First observation‐based estimates of cloud‐free aerosol radiative forcing across China

Li, Zhanqing; Lee, Kwon-Ho; Wang, Yuesi; Xin, Jinyuan; Hao, WeiMin

doi:10.1029/2009jd013306

Cited by 122 publications

(71 citation statements)

References 59 publications

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“…Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia) (Huebert et al, 2003), the Asian Atmospheric Particle Environment (APEX) (Nakajima et al, 2003), the East Asian Study of Tropospheric Aerosols: An International Regional Experiment (EAST-AIRE) (Li et al, 2007) and cloud-free aerosol radiative forcing across China (Li et al, 2010). In recent years, many studies have been undertaken to assess the impact of aerosols on the climate in the Indian region Ramanathan et al, 2001b;Moorthy et al, 2005;Ramachandran, 2005aRamachandran, , 2005bTripathi et al, 2005;Pant et al, 2006;Niranjan et al, 2007;Babu et al, 2007;Sreekanth et al, 2007;Dey and Tripathi, 2008).…”

Section: Introductionmentioning

confidence: 99%

A long-term study of aerosol modulation of atmospheric and surface solar heating over Pune, India

Kumar¹,

Devara

2012

Tellus B: Chemical and Physical Meteorology

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A B S T R A C T Implications of aerosol characteristics, observed during a five-year (2004Á2009) period over Pune (a tropical urban location), to short-wave radiation budget are reported. A discrete ordinate radiative transfer (DISORT) model with a code, namely, Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART), has been used to carry out the radiative transfer computations. The validity of the method is demonstrated using independent ground-based remote sensing observations. Uncertainties in the estimates are also quantified. Clear-sky forcing reveals the points that include (1) Large negative bottom-of-the-atmosphere (BOA) forcing (more than (30 Wm (2 ) in all the months with peaks during October, December and March when the surface forcing exceeds Â (40 Wm (2 , and (2) Surface forcing values are higher for pre-monsoon months, while they are comparable for winter and post-monsoon months. The top-of-the-atmosphere (TOA) forcing is found to be negative during all the seasons. Large differences between TOA and BOA forcing during pre-monsoon, winter and post-monsoon indicate large absorption of radiant energy ( Â30 Wm (2 ) within the atmosphere during these seasons, thus increasing atmospheric heating by Â1 K/d. These values imply that aerosols have considerable impact on the atmosphereÁsurface system by causing substantial warming/cooling at the atmosphere/surface. This persistent trend in strong atmospheric absorption is likely to alter atmospheric thermodynamic conditions and thus affects circulation considerably.

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Section: Introductionmentioning

confidence: 99%

A long-term study of aerosol modulation of atmospheric and surface solar heating over Pune, India

Kumar¹,

Devara

2012

Tellus B: Chemical and Physical Meteorology

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“…They reported that unpolluted Aeolian dust (sourced from northwest China) is not largely absorbing. Li et al (2010) pointed out that despite intensive efforts to elucidate the optical properties and radiative forcing of aerosol across China, the northwestern region has been poorly sampled and thus neglected. Huang et al (2007Huang et al ( , 2009) studied the vertical distribution and heating rate of dust aerosol over the Taklimakan Desert, combining the Fu-Liou radiative transfer model with satellite observations.…”

Section: Introductionmentioning

confidence: 99%

Dust Aerosol Characteristics and Shortwave Radiative Impact at a Gobi Desert of Northwest China during the Spring of 2012

Shi

Xie

et al. 2014

Journal of the Meteorological Society of Japan

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The Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) project initiated an intensive field experiment on dust aerosols in Dunhuang from April 1 to June 12, 2012. Using sky radiometer measurements and conducting model simulations, we investigated the dust aerosol characteristics and its shortwave radiative impact on the regional climate. The daily averaged optical features of the aerosols markedly varied throughout the study period. High aerosol loading and predominantly coarse particulates were observed in the spring of 2012 ascribed to the influence of prevalent dust storm. The single scattering albedo at 500 nm (SSA 500 ) varied from 0.91 to 0.97 on dusty days and from 0.86 to 0.91 on dust-free days, indicating that the dust aerosols sourced from northwest China were not strongly absorbing. Surface radiation quantities estimated by the radiative transfer model excellently agreed with ground-based and satellite observations, with correlation coefficients exceeding 0.990 and mean differences ranging from −3.9 to 17.0 W m ), indicating strong cooling at the surface and moderate atmospheric warming. The monthly averaged ARFEs (ARFs per unit aerosol optical depth at 500 nm (AOD 500 )) at the surface were (−73.9 ± 11.6) W m ), comparable to previously obtained values in East Asia and India domains. The relations between the diurnal ARFs at the surface and top of the atmosphere (TOA) and the AOD 500 indicate that aerosol composition remained relatively stable at Dunhuang during the spring of 2012. The ARF at the TOA was positive for SSA 500 less than 0.85 or when the imaginary part at 500 nm exceeded 0.015.

