基于MAX-DOAS测定大气紫外波段水汽的吸收及其对DOAS反演影响的评估  

Measurement of Water Vapor Absorption in the Ultraviolet Band Using MAX-DOAS and Evaluation of Its Influence on DOAS Retrieval

作　　者：任红梅 李昂[1] 胡肇焜 谢品华[1,2,3] 徐晋 黄业园 李晓梅 钟鸿雁 张海蓉 田鑫 任博 郑江一 王帅 柴文轩[5] REN Hong-mei;LI Ang;HU Zhao-kun;XIE Pin-hua;XU Jin;HUANG Ye-yuan;LI Xiao-mei;ZHONG Hong-yan;ZHANG Hai-rong;TIAN Xin;REN Bo;ZHENG Jiang-yi;WANG Shuai;CHAI Wen-xuan(Key Laboratory of Environmental Optical and Technology,Anhui Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Hefei 230031,China;Science Island Branch of Graduate School,University of Science and Technology of China,Hefei 230026,China;CAS Center for Excellence in Urban Atmospheric Environment,Institute of Urban Environment,Chinese Academy of Sciences,Xiamen 361021,China;Institutes of Physical Science and Information Technology,Anhui University,Hefei 230601,China;State Environmental Protection Key Laboratory of Quality Control in Environmental Monitoring,China National Environment Monitoring Centre,Beijing 100012,China)

机构地区：[1]中国科学院合肥物质科学研究院,安徽光学精密机械研究所,环境光学与技术重点实验室,安徽合肥230031 [2]中国科学技术大学研究生院科学岛分院,安徽合肥230026 [3]中国科学院区域大气环境研究卓越创新中心,福建厦门361021 [4]安徽大学物质科学与信息技术研究院,安徽合肥230601 [5]中国环境监测总站,国家环境保护环境监测质量控制重点实验室,北京100012

出　　处：《光谱学与光谱分析》2022年第10期3314-3320,共7页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(41775029);国家重点研发计划项目(2018YFC0213201);中国科学院合肥物质科学研究院院长基金项目(YZJJ2020QN5)资助。

摘　　要：大气水汽的吸收强度从微波区域到可见蓝光区域逐渐降低,然而在紫外波段的吸收却经常被人忽略。多轴差分吸收光谱(MAX-DOAS)技术是一种被动光学遥感技术,可以同时反演气溶胶、多种痕量气体(如NO_(2),SO_(2),HCHO,HONO等)以及水汽,常用于区域大气立体分布及输送监测,具有成本低、时间分辨率高、稳定、可实时监测等特点。水汽是一种重要的温室气体,在紫外波段反演一些痕量气体时水汽的吸收经常不被考虑,可能对紫外波段痕量气体的反演造成影响,从而产生系统误差。介绍了基于MAX-DOAS对紫外波段大气水汽的反演,于2020年6月1日—9月24日在西安乾县进行观测,通过选取最优反演波段,并将反演结果与可见蓝光波段的水汽进行对比,证实了紫外波段存在水汽吸收,评估了紫外水汽的吸收对同波段痕量气体反演的影响。首先,根据不同拟合波段反演的水汽均方根误差(RMS)以及水汽和O_(4)的吸收截面情况,选取紫外和可见蓝光波段水汽的最优反演波段分别为351~370和434~455 nm。其次,通过DOAS拟合得到紫外和可见蓝光波段O_(4)和H_(2)O的对流层差分斜柱浓度(DSCD),分别将紫外和可见波段的O_(4)DSCD和H_(2)O DSCD做相关性分析,两个波段O_(4)DSCD的相关系数r=0.85,H_(2)O DSCD的相关系数r=0.80。为消除不同波段的辐射传输差异,将同波段的H_(2)O DSCD和O_(4) DSCD作比值,两个波段H_(2)O DSCD/ODSCD的相关系数r=0.89。紫外和可见蓝光波段H_(2)O DSCD/O_(4) DSCD的高相关系数表明,即使在相对沿海城市水汽浓度较低的西安市,在363 nm附近的紫外波段同样存在水汽吸收,这将会对采用DOAS技术在紫外波段反演其他痕量气体造成影响。最后,分别对可能受紫外波段水汽吸收影响的气体(O_(4),HONO和HCHO)进行DOAS反演误差评估,紫外波段水汽的吸收将使O_(4) DSCD,HONO DSCD以及HCHO DSCD在DOAS拟合过程中增加,分别对应于+1.16%,+8.55%The absorption of atmospheric water vapor gradually weakens from the microwave to the visible band,but the absorption in the ultraviolet band has been ignored.Multi-AXis Differential Optical Absorption Spectroscopy(MAX-DOAS)is a passive optical remote sensing technology that can simultaneously retrieve a variety of trace gases such as NO_(2),SO_(2),HCHO,HONO and water vapor.It is often used for regional atmospheric three-dimensional distribution and transportation monitoring,and has the characteristics of low cost,high time resolution stability,and real-time monitoring.Water vapor is an important greenhouse gas,and the water vapor absorption in the ultraviolet band is often not considered when we retrieve trace gases,which may affect the retrieval of trace gases in the ultraviolet band,resulting in systematic errors.This study introduced the atmospheric water vapor retrieval in the ultraviolet band using MAX-DOAS observations in Qianxian,Xi’an,from June 1 to September 24,2020.The optimal retrieval band in ultraviolet and visible were selected andcompared.The comparison results confirmed the water vapor absorption in the ultraviolet band,and we also evaluated the influence of ultraviolet water vapor absorption on the retrieval of trace gases in the same band.First,the optimal retrieval bands for water vapor in the ultraviolet(351~370 nm)and visible blue bands(434~455 nm)were selected according to the root mean square(RMS)and the absorption cross-sections of H_(2)O and O_(4).Secondly,the O_(4) and H_(2)O DSCD in the ultraviolet and visible blue bands were obtained by DOAS fitting,and the correlation between the two bands was analyzed.The two bands’correlation coefficient of O_(4) and H_(2)O DSCD in the two bands were 0.85 and 0.80.The ratio of O_(4) and H_(2)O DSCD in the same band has also been analyzed,and the correlation coefficient in the two bands was 0.89.The high correlation coefficients of H_(2)O DSCD and the ratio of H_(2)O DSCD/O_(4)DSCD in the ultraviolet and visible blue bands indicate that even Xi�

关 键 词：多轴差分吸收光谱 紫外波段 水汽 误差评估 

分 类 号：X831[环境科学与工程—环境工程]