scholarly journals Column aerosol optical properties and aerosol radiative forcing during a serious haze-fog month over North China Plain in 2013 based on ground-based sunphotometer measurements

2013 ◽  
Vol 13 (11) ◽  
pp. 29685-29720 ◽  
Author(s):  
H. Che ◽  
X. Xia ◽  
J. Zhu ◽  
Z. Li ◽  
O. Dubovic ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
North China Plain ◽  
North China ◽  
Optical Parameters ◽  
Aerosol Radiative Forcing ◽  
Coarse Mode ◽  
Fine Mode ◽  
Rural Sites ◽  
Urban Sites ◽  
Aerosol Radiative

Abstract. In January 2013, North China Plain experienced several serious haze events. Cimel sunphotometer measurements at seven sites over rural, suburban and urban regions of North China Plain from 1 to 30 January 2013 were used to further our understanding of spatial-temporal variation of aerosol optical parameters and aerosol radiative forcing (ARF). It was found that Aerosol Optical Depth at 500 nm (AOD500 nm) during non-pollution periods at all stations was lower than 0.30 and increased significantly to greater than 1.00 as pollution events developed. The Angstrom exponent (Alpha) was larger than 0.80 for all stations most of the time. AOD500 nm averages increased from north to south during both polluted and non-polluted periods on the three urban sites in Beijing. The fine mode AOD during pollution periods is about a factor of 2.5 times larger than that during the non-pollution period at urban sites but a factor of 5.0 at suburban and rural sites. The fine mode fraction of AOD675 nm was higher than 80% for all sites during January 2013. The absorption AOD675 nm at rural sites was only about 0.01 during pollution periods, while ~0.03–0.07 and 0.01–0.03 during pollution and non-pollution periods at other sites, respectively. Single scattering albedo varied between 0.87 and 0.95 during January 2013 over North China Plain. The size distribution showed an obvious tri-peak pattern during the most serious period. The fine mode effective radius in the pollution period was about 0.01–0.08 μm larger than during non-pollution periods, while the coarse mode radius in pollution periods was about 0.06–0.38 μm less than that during non-pollution periods. The total, fine and coarse mode particle volumes varied by about 0.06–0.34 μm3, 0.03–0.23 μm3, and 0.03–0.10 μm3, respectively, throughout January 2013. During the most intense period (1–16 January), aerosol radiative forcing (ARF) at the surface exceeded −50 W m−2, −180 W m−2, and −200 W m−2 at rural, suburban, and urban sites, respectively. The ARF readings at the top of the atmosphere were approximately −30 W m−2 in rural and −40–60 W m−2 in urban areas. Positive ARF at the top of the atmosphere at the Huimin suburban site was found to be different from others as a result of the high surface albedo due to snow cover.

scholarly journals Column aerosol optical properties and aerosol radiative forcing during a serious haze-fog month over North China Plain in 2013 based on ground-based sunphotometer measurements

2014 ◽  
Vol 14 (4) ◽  
pp. 2125-2138 ◽  
Author(s):  
H. Che ◽  
X. Xia ◽  
J. Zhu ◽  
Z. Li ◽  
O. Dubovik ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
North China Plain ◽  
North China ◽  
Optical Parameters ◽  
Aerosol Radiative Forcing ◽  
Coarse Mode ◽  
Fine Mode ◽  
Rural Sites ◽  
Urban Sites ◽  
Aerosol Radiative

Abstract. In January 2013, North China Plain experienced several serious haze events. Cimel sunphotometer measurements at seven sites over rural, suburban and urban regions of North China Plain from 1 to 30 January 2013 were used to further our understanding of spatial-temporal variation of aerosol optical parameters and aerosol radiative forcing (ARF). It was found that Aerosol Optical Depth at 500 nm (AOD500 nm) during non-pollution periods at all stations was lower than 0.30 and increased significantly to greater than 1.00 as pollution events developed. The Angstrom exponent (Alpha) was larger than 0.80 for all stations most of the time. AOD500 nm averages increased from north to south during both polluted and non-polluted periods on the three urban sites in Beijing. The fine mode AOD during pollution periods is about a factor of 2.5 times larger than that during the non-pollution period at urban sites but a factor of 5.0 at suburban and rural sites. The fine mode fraction of AOD675 nm was higher than 80% for all sites during January 2013. The absorption AOD675 nm at rural sites was only about 0.01 during pollution periods, while ~0.03–0.07 and 0.01–0.03 during pollution and non-pollution periods at other sites, respectively. Single scattering albedo varied between 0.87 and 0.95 during January 2013 over North China Plain. The size distribution showed an obvious tri-peak pattern during the most serious period. The fine mode effective radius in the pollution period was about 0.01–0.08 μm larger than during non-pollution periods, while the coarse mode radius in pollution periods was about 0.06–0.38 μm less than that during non-pollution periods. The total, fine and coarse mode particle volumes varied by about 0.06–0.34 μm3, 0.03–0.23 μm3, and 0.03–0.10 μm3, respectively, throughout January 2013. During the most intense period (1–16 January), ARF at the surface exceeded −50 W m−2, −180 W m−2, and −200 W m−2 at rural, suburban, and urban sites, respectively. The ARF readings at the top of the atmosphere were approximately −30 W m−2 in rural and −40–60 W m−2 in urban areas. Positive ARF at the top of the atmosphere at the Huimin suburban site was found to be different from others as a result of the high surface albedo due to snow cover.

