Vertical distributions of aerosol optical properties during the spring 2016 ARIAs airborne campaign in the North China Plain

Abstract

Abstract. Vertical distributions of aerosol optical properties derived from measurements made during 11 aircraft flights over the North China Plain (NCP) in May-June 2016 during the Air Chemistry Research In Asia (ARIAs) were analyzed. Aerosol optical data from in situ aircraft measurements show good correlation with ground-based measurements. The regional variability of aerosol optical profiles such as aerosol scattering and backscattering, absorption, extinction, single scattering albedo (SSA), and the Ångström exponent (α) are thoroughly characterized for the first time over the NCP. The SSA at 550 nm showed a regional mean value of 0.85 ± 0.02 with moderate to strong absorption and the α ranged from 0.49 to 2.53 (median 1.53), indicating both mineral dust and accumulation-mode aerosols. Most of the aerosol particles were located in the lowest 2 km of the atmosphere. We describe three typical planetary boundary layer (PBL) scenarios and associated transport pathways as well as the correlation between aerosol scattering coefficients and relative humidity (RH). Aerosol scattering coefficients decreased slowly with height in the clean PBL condition, but decreased sharply above the PBL under polluted conditions, which showed a strong correlation (R 2 ≥ 0.78) with ambient RH. Back-trajectory analysis shows that clean air masses generally originated from the distant northwestern part of China, while most of the polluted air masses were from the heavily polluted interior and coastal areas near the campaign region.

Assessing Measurements of Pollution in the Troposphere (MOPITT) carbon monoxide retrievals over urban versus non-urban regions

“…Observations from the Measurements of Pollution in the Troposphere (MOPITT) instrument onboard the NASA Terra satellite have been used for retrieving total column amounts and volume mixing ratio (VMR) profiles of carbon monoxide (CO) using both thermal-infrared (TIR) and near-infrared (NIR) measurements since March 2000. Besides the TIRonly and NIR-only products, the MOPITT multispectral TIR-NIR product is also provided, which has enhanced the sensitivity to near-surface CO (Deeter et al, 2011(Deeter et al, , 2013Worden et al, 2010). Since the start of the mission, the MOPITT CO retrieval algorithm has been improved and enhanced continuously (Worden et al, 2014).…”

“…MOPITT products are particularly useful for monitoring and analyzing air pollution over urban regions because of the enhanced retrieval sensitivity to near-surface CO and the long-term record (e.g., Clerbaux et al, 2008;Girach and Nair, 2014;Jiang et al, 2015Jiang et al, , 2018Kar et al, 2010;Tang et al, 2019;Worden et al, 2010;Li and Liu, 2011;He et al, 2013;Aliyu and Botai, 2018;Kanakidou et al, 2011). However, the performance of MOPITT retrievals over urban regions has not yet been validated systematically.…”

Vertical profiles of NO<sub>2</sub>, SO<sub>2</sub>, 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

“…Ding et al, 2009) in haze events has been studied with chemical transport modelling (e.g. L. Wang et al, 2012 and observations such as ground-based stations, mobile platforms (e.g. Zhu et al, 2016), aircraft (e.g.…”

“…transport patterns and mixing processes) is also critical for the formation of haze events (e.g. Miao et al, 2015;Wang et al, 2012;Li et al, 2007). Previous studies were usually based on surface measurements of trace gases and/or column densities derived from satellite observations.…”

In-situ vertical characteristics of optical properties and heating rates of aerosol over Beijing

“…The North China Plain (NCP) has raised great attention in recent decade because of the severe air pollution and high frequency of haze days. The causes of pollution have been widely investigated through surface measurements (Zhang et al, 2013;Zhang et al, 2015;Zhong et al, 2018), however only limited studies have considered the evolution of pollutants in vertical direction (Tian et al, 2019;Wang et al, 2018a). It was found the surface aerosol concentration over Beijing not only depended on the emission but the vertical structure of aerosol distribution was largely dependent on local and synoptic meteorological conditions (Ran et al, 2016a;Zhao et al, 2019), and regional transport will introduce enhanced aerosol https://doi.org/10.5194/acp-2019-780 Preprint.…”