Evaluation and application of multi-decadal visibility data for trend analysis of atmospheric haze

Abstract

Abstract. There are few multi-decadal observations of atmospheric aerosols worldwide. This study applies global hourly visibility (Vis) observations at more than 3000 stations to investigate historical trends in atmospheric haze over 1945-1996 for the US, and over 1973-2013 for Europe and eastern Asia. A comprehensive data screening and processing framework is developed and applied to minimize uncertainties and construct monthly statistics of inverse visibility (1/Vis). This data processing includes removal of relatively clean cases with high uncertainty, and change point detection to identify and separate methodological discontinuities such as the introduction of instrumentation. Although the relation between 1/Vis and atmospheric extinction coefficient (b ext ) varies across different stations, spatially coherent trends of the screened 1/Vis data exhibit consistency with the temporal evolution of collocated aerosol measurements, including the b ext trend of −2.4 % yr −1 (95 % CI: −3.7, −1.1 % yr −1 ) vs. 1/Vis trend of −1.6 % yr −1 (95 % CI: −2.4, −0.8 % yr −1 ) over the US for 1989-1996, and the fine aerosol mass (PM 2.5 ) trend of −5.8 % yr −1 (95 % CI: −7.8, 1973-2008 (r ∼ 0.9). Consistent "reversal points" from increasing to decreasing in SO 2 emission data are also captured by the regional 1/Vis time series (e.g., late 1970s for the eastern US, early 1980s for western Europe, late 1980s for eastern Europe, and mid 2000s for China). The consistency of 1/Vis trends with other in situ measurements and emission data demonstrates promise in applying these quality assured 1/Vis data for historical air quality studies.

Response of winter fine particulate matter concentrations to emission and meteorology changes in North China

“…The anthropogenic emission inventory used is the MACCity (MACC/CityZEN EU projects) emissions dataset, which provides monthly CO, NO x , SO 2 , volatile organic compounds (VOCs), BC, OC, and NH 3 emissions from different sectors for years between 1960 and 2020 (Granier et al, 2011). We compared the MACCity emission inventory for 2010 (Granier et al, 2011) with the MIX emission inventory for 2010 (Li et al, 2015) in the China region, and the magnitudes of emissions in China from these two datasets are very close. For example, the SO 2 emissions in China in 2010 were estimated to be 28 663 Gg in the MIX emission inventory and were 26 876.3 Gg in the MACCity emission inventory.…”

Fire and deforestation dynamics in Amazonia (1973–2014)

“…Fires also have a strong impact on visibility as shown in Figure 1: an image of Bolivian fires taken from the Moderate Resolution Imaging Spectroradiometer (MODIS) during the 2010 fire season. Visibility data sets are inherently more subjective than more conventional weather station records but have shown to be useful in a wide range of studies constraining regional air quality changes [Doyle and Dorling, 2002;Che et al, 2007;Chang et al, 2009], desert dust emissions [Mahowald et al, 2007], and global trends in atmospheric haze [Li et al, 2016].…”

A fully autonomous ozone, aerosol and nighttime water vapor lidar: a synergistic approach to profiling the atmosphere in the Canadian oil sands region

“…Tropospheric ozone, aerosols and water vapor are important atmospheric constituents affecting air quality and climate. Ozone is a short-lived climate pollutant (SLCP) and air pollutant that can have detrimental impacts on human health (Malley et al, 2015;Lippmann, 1991), agriculture (McKee, 1994) and ecosystems (Ashmore, 2005) when present at high enough concentrations. Tropospheric ozone is photochemically produced primarily from nitrogen oxides and volatile organic compounds (VOCs) from anthropogenic sources, is biogenically produced from forest fires (Aggarwal et al, 2018;Trickl et al, 2015) and can be enhanced through stratospheric/tropospheric transport (STT) events (Ancellet et al, 1991;Langford et al, 1996;Leblanc et al, 2011;Stohl and Trickl, 1999).…”

“…They affect the earth's climate by interacting with the sun and earth's radiation (Ramanathan et al, 2001) and by modifying clouds (Feingold et al, 2003;Twomey, 1977) and, depending on their size and the meteorological conditions, can travel over great distances around the globe . In high enough concentrations these particles can have dramatic effects on visibility (Li et al, 2016;Singh et al, 2017) and cause respiratory problems, particularly in those suffering from lung conditions such as asthma. This has been the motivation for several countries to adopt an air quality index (Kousha and Valacchi, 2015) to alert the public to respiratory dangers during pollution events.…”