值主要分布在六安、长江中下游地区；PM_2.5具有明显季节变化，夏秋两季低于冬春两季。通过对比计算的PM_2.5与地面监测PM_2.5质量浓度，发现两者的相关系数平均值为0.69。

Abstract: This paper uses the data of the MODIS (moderate-resolution imaging spectroradiometer) in 2017 to study the temporal and spatial distribution characteristics of aerosol optical depth (AOD), fine particle fraction (FMF), and atmospheric particle concentration (CMC) in the Yangtze River Delta region. And using the above data to calculate the mass concentration of PM_2.5 on the ground, the results show that the average AOD in the Yangtze River Delta is 0.5, showing the distribution characteristics of low in the south and high in the north. Among them, Wuhan, Nanchang, Hefei, Nanjing, Hang-zhou, and Shanghai are high-value areas, and the area south of Hangzhou is low-value areas. AOD shows obvious seasonal changes, the overall change is low in the south and high in the north. Among them, June is the largest and December is the smallest. The average FMF is 0.6, and the high and low values are cross-distributed. The high-value areas are in the middle and lower reaches of the Yang-tze River, and the low-value areas are in Shanghai, Jiangsu, central Anhui, and central Jiangxi; FMF spring, autumn, and winter are “low north and high south”, and summer is “high north and low south”. Among them, the largest month is February and the smallest month is May. The average CMC in the Yangtze River Delta is 30, which is characterized by high north and low south. The three regions of Wuhan, Nanchang, and Hefei are connected to each other and become the high-value area of the northern column mass concentration, and the other areas are low-value areas. The seasonal variation of CMC is high in the north and low in the south. The summer half of the year is slightly higher than the winter half of the year. The maximum and minimum months are June and December, respectively. The average PM_2.5 in the Yangtze River Delta is 40, which is characterized by high north and low south. Among them, the high values are mainly distributed in Shanghai, Jiangsu, northern Anhui, Wuhan, and Nanchang, and the low values are mainly distributed in Lu’an and the middle and lower reaches of the Yangtze River. PM_2.5 has obvious seasonal changes, and summer and autumn are lower than winter and spring. By comparing the calculated mass concentration of PM_2.5 and ground monitoring PM_2.5, it is found that the average correlation coefficient between the two is 0.69.