Abstract

From 2011 to now a MAX-DOAS instrument developed by the Anhui Institute of Optics and Fine Mechanics institute is operated in Wuxi, China, which is along the Yangtze River. We determine the tropospheric vertical column densities (VCDs), near surface concentrations and vertical profiles of aerosols, NO₂, SO₂, HCHO from the MAX-DOAS observations using the DOAS method and profile retrieval algorithm (refered to as “PriAM”). We verified the results by comparing them with other independent techniques, such as sun photometer (Aeronet), a visibility meter and a long-path DOAS instrument. We acquire the cloud and aerosol conditions using a cloud classification scheme based on the MAX-DOAS observations. Based on the obtained results, we characterize the effect of the clouds on MAX-DOAS. Then we characterize the diurnal, annual and weekly variations of the trace gases and aerosols and validate the tropospheric trace gas VCDs derived from the Ozone Monitoring instrument (OMI) on the Aura satellite platform as well as the simulations from the IMAGES, CHIMERE and Lotos chemical transfer models. We analyse the agreement between MAX-DOAS, satellite and model datasets in different sky conditions. Besides the direct comparison with the satellite data, we also use the trace gas and aerosol profiles derived from MAX-DOAS to recalculate the air mass factor (AMF) for the satellite observations and to evaluate the corresponding improvement of the satellite VCDs. In some periods with strong aerosol pollution, we evaluate the effect of the aerosols on the satellite tropospheric AMF of the trace gases. Here should be noted that the aerosol effect on the AMF is not yet considered in the published satellite products, which cause appreciable errors of the tropospheric VCD of satellite products around polluted regions.

© 2015 Optical Society of America