Measuring and modeling black carbon (BC) contamination in the SE Tibetan Plateau

Cao, Junji; Tie, Xuexi; Xu, Bin; Zhao, Zi-Long; