Analyses of aerosol optical properties and direct radiative forcing over urban and industrial regions in Northeast China

Che, Huizheng; Zhao, Huiling; Wu, Yunfei; Xia, Xiangao; Zhu, Jun; Wang, Hong; Wang, Yaqiang; Sun, Junying; Yu, Jie; Zhang, Xiaoye; Shi, Guangyu

doi:10.1007/s00703-015-0367-3

Cited by 48 publications

(25 citation statements)

References 35 publications

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“…The bias attributes to the average AOD of the latter were from a whole day. Moreover, the result was similar to those of suburban and background stations in the literature; for example, yearly mean AODs are equal to 0.82 at 500 nm at Xianghe [39], about 0.6 at Shenyang [40] and about 0.50 ± 0.06 in the Bohai Rim economic zone [41]. …”

Section: Monthly Variations In Viirs Modis and Sun Photometer Aod Osupporting

confidence: 88%

Validation of VIIRS AOD through a Comparison with a Sun Photometer and MODIS AODs over Wuhan

et al. 2017

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Visible Infrared Imaging Radiometer Suite (VIIRS) is a next-generation polar-orbiting operational environmental sensor with a capability for global aerosol observations. A comprehensive validation of VIIRS products is significant for improving product quality, assessing environment quality for human life, and studying regional climate change. In this study, three-year (from 1 January 2014 to 31 December 2016) records of VIIRS Intermediate Product (IP) data and Moderate Resolution Imaging Spectroradiometer (MODIS) retrievals on aerosol optical depth (AOD) at 550 nm were evaluated by comparing them to ground sun photometer measurements over Wuhan. Results indicated that VIIRS IP retrievals were underestimated by 5% for the city. A comparison of VIIRS IP retrievals and ground sun photometer measurements showed a lower R 2 of 0.55 (0.79 for Terra-MODIS and 0.76 for Aqua-MODIS), with only 52% of retrievals falling within the expected error range established by MODIS over land (i.e., ±(0.05 + 0.15AOD)). Bias analyses with different Ångström exponents (AE) demonstrated that land aerosol model selection of the VIIRS retrieval over Wuhan was appropriate. However, the larger standard deviations (i.e., uncertainty) of VIIRS AODs than MODIS AODs could be attributed to the less robust retrieval algorithm. Monthly variations displayed largely underestimated AODs of VIIRS in winter, which could be caused by a large positive bias in surface reflectance estimation due to the sparse vegetation and greater surface brightness of Wuhan in this season. The spatial distribution of VIIRS and MODIS AOD observations revealed that the VIIRS IP AODs over high-pollution areas (AOD > 0.8) with sparse vegetation were underestimated by more than 20% in Wuhan, and 40% in several regions. Analysis of several clear rural areas (AOD < 0.2) with native vegetation indicated an overestimation of about 20% in the northeastern region of the city. These findings showed that the VIIRS IP AOD at 550 nm can provide a solid dataset with a high resolution (750 m) for quantitative scientific investigations and environmental monitoring over Wuhan. However, the performance of dark target algorithms in VIIRS was associated with aerosol types and ground vegetation conditions.

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Section: Monthly Variations In Viirs Modis and Sun Photometer Aod Osupporting

confidence: 88%

Validation of VIIRS AOD through a Comparison with a Sun Photometer and MODIS AODs over Wuhan

et al. 2017

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“…The largest AOD values (up to approximately 1.0) retrieved from the MODIS satellite were associated with anthropogenic pollution over northeastern China during the 2014 sampling period. These large values, which exceeded 0.6, were related to local air pollution from industrial areas (Che et al, 2015;. In contrast, the MODIS-Aqua results indicate that the smallest AOD values (as low as 0.1) at 550 nm were found over the Gobi desert in Inner Mongolia and were related to strong winter winds.…”

Section: The Spatial Distribution Of Aodmentioning

confidence: 79%

Observations and model simulations of snow albedo reduction in seasonal snow due to insoluble light-absorbing particles during 2014 Chinese survey

