This discussion paper is a preprint. It is a manuscript under review for the journal Atmospheric Chemistry and Physics (ACP).
Vertical profiles of NO2, SO2, HONO, HCHO, CHOCHO, and aerosols derived from MAX-DOAS measurements at a rural site in the central-western North China Plain and their relation to emission sources and effects of regional transport
Yang Wang1,Steffen Dörner1,Sebastian Donner1,Sebastian Böhnke1,Isabelle De Smedt2,Russell R. Dickerson3,Zipeng Dong4,Hao He3,Zhanqing Li3,4,Zhengqiang Li5,Donghui Li5,Dong Liu6,Xinrong Ren3,7,Nicolas Theys7,Yuying Wang4,Yang Wang4,Zhenzhu Wang6,Hua Xu5,Jiwei Xu6,and Thomas Wagner1Yang Wang et al. Yang Wang1,Steffen Dörner1,Sebastian Donner1,Sebastian Böhnke1,Isabelle De Smedt2,Russell R. Dickerson3,Zipeng Dong4,Hao He3,Zhanqing Li3,4,Zhengqiang Li5,Donghui Li5,Dong Liu6,Xinrong Ren3,7,Nicolas Theys7,Yuying Wang4,Yang Wang4,Zhenzhu Wang6,Hua Xu5,Jiwei Xu6,and Thomas Wagner1
1Max Planck Institute for Chemistry, Mainz, Germany
2Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, Belgium
3Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park, Maryland, USA
4College of Global Change and Earth System Sciences, Beijing Normal University, Beijing, China
5Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences
6Key Laboratory of Atmospheric Composition and Optical Radiation, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei, China
7Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, Maryland, USA
1Max Planck Institute for Chemistry, Mainz, Germany
2Belgian Institute for Space Aeronomy (BIRA-IASB), Brussels, Belgium
3Department of Atmospheric and Oceanic Science and ESSIC, University of Maryland, College Park, Maryland, USA
4College of Global Change and Earth System Sciences, Beijing Normal University, Beijing, China
5Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences
6Key Laboratory of Atmospheric Composition and Optical Radiation, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei, China
7Air Resources Laboratory, National Oceanic and Atmospheric Administration, College Park, Maryland, USA
Received: 26 Oct 2018 – Accepted for review: 23 Nov 2018 – Discussion started: 26 Nov 2018
Abstract. A Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) instrument was deployed in May and June 2016 at a monitoring station (37.18° N, 114.36° E) in the suburban area of Xingtai (one of the most polluted cities in China) during the Atmosphere-Aerosol-Boundary Layer-Cloud (A2BC) and Air chemistry Research In Asia (ARIAs) joint experiments to derive tropospheric vertical profiles of NO2, SO2, HONO, HCHO, CHOCHO and aerosols. Aerosol optical depths derived from MAX-DOAS were found to be consistent with collocated sun-photometer measurements. Also the derived near-surface aerosol extinction and HCHO mixing ratio agree well with coincident visibility meter and in situ HCHO measurements, with mean HCHO near-surface mixing ratios of ~ 3.5 ppb. Underestimates of MAX-DOAS results compared to in situ measurements of NO2 (~ 60 %), SO2 (~ 20 %) are found expectedly due to vertical and horizontal inhomogeneity of trace gases. Vertical profiles of aerosols and NO2, SO2 are reasonably consistent with those measured by a collocated Raman Lidar and aircraft spirals over the station. The deviations can be attributed to differences in sensitivity as a function of altitude and substantial horizontal gradients of pollutants. Aerosols, HCHO, and CHOCHO profiles typically extended to higher altitudes (with 75 % integrated column located below ~ 1.4 km) than did NO2, SO2, and HONO (with 75 % integrated column below ~ 0.5 km) under polluted condition. Lifted layers were systematically observed for all species, (except HONO), indicating accumulation, secondary formation, or long-range transport of the pollutants at higher altitudes. Maximum values routinely occurred in the morning for NO2, SO2, and HONO, but around noon for aerosols, HCHO, and CHOCHO, mainly dominated by photochemistry, characteristic upslope/downslope circulation and PBL dynamics. Significant day-to-day variations are found for all species due to the effect of regional transport and changes in synoptic pattern analysed with HYSPLIT trajectories. Low pollution was often observed for air masses from the north-west (behind cold fronts), and high pollution from the southern areas such as industrialized Wuan. The contribution of regional transport for the pollutants measured at the site during the observation period was estimated to be about 20 % to 30 % for trace gases, and about 50 % for aerosols. In addition, agricultural burning events impacted the day-to-day variations of HCHO, CHOCHO and aerosols.
A MAX-DOAS instrument was operated to derive tropospheric vertical profiles of NO2, SO2, HONO, HCHO, CHOCHO and aerosols in the central-western North China Plain in May and June 2016. The MAX-DOAS results are verified by comparisons with collocated Raman Lidar, overpass aircraft measurements, sun-photometer, and in situ measurements. The contributions of regional transports and local emissions to the pollutants are evaluated based on case studies and statistic analysis.
A MAX-DOAS instrument was operated to derive tropospheric vertical profiles of NO2, SO2, HONO,...