利用OMI遥感数据研究中国区域大气NO_2

Characteristics of atmospheric NO_2 over China using OMI remote sensing data

利用臭氧观测仪(Ozone Monitoring Instrument,OMI)卫星遥感反演的NO2柱浓度数据,分析了自2004年以来中国地区对流层NO2柱浓度(TroNO2)和总NO2柱浓度(TotNO2)的时空特征及其影响的原因.中国区域平均TroNO2和TotNO2呈现上升的趋势,年平均分别增长了4.67%和2.21%.冬季大气中的NO2主要来自对流层人为排放的NOx.在华北地区、长江三角洲地区和珠江三角洲地区出现高值区,TroNO2和TotNO2的月变化和它们之间的比率呈V字型,表现出了强烈的人为活动影响模式.华北地区、长江三角洲地区呈逐渐增大的趋势,而珠江三角洲地区呈逐渐减小的趋势.在青藏高原区,呈现较稳定的周期变化,TroNO2和TotNO2的月变化和它们之间的比率呈抛物线,最大值常出现在夏季,表现出自然条件下的模式.四川盆地代表了另一种变化模式,影响因素较为复杂;TroNO2和TotNO2呈明显的相关性,特别是东部发达地区,TroNO2和TotNO2比率大于0.7,相关系数大于0.9.

The temporal-spatial characteristics of the tropospheric column NO2（TroNO2） and total column NO2（TotNO2） over China is analyzed using remote sensing data derived from OMI sensor.In general,the regional mean values of TroNO2 and TotNO2 have an increasing trend over China.The annual increasing rates are 4.67% and 2.21%,respectively.In addition,the TroNO2 and TotNO2 present annual variability.During the summer time,the TotNO2 has the largest value,while the TroNO2 has the smallest value.In contrast,TroNO2 has the largest value and the TotNO2 has a sub-peak value in the winter time.As the TroNO2 mainly comes from the troposphere in which human activity plays a dominant role,it indicates that the anthropogenic emission NOx is the main source of atmospheric NO2 in winter.The large values appear over northern China,Yangtze River Delta and Pearl River Delta regions,which is closely associated with urbanization and economic development.The variability of TroNO2 and TotNO2 as well as the ratio of TroNO2 and TotNO2 reflects the anthropogenic emission impact.For the change trend,the atmospheric NO2 is increasing over northern China and Yangtze River Delta regions,and is decreasing over Pearl River Delta region.Our results show that,the TroNO2 over northern China and Yangtze River Delta region were increased 23.78% and 25.73%,respectively,and the Pearl River Delta region was decreased 34.65% from late 2000 to late 2009.Over the Tibetan Plateau region,the TroNO2,TotNO2 and their ratio show a stable annual variability and a parabolic curve.The largest often appears in summertime,implying the pattern of natural emission.In Sichuan Basin,the NO2 shows another pattern,which is affected by more complex factors.TroNO2 and TotNO2 present close correlation,especially in the eastern industrial regions with larger correlation coefficients（correlation coefficients higher than 0.9 and ratios larger than 0.7）.