Assessment of the first indirect radiative effect of ammonium-sulfate-nitrate aerosols in East Asia

2016 ◽  
Vol 130 (3-4) ◽  
pp. 817-830
Author(s):  
Xiao Han ◽  
Meigen Zhang ◽  
Andrei Skorokhod
Keyword(s):  
East Asia ◽  
Ammonium Sulfate ◽  
Radiative Effect

scholarly journals Investigating the role of dust in ice nucleation within clouds and further effects on the regional weather system over East Asia – Part 2: modification of the weather system

2018 ◽  
Vol 18 (15) ◽  
pp. 11529-11545
Author(s):  
Lin Su ◽  
Jimmy C. H. Fung
Keyword(s):  
Surface Temperature ◽  
East Asia ◽  
South China ◽  
Radiative Forcing ◽  
Convective Precipitation ◽  
Radiative Effect ◽  
Weather System ◽  
Near Surface ◽  
Upper Troposphere ◽  
Atmospheric Instability

Abstract. An updated version of the Weather Research and Forecast model coupled with Chemistry (WRF-Chem) was applied to quantify and investigate the full effects of dust on the meteorological field over East Asia during March and April 2012. The performances of the model in simulating the shortwave and longwave radiation, surface temperature, and precipitation over East Asia are improved by incorporating the effects of dust in the simulations. The radiative forcing induced by the direct radiative effect of dust is greater than that by the dust-enhanced cloud radiative effect. The indirect effects of dust result in a substantial increase in ice clouds at the middle to upper troposphere and a reduction in liquid clouds at the low to mid-troposphere. The radiative forcing combined with the redistribution of atmospheric water vapor results in an overall decrease in near-surface temperature and an increase in temperature at the middle to upper troposphere over East Asia, leading to an inhibition of atmospheric instability over most land areas, but an enhancement of atmospheric instability over south China. Upon considering the effects of dust, convective precipitation exhibits an inhibition over areas from central to east China and an enhancement over south China. Meanwhile, the locations of non-convective precipitation are shifted due to the perturbation of cloud water path. The total amount of precipitation over East Asia remains unchanged; however, the precipitation locations are shifted. The precipitation can be enhanced or inhibited by up to 20 % at particular areas.

Photochemistry of toluene under high NOx, NH3 and humid conditions in the presence of inorganic seed particles: a smog chamber study for urban haze formation at East Asia

2020 ◽  
Author(s):  
Yong Lim ◽  
Duong Do ◽  
Hyun Jin ◽  
Jiwon Lee ◽  
Jin Young Kim
Keyword(s):  
East Asia ◽  
Ammonium Sulfate ◽  
Aqueous Phase ◽  
Thermodynamic Model ◽  
Large Fraction ◽  
Water System ◽  
Smog Chamber ◽  
High Concentration ◽  
Seed Particles ◽  
Inorganic Species

<p>High–concentration particulate matter (PM) at East Asia threatens human health and potentially alters climate. High levels of SO<sub>2</sub>, NO<sub>x</sub> and NH<sub>3</sub> emissions attribute the formation of inorganics including sulfates, nitrates and ammoniums in PM. Consequently, PM contains a large fraction of these inorganics, and aerosol liquid water (ALW) is considered to promote inorganic PM formation. A thermodynamic model has been used to estimate inorganic concentrations and a pH of PM because PM can be viewed as an ammonium-sulfate-nitrate-water system, which maintains thermodynamic equilibriums between the gas and particle phase and in the aqueous phase within particles. However, gas–particle partitioning of semivolatile inorganic species (i.e., NH<sub>3</sub>–NH<sub>4 </sub><sup>+ </sup>and HNO<sub>3</sub>–NO<sub>3</sub><sup>-</sup>) particularly influenced by organics and aqueous-phase secondary organic aerosol (aqSOA) formation in PM through multiphase chemistry are not well understood.</p><p>We conducted smog chamber experiments for OH-radical initiated reactions of toluene in the presence of ammonium sulfate seed particles under high NO<sub>x</sub>, NH<sub>3</sub> and humid conditions, which were similar to high-concentration haze conditions at Seoul, Korea. Measurements of inorganic concentrations in particles agree well with outputs of thermodynamic model simulations. The nitrate increase in seed particles is most prominent because ALW enhances the uptake of total HNO<sub>3</sub> photochemically formed from NO<sub>x</sub>. We identified methylglyoxal as a precursor for aqSOA formation. It appears that organics attribute ALW formation under deliquescence relative humidity for inorganic salts. We further investigated the response of particle mass concentrations to various NO<sub>x</sub> concentrations, which can be useful for NO<sub>x</sub> controls for PM reduction.</p>

