Regional modeling of tropospheric NO<sub>2</sub> vertical column density over East Asia during the period 2000–2010: comparison with multisatellite observations

Abstract

Abstract. Satellite observations of the tropospheric NO 2 vertical column density (VCD) are closely correlated to, and thus can be used to estimate, surface NO x emissions. In this study, the NO 2 VCD simulated by a regional chemical transport model with emissions data from the updated Regional Emission inventory in ASia (REAS) version 2.1 were validated through comparison with multisatellite observations during the period 2000-2010. Rapid growth in NO 2 VCD (∼ 11 % year −1 ) driven by the expansion of anthropogenic NO x emissions was identified above the central eastern China (CEC) region, except for the period during the economic downturn. In contrast, slightly decreasing trends (∼ 2 % year −1 ) were identified above Japan accompanied by a decline in anthropogenic emissions. To systematically compare the modeled NO 2 VCD, we estimated sampling bias and the effect of applying the averaging kernel information, with particular focus on the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) data. Using the updated REAS, the modeled NO 2 VCD reasonably reproduced annual trends observed by multisatellites, suggesting that the rate of increase of NO x emissions estimated by the updated REAS inventory would be robust. Province-scale revision of emissions above CEC is needed to further refine emission inventories. Based on the close linear relationship between modeled and observed NO 2 VCD and anthropogenic NO x emissions, NO x emissions in 2009 and 2010, which were not covered by the updated REAS inventory, were estimated. NO x emissions from anthropogenic sources in China in 2009 and 2010 were determined to be 26.4 and 28.5 Tg year −1 , respectively, indicating that NO x emissions increased more than twofold between 2000 and 2010. This increase reflected the strong growth of anthropogenic emissions in China following the rapid recovery from the economic downturn from late 2008 until mid-2009. Our method consists of simple estimations from satellite observations and provides results that are consistent with the most recent inventory of emissions data for China.

Turnaround of Tropospheric Nitrogen Dioxide Pollution Trends in China, Japan, and South Korea

“…This is likely valid, because satellite NO 2 observations are closely correlated to surface NOx emissions due to the short lifetime of NOx in the troposphere. Anthropogenic NOx emissions and the tropospheric NO 2 VCD simulated by an air quality model for the CEC region, where the anthropogenic NOx emission was the dominant source of NOx, were strongly correlated, with a R 2 higher than 0.9 (Itahashi et al 2014). The annual population data used here were taken from United Nations (2015).…”

A 15-year record (2001–2015) of the ratio of nitrate to non-sea-salt sulfate in precipitation over East Asia

“…Recently, satellite observations have been widely used as a proxy for emissions data. The NO 2 column has been used to capture NO x emissions (e.g., Miyazaki et al, 2012;Mijling et al, 2013;Itahashi et al, 2014b;Han et al, 2015;Irie et al, 2016), and the SO 2 column has been used for SO 2 emissions (e.g., Lee et al, 2011;Li et al, 2010) and/or volcanic eruptions (e.g., Brenot et al, 2014). Several studies have indicated the importance of different technologies to control emissions (e.g., Li et al, 2010;Wang et al, 2015;Krotkov et al, 2016;van der A et al, 2017).…”

“…In our previous studies (Itahashi et al, 2014a(Itahashi et al, , 2015, which considered data obtained in 2000-2011, emissions from China exhibited a transition from a continuously increasing trend. NO x emissions in China have been rising steadily (Kurokawa et al, 2013;Itahashi et al, 2014b), whereas SO 2 emissions in China peaked in [2005][2006] and subsequently declined due to the introduction of flue-gas desulfurization systems in China's 11th Five-Year Plan (2006 (Kurokawa et al, 2013;Itahashi et al, 2012). Recently, it has been reported that NO x emissions in China declined after 2011-2012 (Irie et al, 2016;Xia et al, 2016;Krotkov et al, 2016;van der A et al, 2017).…”

A 15-year record (2001–2015) of the ratio of nitrate to non-seasalt sulfate in precipitation over East Asia

“…Recently, satellite observations have been widely used as a proxy for emissions data. NO 2 column have been used to capture NOx emissions (e.g., Miyazaki et al, 2012;Mijling et al, 2013;Itahashi et al, 2014b;Han et al, 2015;Irie et al, 2016) and SO 2 25 column for SO 2 emissions (e.g., Lee et al, 2011;Li et al, 2010) and/or volcanic eruptions (e.g., Brenot et al, 2014). Several studies have indicated the importance of different technologies to control emissions (e.g., Li et al, 2010;Wang et al, 2015;Krotkov et al, 2016;van der A et al, 2017).…”

“…In our previous studies (Itahashi et al, 2014a(Itahashi et al, , 2015, which considered data for 2000-2011, emission from China was shown to transition from a trend of continuous increase. NOx emission in China has been rising steadily (Kurokawa et al, 2013;Itahashi et al, 2014b), whereas SO 2 emission in China peaked in [2005][2006] and subsequently declined due to the introduction of flue-gas desulfurization systems in China's 11th Five-Year Plan (2006 (Kurokawa et al, 2013;5 Itahashi et al, 2012a). Recently, it has been reported that NOx emission in China declined after 2011(Irie et al, 2016Xia et al, 2016;Krotkov et al, 2016;van der A et al, 2017).…”