Simulated contrasting influences of two La Niña Modoki events on aerosol concentrations over eastern China

Abstract

Using the Goddard Earth Observing System (GEOS)‐Chem model driven by GEOS‐4 assimilated meteorological data, the potential influence of two La Niña Modoki events on aerosol concentrations over eastern China is explored. The results indicate that the impact of La Niña Modoki on aerosol concentrations differs between strong and moderate events. During the mature phase of the strong event of 1998/1999, an anomalous dipole pattern is observed over eastern China, i.e., with increased aerosol concentrations in the south and reduced concentrations in the north. The dipole pattern in the moderate event of 2000/2001 is reversed, with reduced aerosol concentrations in the south and increased concentrations in north China. Additionally, decreased aerosol concentrations are seen in spring of the decaying phase for the 1998/1999 event, while in the decaying spring of the 2000/2001 event, the dipole is reversed relative to the mature phase. During the decaying summer, aerosol concentrations are found to increase over eastern China in the 1998/1999 event but not in the 2000/2001 event. These anomalous aerosol concentrations are mainly caused by changes in circulation associated with the two La Niña Modoki events. In contrast, the role of wet deposition is observed to be limited during the lifespan of these two events. It is also found that the potential influence of the two La Niña Modoki events on aerosol concentrations can be up to 20% of the climatological mean. This suggests that La Niña Modoki has an important role in determining the distribution of aerosol concentrations over eastern China.

Modulation of the ENSO on Winter Aerosol Pollution in the Eastern Region of China

“…This paper did not discuss the difference between the influence of EP‐El Niño and CP‐El Niño events on aerosols in ERC. Obviously, this topic is worthy to be discussed in a follow‐up study (Feng et al, , ).…”

Simulated coordinated impacts of the previous autumn North Atlantic Oscillation (NAO) and winter El Niño on winter aerosol concentrations over eastern China

“…Meteorology parameters, i.e., atmospheric temperature (Aw and Kleeman, 2003;Liao et al, 2015), boundary layer (Kleeman, 2008;Yang et al, 2016), wind (Zhu et al, 2012;Yang et al, 2014Yang et al, , 2017Feng et al, 2017), and humidity (Ding and Liu, 2014), show a non-negligible impact on regional aerosol concentrations (ACs) by affecting deposition and transportation processes. Moreover, the intraseasonal and interannual variations in climatic phenomena could affect the spatial and temporal accumulation as well as the distribution of AC due to the associated variations in circulation and rainfall anomalies.…”

“…The interannual variation of AC over East Asia is connected with the interannual variation of the East Asian winter monsoon (Jeong and Park, 2017;Lou et al, 2016Lou et al, , 2018Mao et al, 2017) and summer monsoon (EASM; Zhang et al, 2010;Zhu et al, 2012). The seasonal evolution of the El Niño-Southern Oscillation (ENSO) impacts the seasonal variations of AC over northern and south China (Feng et al, 2016a(Feng et al, , 2017. The AC variation in the US is influenced by the Pacific Decadal Oscillation (Singh and Palazoglu, 2012).…”

“…The North Atlantic Oscillation (NAO), reflecting largescale fluctuations in pressure between the subpolar low and subtropical high, is one of the most determinant and influential climate variability modes in the extratropical Atlantic Ocean (e.g., Hurrell, 1995;Gong et al, 2001;Visbeck et al, 2001). A negative (positive) polarity of the NAO is reflected by positive (negative) pressure anomalies over the high latitudes of the North Atlantic and negative (positive) pressure anomalies over the central North Atlantic.…”

“…A negative (positive) polarity of the NAO is reflected by positive (negative) pressure anomalies over the high latitudes of the North Atlantic and negative (positive) pressure anomalies over the central North Atlantic. Both the positive and negative phases of NAO are accompanied by large-scale modulations in the location and intensity of the North Atlantic jet stream and storm track (Gong et al, 2001;Li and Wang, 2003). The surface-layer wind could vary in association with changes in the jet stream because of the NAO's quasi-barotropic characteristics, resulting in varied Ekman heat transport and basin-wide variations in the underlying sea surface temperature (SST; Marshall et al, 2001;Wu et al, 2009;Wu and Wu, 2018).…”