MODIS卫星监测中国东部地区地面颗粒物的样本时间代表性分析

An Evaluation of the Temporal Representative of MODIS Application for Particulate Matter Assessment over Eastern China

选取2011年中国东部地区428个测站的PM10质量浓度资料,用Terra和Aqua MODIS AOD产品的时间分布作为指示数据,检验日、月、季、年时间尺度下,卫星过境时刻地面PM数据(SATPM)对地面所有时刻数据平均值(ALLPM)的代表性。结果发现,在东部大部分地区,SATPM与ALLPM的相对误差在±20%以内,且Aqua-MODIS代表性更好。此外,结合两颗卫星的数据,经拟合订正获得了新的日、年时间尺度上PM10质量浓度数据,将其与ALLPM的相关系数从0.87和0.83提高到0.90。此检验结果对于检验卫星数据反演的PM2.5的代表性也有一定指导意义。

The PM10 mass concentration from 428 ground sites in Eastern China in 2011 were used to investigate the temporal representative of satellites carrying MODIS for air quality monitoring. The daily, monthly, seasonal and yearly averaged ground measurements of PM10 mass concentration at the time when the satellite data is available （SATPM） were compared with the corresponding 24 hours averaged ground measurements （ALLPM）. The data with the Aqua-MODIS time are more close to ALLPM than those with Terra-MODIS time, and most relative errors fall into the range of ±20%, indicating a high reliability of temporal representative on Aqua time. Data from both satellites were incorporated together through a linear fitting to get the validated daily and yearly SATPM. The results show a better correlation and own lower root mean square errors （RMSE） with ALLPM. Because PM2.5 is more correlated with optical observations, the results are also of significant implications for the reliability of PM2.5 retrieval from satellite.