scholarly journals Trans-Pacific transport and evolution of aerosols: Spatiotemporal characteristics and source contributions

2019 ◽  
Author(s):  
Zhiyuan Hu ◽  
Jianping Huang ◽  
Chun Zhao ◽  
Yuanyuan Ma ◽  
Qinjian Jin ◽  
...  
Keyword(s):  
North America ◽  
East Asia ◽  
West Coast ◽  
Mass Concentration ◽  
Western North America ◽  
Radiative Effect ◽  
The West ◽  
Aerosol Mass ◽  
Source Contributions ◽  
The Us

Abstract. Aerosols in the mid- and upper-troposphere have a long enough lifetime for trans-Pacific transport from East Asia to North America to influence air quality in the West Coast of the United States (US). Here, we conduct quasi-global simulations (180° W–180° E and 70° S–75° N) from 2010 to 2014 using an updated version of WRF-Chem (Weather Research and Forecasting model fully coupled with chemistry) to analyze the spatiotemporal characteristics and source contributions of trans-Pacific aerosol transport. We find that trans-Pacific total aerosols have a maximum mass concentration (about 15 𝜇g m−3) in the boreal spring with a peak between 3 and 4 km above the surface around 40° N. Sea-salt and dust dominate the total aerosol mass concentration below 1 km and above 4 km, respectively. About 80.8 Tg of total aerosols (48.7 Tg of dust) are exported annually from East Asia, of which 26.7 Tg of aerosols (13.4 Tg of dust) reach the West Coast of the US. Dust contributions from four desert regions in the Northern Hemisphere are analyzed using a tracer-tagging technique. About 4.9, 3.9, and 4.5 Tg year−1 of dust aerosol emitted from North Africa, Middle East and Central Asia, and East Asia, respectively, can be transported to the West Coast of the US. The trans-Pacific aerosols dominate the column-integrated aerosol mass (~ 65.5 %) and number concentration (~ 80 %) over the western North America. Radiation budget analysis shows that the inflow aerosols could contribute about 86.4 % (−2.91  W m−2) at the surface, 85.5 % (+1.36 W m−2) in the atmosphere and 87.1 % (−1.55 W m−2) at the top of atmosphere to total aerosol radiative effect over western North America. However, near the surface in the central and eastern North America, aerosols are mainly derived from local emissions and the radiative effect of imported aerosols decreases rapidly. This study motivates further investigations of the potential impacts of trans-Pacific aerosols from East Asia on regional air quality and hydrological cycle in North America.

scholarly journals Seasonal characteristics of emission, distribution and radiative effect of marine organic aerosols over the western Pacific Ocean: an analysis combining observations with regional modeling

2020 ◽  
Author(s):  
Jiawei Li ◽  
Zhiwei Han ◽  
Pingqing Fu ◽  
Xiaohong Yao
Keyword(s):  
Pacific Ocean ◽  
East Asia ◽  
Organic Aerosols ◽  
Organic Aerosol ◽  
Western Pacific ◽  
Western Pacific Ocean ◽  
Emission Flux ◽  
Radiative Effect ◽  
Marginal Seas ◽  
The Western Pacific