scholarly journals Radiative forcing of the desert aerosol at Ouarzazate (Morocco)

2018 ◽  
Vol 37 ◽  
pp. 03004
Author(s):  
Abdelouahid Tahiri ◽  
Mohamed Diouri
Keyword(s):  
Optical Properties ◽  
Atmospheric Aerosol ◽  
Radiative Forcing ◽  
Cloud Formation ◽  
Optical Parameters ◽  
Aerosol Radiative Forcing ◽  
Daily Average ◽  
Definition Of ◽  
Aerosol Radiative

The atmospheric aerosol contributes to the definition of the climate with direct effect, the diffusion and absorption of solar and terrestrial radiations, and indirect, the cloud formation process where aerosols behave as condensation nuclei and alter the optical properties. Satellites and ground-based networks (solar photometers) allow the terrestrial aerosol observation and the determination of impact. Desert aerosol considered among the main types of tropospheric aerosols whose optical property uncertainties are still quite important. The analysis concerns the optical parameters recorded in 2015 at Ouarzazate solar photometric station (AERONET/PHOTONS network, http://aeronet.gsfc.nasa.gov/) close to Saharan zone. The daily average aerosol optical depthτaer at 0.5μm, are relatively high in summer and less degree in spring (from 0.01 to 1.82). Daily average of the Angstrom coefficients α vary between 0.01 and 1.55. The daily average of aerosol radiative forcing at the surface range between -150W/m2 and -10 W/m2 with peaks recorded in summer, characterized locally by large loads of desert aerosol in agreement with the advections of the Southeast of Morocco. Those recorded at the Top of the atmosphere show a variation from -74 W/m2 to +24 W/m2

scholarly journals Global fine-mode aerosol radiative effect, as constrained by comprehensive observations

2016 ◽  
Vol 16 (13) ◽  
pp. 8071-8080 ◽  
Author(s):  
Chul E. Chung ◽  
Jung-Eun Chu ◽  
Yunha Lee ◽  
Twan van Noije ◽  
Hwayoung Jeoung ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Radiative Effect ◽  
Anthropogenic Aerosols ◽  
Anthropogenic Aerosol ◽  
Radiative Balance ◽  
Aerosol Radiative Forcing ◽  
Fine Mode ◽  
Natural Aerosols ◽  
Fine Mode Aerosol ◽  
Aerosol Radiative

Abstract. Aerosols directly affect the radiative balance of the Earth through the absorption and scattering of solar radiation. Although the contributions of absorption (heating) and scattering (cooling) of sunlight have proved difficult to quantify, the consensus is that anthropogenic aerosols cool the climate, partially offsetting the warming by rising greenhouse gas concentrations. Recent estimates of global direct anthropogenic aerosol radiative forcing (i.e., global radiative forcing due to aerosol–radiation interactions) are −0.35 ± 0.5 W m−2, and these estimates depend heavily on aerosol simulation. Here, we integrate a comprehensive suite of satellite and ground-based observations to constrain total aerosol optical depth (AOD), its fine-mode fraction, the vertical distribution of aerosols and clouds, and the collocation of clouds and overlying aerosols. We find that the direct fine-mode aerosol radiative effect is −0.46 W m−2 (−0.54 to −0.39 W m−2). Fine-mode aerosols include sea salt and dust aerosols, and we find that these natural aerosols result in a very large cooling (−0.44 to −0.26 W m−2) when constrained by observations. When the contribution of these natural aerosols is subtracted from the fine-mode radiative effect, the net becomes −0.11 (−0.28 to +0.05) W m−2. This net arises from total (natural + anthropogenic) carbonaceous, sulfate and nitrate aerosols, which suggests that global direct anthropogenic aerosol radiative forcing is less negative than −0.35 W m−2.

scholarly journals Effect of Vertical Profile of Aerosols on the Local Shortwave Radiative Forcing Estimation

Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 187
Author(s):  
Francisco Molero ◽  
Alfonso Javier Fernández ◽  
María Aránzazu Revuelta ◽  
Isabel Martínez-Marco ◽  
Manuel Pujadas ◽  
...  
Keyword(s):  
Vertical Distribution ◽  
Vertical Profile ◽  
Radiative Forcing ◽  
Accurate Information ◽  
Optical Parameters ◽  
Aerosol Radiative Forcing ◽  
Radiative Forcings ◽  
Lidar Measurements ◽  
Aerosol Types ◽  
Aerosol Radiative

In this work, the effect of the aerosol vertical distribution on the local shortwave aerosol radiative forcing is studied. We computed the radiative forcing at the top and bottom of the atmosphere between 0.2 and 4 microns using the libRadTran package and compared the results with those provided by AERONET (AErosol RObotic NETwork). Lidar measurements were employed to characterize the aerosol vertical profile, and collocated AERONET measurements provided aerosol optical parameters required to calculate its radiative forcing. A good correlation between the calculated radiative forcings and those provide by AERONET, with differences smaller than 1 W m−2 (15% of estimated radiative forcing), is obtained when a gaussian vertical aerosol profile is assumed. Notwithstanding, when a measured aerosol profile is inserted into the model, differences between radiative forcings can vary up to 6.54 W m−2 (15%), with a mean of differences = −0.74 ± 3.06 W m−2 at BOA and −3.69 W m−2 (13%), with a mean of differences = −0.27 ± 1.32 W m−2 at TOA due to multiple aerosol layers and aerosol types. These results indicate that accurate information about aerosol vertical distribution must be incorporated in the radiative forcing calculation in order to reduce its uncertainties.

scholarly journals Global direct aerosol radiative forcing, as constrained by comprehensive observations

2016 ◽  
Author(s):  
Chul E. Chung ◽  
Jung-Eun Chu ◽  
Yunha Lee ◽  
Twan van Noije ◽  
Hwayoung Jeoung ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Anthropogenic Aerosols ◽  
Radiative Balance ◽  
Aerosol Radiative Forcing ◽  
Aerosol Forcing ◽  
The Earth ◽  
Fine Mode ◽  
Natural Aerosols ◽  
The Vertical Distribution ◽  
Aerosol Radiative

Abstract. Aerosols directly affect the radiative balance of the Earth through absorption and scattering of solar radiation. Although the contributions of absorption (heating) and scattering (cooling) of sunlight have proved difficult to quantify, the consensus is that anthropogenic aerosols cool the climate, partially offsetting the warming by rising greenhouse gas concentrations. Recent estimates of global direct aerosol radiative forcing are −0.35 ± 0.5 Wm−2, and these estimates depend either entirely or heavily on aerosol simulation. Here, we integrate a comprehensive suite of satellite and ground-based observations to constrain total AOD, its fine-mode fraction, the vertical distribution of aerosols and clouds, and the co-location of clouds and overlying aerosols. We find that fine-mode forcing is −0.46 Wm−2 (−0.54 ~ −0.39 Wm−2). Fine-mode aerosols include sea salt and dust aerosols, and we find that these natural aerosols pose a very large cooling (−0.44 ~ −0.26 Wm−2) when constrained by observations. When the contribution of these natural aerosols is subtracted from the fine-mode forcing, the net becomes −0.10 (−0.28 ~ +0.05) Wm−2. The net forcing arises from carbonaceous, sulfate and nitrate aerosols. Despite uncertainties in the anthropogenic fraction of these aerosols, this −0.28 ~ +0.05 Wm−2 range compels the direct aerosol forcing to be near zero.

scholarly journals Size-resolved characterization of organic aerosol in the North China Plain: new insights from high resolution spectral analysis

2021 ◽  
Author(s):  
Weiqi Xu ◽  
Chun Chen ◽  
Yanmei Qiu ◽  
Conghui Xie ◽  
Yunle Chen ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
North China Plain ◽  
North China ◽  
Fine Particles ◽  
Large Fraction ◽  
Organic Aerosol ◽  
Size Distributions ◽  
The North ◽  
The Impact

Organic aerosol (OA), a large fraction of fine particles, has a large impact on climate radiative forcing and human health, and the impact depends strongly on size distributions. Here we...

scholarly journals The Impact of Changes in Cloud Water pH on Aerosol Radiative Forcing

2019 ◽  
Vol 46 (7) ◽  
pp. 4039-4048 ◽  
Author(s):  
S. T. Turnock ◽  
G. W. Mann ◽  
M. T. Woodhouse ◽  
M. Dalvi ◽  
F. M. O'Connor ◽  
...  
Keyword(s):  
Radiative Forcing ◽  
Cloud Water ◽  
Aerosol Radiative Forcing ◽  
Water Ph ◽  
The Impact ◽  
Aerosol Radiative
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