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“…Therefore, it is necessary to characterize the aerosol optical properties based on observations in China, as many studies did in recent years at urban sites and in rural areas (e.g. Bergin et al, 2001;Xu et al, 2002Xu et al, , 2004Xu et al, , 2012Zhang et al, 2004Zhang et al, , 2015Yan, 2006;Xia et al, 2007;Yan et al, 2008;Andreae et al, 2008;He et al, 2009;Wu et al, 2009Wu et al, , 2012Wang et al, 2009;Li et al, 2010;Fan et al, 2010;Bai et al, 2011;Cai et al, 2011;Xiao et al, 2011;Zhuang et al, 2015;Li et al, 2015a, b;Yu et al, 2016). For example, Bergin et al (2001), and Zhuang et al (2015) presented the surface aerosol scattering and absorption properties in urban area of north and east China and they suggested that the annual mean 532 nm AAC (aerosol absorption coefficient) in Beijing was about 56 Mm −1 and it was 41-44 Mm −1 in YRD, which were much smaller than those in central to south-west China and in PRD (Wu et al, 2009;Cao et al, 2012;Tao et al, 2014) but much larger than those in rural and desert regions (Xu et al, 2002(Xu et al, , 2004Yan et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

The surface aerosol optical properties in the urban area of Nanjing, west Yangtze River Delta, China

et al. 2017

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Abstract. Observational studies of aerosol optical properties are useful for reducing uncertainties in estimations of aerosol radiative forcing and forecasting visibility. In this study, the observed near-surface aerosol optical properties in urban Nanjing are analysed from March 2014 to February 2016. Results show that near-surface urban aerosols in Nanjing are mainly from local emissions and the surrounding regions. They have lower loadings but are more scattering than aerosols in most cities in China. The annual mean aerosol extinction coefficient (EC), single-scattering albedo (SSA) and asymmetry parameter (ASP) at 550 nm are 381.96 Mm −1 , 0.9 and 0.57, respectively. The aerosol absorption coefficient (AAC) is about 1 order of magnitude smaller than its scattering coefficient (SC). However, the absorbing aerosol has a larger Ångström exponent (AAE) value, 1.58 at 470/660 nm, about 0.2 larger than the scattering aerosols (SAE). All the aerosol optical properties follow a near-unimodal pattern, and their values are mostly concentrated around their averages, accounting for more than 60 % of the total samplings. Additionally, they have substantial seasonality and diurnal variations. High levels of SC and AAC all appear in winter due to higher aerosol and trace gas emissions. AAE (ASP) is the smallest (largest) in summer, possibly because of high relative humidity (RH) which also causes considerably larger SC and smaller SAE, although intensive gas-toparticle transformation could produce a large number of finer scattering aerosols in this season. Seasonality of EC is different from the columnar aerosol optical depth. Larger AACs appear during the rush hours of the day while SC and backscattering coefficient (Bsp) only peak in the early morning. Aerosols are fresher in the daytime than at night-time, leading to their larger Ångström exponent and smaller ASP. Different temporal variations between AAC and SC cause the aerosols to be more absorbing (smaller SSA) in autumn, winter and around rush hours. ASP has a good quasi-log-normal growth trend with increasing SC when RH is below 60 %. The correlation between AAC and SC at the site is close but a little smaller than that in suburban Nanjing in spring. Atmospheric visibility decreases exponentially with increasing EC or SC, more sharply in spring and summer, and it could be further deteriorated with increasing SSA and ASP.

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First observation‐based estimates of cloud‐free aerosol radiative forcing across China

Cited by 122 publications

References 59 publications

A long-term study of aerosol modulation of atmospheric and surface solar heating over Pune, India

A long-term study of aerosol modulation of atmospheric and surface solar heating over Pune, India

Dust Aerosol Characteristics and Shortwave Radiative Impact at a Gobi Desert of Northwest China during the Spring of 2012

The surface aerosol optical properties in the urban area of Nanjing, west Yangtze River Delta, China

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