Abstract. Organic aerosols from marine sources over the western Pacific Ocean of East Asia were investigated by using an online-coupled regional chemistry-climate model RIEMS-Chem for the entire year 2014. Model evaluation against a wide variety of observations from research cruises and in-situ measurements demonstrated a good skill of the model in simulating temporal variation and spatial distribution of particulate matter with aerodynamic diameter less than 2.5 μm and 10 μm (PM2.5 and PM10), black carbon (BC), organic carbon (OC), and aerosol optical depth (AOD) in marine atmosphere. The inclusion of marine organic aerosols apparently improved model performance on OC aerosol concentration, reducing the normalized mean biases from −19 % to −13 % (KEXUE-1 cruise) and −21 % to −3 % (Huaniao Island) over the marginal seas of east China, and from 33 % to 5 % (Dongfanghong II cruise) and from −13 % to 3 % (Chichijima Island) over remote oceans of the western Pacific. It was found that marine primary organic aerosol (MPOA) accounted for majority of marine organic aerosol (MOA) mass in the western Pacific. High MPOA emission mainly occurred over the marginal seas of China and remote oceans of the western Pacific northeast of Japan. The seasonality of MPOA emission is determined by the combined effect of Chlorophyll-a (Chl-a) concentration and sea salt emission flux, exhibiting the maximum in autumn and the minimum in summer in terms of domain average over the western Pacific. The annual mean MPOA emission rate was estimated to be 0.16×10−2 μg m−2 s−1, yielding an annual MPOA emission of 0.78 Tg yr−1 over the western Pacific, which potentially accounted for approximately 8~12 % of global annual MPOA emission. The regional and annual mean near surface MOA concentration was estimated to be 0.27 μg m−3 over the western Pacific, with the maximum in spring and the minimum in winter, resulting from the combined effect of MPOA emission, dry and wet depositions. Marine secondary organic aerosol (MSOA) produced by marine biogenic VOCs (isoprene and monoterpene) was approximately 1~2 orders of magnitude lower than MPOA. The simulated annual and regional mean MSOA was 2.2 ng m−3, with the maximum daily mean value up to 28 ng m−3 over the western Pacific in summer. MSOA had a distinct summer maximum and winter minimum in the western Pacific, generally consistent with the seasonality of marine isoprene emission flux. In terms of annual mean, 26 % of the total organic aerosol concentration was contributed by MOA over the western Pacific, with an increasing importance of MOA from the marginal seas of China (13 %) to remote oceans of the western Pacific (42 %). MOA induced a minor direct radiative effect (DRE), with a domain and annual mean of −0.21 W m−2 at the top of the atmosphere (TOA) under all-sky condition over the western Pacific, whereas the mean indirect radiative effect (IRE) due to MOA at TOA (IREMOA) was estimated to be −4.2 W m−2. MSOA contributed approximately 6 % of the annual and regional mean IREMOA over the western Pacific, with the maximum seasonal mean contribution up to 14 % in summer, which meant MPOA dominated the IREMOA. It was noteworthy that the IREMOA accounted for approximately 32 % of that due to all aerosols over the western Pacific of East Asia, indicating an important role of MOA in perturbing cloud properties and shortwave radiation in this region.

scholarly journals Tropospheric Ozone Assessment Report: Present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation

Elem Sci Anth ◽  
2018 ◽  
Vol 6 ◽  
Author(s):  
A. Gaudel ◽  
O. R. Cooper ◽  
G. Ancellet ◽  
B. Barret ◽  
A. Boynard ◽  
...  
Keyword(s):  
East Asia ◽  
Atmospheric Chemistry ◽  
Model Evaluation ◽  
Tropospheric Ozone ◽  
Surface Ozone ◽  
Eastern China ◽  
Radiative Effect ◽  
Assessment Report ◽  
Spatial Coverage ◽  
Surface Observations