et al. 2017

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Abstract. A snow survey was carried out to collect 13 surface snow samples (10 for fresh snow, and 3 for aged snow) and 79 subsurface snow samples in seasonal snow at 13 sites across northeastern China in January 2014. A spectrophotometer combined with chemical analysis was used to quantify snow particulate absorption by insoluble light-absorbing particles (ILAPs, e.g., black carbon, BC; mineral dust, MD; and organic carbon, OC) in snow. Snow albedo was measured using a field spectroradiometer. A new radiative transfer model (Spectral Albedo Model for Dirty Snow, or SAMDS) was then developed to simulate the spectral albedo of snow based on the asymptotic radiative transfer theory. A comparison between SAMDS and an existing model -the Snow, Ice, and Aerosol Radiation (SNICAR) -indicates good agreements in the model-simulated spectral albedos of pure snow. However, the SNICAR model values tended to be slightly lower than those of SAMDS when BC and MD were considered. Given the measured BC, MD, and OC mixing ratios of 100-5000, 2000-6000, and 1000-30 000 ng g −1 , respectively, in surface snow across northeastern China, the SAMDS model produced a snow albedo in the range of 0.95-0.75 for fresh snow at 550 nm, with a snow grain optical effective radius (R eff ) of 100 µm. The snow albedo reduction due to spherical snow grains assumed to be aged snow is larger than fresh snow such as fractal snow grains and hexagonal plate or column snow grains associated with the increased BC in snow. For typical BC mixing ratios of 100 ng g −1 in remote areas and 3000 ng g −1 in heavy industrial areas across northern China, the snow albedo for internal mixing of BC and snow is lower by 0.005 and 0.036 than that of external mixing for hexagonal plate or column snow grains with R eff of 100 µm. These results also show that the simulated snow albedos by both SAMDS and SNICAR agree well with the observed values at low ILAP mixing ratios but tend to be higher than surface observations at high ILAP mixing ratios.

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“…In the previous research on the radiative forcing of Beijing, the ARF-BOA ranged from´32 to´144 W/m 2 , according to one-month data analysis [1]. While, for other cities in China, the ARF-BOA were different:´136.52 W/m 2 in Shenyang, Northeast China, and´26.28 W/m 2 in Tongyu, Northwest of China [6,38]. The ARF-BOA in Beijing could be comparable with that in the Middle East and Southwest Asia (annual average of´114 W/m 2 ) [39], but larger than in that (´56 to´96 W/m 2 ) of Karachi, a megacity in Pakistan [40,41].…”

Section: Aerosol Radiative Forcing Measurements By Sun-photometersmentioning

confidence: 97%

Analysis of Aerosol Radiative Forcing over Beijing under Different Air Quality Conditions Using Ground-Based Sun-Photometers between 2013 and 2015

et al. 2016

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Aerosol particles can strongly affect both air quality and the radiation budget of the atmosphere. Above Beijing, the capital city of China, large amounts of aerosols within the atmospheric column have caused the deterioration of local air quality and have influenced radiative forcings at both the top and the bottom of the atmosphere (BOA and TOA). Observations of aerosol radiative forcing and its efficiency have been made using two sun-photometers in urban Beijing between 2013 and 2015, and have been analyzed alongside two air quality monitoring stations' data by dividing air quality conditions into unpolluted, moderately polluted, and heavily polluted days. Daily average PM 2.5 concentrations varied greatly in urban Beijing (5.5-485.0 µg/m 3 ) and more than one-third of the analyzed period is classified as being polluted according to the national ambient air quality standards of China. The heavily polluted days had the largest bottom of atmosphere (BOA) and top of atmosphere (TOA) radiative forcings, but the smallest radiative forcing efficiencies, while the unpolluted days showed the opposite characteristics. On heavily polluted days, the averaged BOA aerosol radiative forcing occasionally exceeded´150 W/m 2 , which represents a value about three-times greater than that for unpolluted days. BOA aerosol radiative forcing was around two-to-three times as large as TOA aerosol radiative forcing under various air quality conditions, although both were mostly negative, suggesting that aerosols had different magnitudes of cooling effects at both the surface and the top of the atmosphere. Unpolluted days had the largest average values of aerosol radiative forcing efficiencies at BOA (and TOA) levels, which exceeded 190 W/m 2 (´70 W/m 2 ), compared with the lowest average values in heavily polluted days of around´120 W/m 2 (´55 W/m 2 ). These results suggest that the high concentrations of particulate matter pollution in the urban Beijing area had a strong cooling effect at both BOA and TOA levels.

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Analyses of aerosol optical properties and direct radiative forcing over urban and industrial regions in Northeast China

Cited by 48 publications

References 35 publications

Validation of VIIRS AOD through a Comparison with a Sun Photometer and MODIS AODs over Wuhan

Validation of VIIRS AOD through a Comparison with a Sun Photometer and MODIS AODs over Wuhan

Observations and model simulations of snow albedo reduction in seasonal snow due to insoluble light-absorbing particles during 2014 Chinese survey

Analysis of Aerosol Radiative Forcing over Beijing under Different Air Quality Conditions Using Ground-Based Sun-Photometers between 2013 and 2015

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