基于TROPOMI卫星数据的长三角地区甲醛时空分布及影响因素分析

Spatial and temporal distribution of formaldehyde and its influencing factors in the Yangtze River Delta region based on TROPOMI satellite data

基于Sentenial-5P卫星上搭载的对流层监测仪(TROPOMI)2019—2021年对流层甲醛柱浓度数据,对长三角及其典型城市甲醛时空变化及影响因素进行了分析.结果表明:从空间变化特征来看,甲醛柱浓度分布呈现由长三角中部向四周逐渐降低的趋势,浓度高的地区主要集中在江苏、浙江和安徽交界处、江苏南部和安徽北部,甲醛柱浓度低的地区主要集中在浙江中部和南部.从时间变化特征来看,甲醛柱浓度年变化呈单峰结构,月平均浓度最高值(13.44×10^(15) molec·cm^(-2))出现在6月,最低值(8.79×10^(15) molec·cm^(-2))出现在4月.甲醛柱浓度具有显著的季节性变化特征,夏季平均最高,为12.35×10^(15) molec·cm^(-2),其次是秋季、冬季,春季平均最低为10.15×10^(15) molec·cm^(-2).影响甲醛的自然因素主要是气温和降水量,4个典型城市常州、合肥、苏州、无锡的甲醛柱浓度与气温的相关系数(r=0.82、0.39、0.84、0.77)大于与降水量的相关系数(r=0.61、0.29、0.64、0.68),气温影响更大;人为因素主要是汽车保有辆、工业数量和工业用电量,随着这些因素的增加,典型城市2020年比2019年甲醛柱浓度分别增长2.97%、0.65%、3.67和-5.06%.

Based on the tropospheric formaldehyde column concentrations from 2019 to 2021 from the Tropospheric Monitoring Instrument(TROPOMI)on board the Sentenial-5P satellite,we analyed the spatial and temporal variations of formaldehyde and the influencing factors in the Yangtze River Delta and its typical cities.As to the spatial variation,the distribution of formaldehyde column concentrations shows a trend of gradually decreasing from the central part of the Yangtze River Delta to the surrounding area,with high concentrations mainly concentrated in southern and northern Jiangsu,northern Anhui and the junction,and low formaldehyde column concentrations mainly concentrated in central and southern Zhejiang.In terms of temporal variation,the annual variation of formaldehyde column concentrations showed a single-peaked structure,with the highest monthly average value of 13.44×10^(15) molec·cm^(-2) occurring in June and the lowest value of 8.79×10^(15) molec·cm^(-2) in April.Formaldehyde column concentrations showed significant seasonal variation,with a mean maximum of 12.35×10^(15) molec·cm^(-2) in summer,followed by autumn and winter,and a mean minimum of 10.15×10^(15) molec·cm^(-2) in spring.The natural factors affecting formaldehyde were mainly temperature and precipitation.The correlation coefficients between column concentrations of formaldehyde and temperature(r=0.82,0.39,0.84,0.77)were greater than those with precipitation(r=0.61,0.29,0.64,0.68)in four typical cities,Changzhou,Hefei,Suzhou and Wuxi,with temperature having a greater influence;the main anthropogenic influence factors were vehicle number,industrial numbers and industrial electricity consumption,with these factors increasing the formaldehyde column concentration by 2.97%,0.65%,3.67%,-5.06%,respectively,in 2020 compared to those to 2019.