The Tropospheric Ozone Assessment Report (TOAR) is an activity of the International Global Atmospheric Chemistry Project. This paper is a component of the report, focusing on the present-day distribution and trends of tropospheric ozone relevant to climate and global atmospheric chemistry model evaluation. Utilizing the TOAR surface ozone database, several figures present the global distribution and trends of daytime average ozone at 2702 non-urban monitoring sites, highlighting the regions and seasons of the world with the greatest ozone levels. Similarly, ozonesonde and commercial aircraft observations reveal ozone’s distribution throughout the depth of the free troposphere. Long-term surface observations are limited in their global spatial coverage, but data from remote locations indicate that ozone in the 21st century is greater than during the 1970s and 1980s. While some remote sites and many sites in the heavily polluted regions of East Asia show ozone increases since 2000, many others show decreases and there is no clear global pattern for surface ozone changes since 2000. Two new satellite products provide detailed views of ozone in the lower troposphere across East Asia and Europe, revealing the full spatial extent of the spring and summer ozone enhancements across eastern China that cannot be assessed from limited surface observations. Sufficient data are now available (ozonesondes, satellite, aircraft) across the tropics from South America eastwards to the western Pacific Ocean, to indicate a likely tropospheric column ozone increase since the 1990s. The 2014–2016 mean tropospheric ozone burden (TOB) between 60°N–60°S from five satellite products is 300 Tg ± 4%. While this agreement is excellent, the products differ in their quantification of TOB trends and further work is required to reconcile the differences. Satellites can now estimate ozone’s global long-wave radiative effect, but evaluation is difficult due to limited in situ observations where the radiative effect is greatest.

scholarly journals Trans-Pacific transport and evolution of aerosols: spatiotemporal characteristics and source contributions

2019 ◽  
Vol 19 (19) ◽  
pp. 12709-12730 ◽  
Author(s):  
Zhiyuan Hu ◽  
Jianping Huang ◽  
Chun Zhao ◽  
Yuanyuan Ma ◽  
Qinjian Jin ◽  
...  
Keyword(s):  
North America ◽  
East Asia ◽  
West Coast ◽  
Mass Concentration ◽  
Western North America ◽  
Radiative Effect ◽  
The West ◽  
Aerosol Mass ◽  
Source Contributions ◽  
The Us

Abstract. Aerosols in the middle and upper troposphere have a long enough lifetime for trans-Pacific transport from East Asia to North America to influence air quality on the west coast of the United States (US). Here, we conduct quasi-global simulations (180∘ W–180∘ E and 70∘ S–75∘ N) from 2010 to 2014 using an updated version of WRF-Chem (Weather Research and Forecasting model fully coupled with chemistry) to analyze the spatiotemporal characteristics and source contributions of trans-Pacific aerosol transport. We find that trans-Pacific total aerosols have a maximum mass concentration (about 15 µg m−3) in the boreal spring with a peak between 3 and 4 km above the surface around 40∘ N. Sea salt and dust dominate the total aerosol mass concentration below 1 km and above 4 km, respectively. About 80.8 Tg of total aerosols (48.7 Tg of dust) are exported annually from East Asia, of which 26.7 Tg of aerosols (13.4 Tg of dust) reach the west coast of the US. Dust contributions from four desert regions in the Northern Hemisphere are analyzed using a tracer-tagging technique. About 4.9, 3.9, and 4.5 Tg year−1 of dust aerosol emitted from north Africa, the Middle East and central Asia, and East Asia, respectively, can be transported to the west coast of the US. The trans-Pacific aerosols dominate the column-integrated aerosol mass (∼65.5 %) and number concentration (∼80 %) over western North America. Radiation budget analysis shows that the inflow aerosols could contribute about 86.4 % (−2.91 W m−2) at the surface, 85.5 % (+1.36 W m−2) in the atmosphere, and 87.1 % (−1.55 W m−2) at the top of atmosphere to total aerosol radiative effect over western North America. However, near the surface in central and eastern North America, aerosols are mainly derived from local emissions, and the radiative effect of imported aerosols decreases rapidly. This study motivates further investigations of the potential impacts of trans-Pacific aerosols from East Asia on regional air quality and the hydrological cycle in North America.

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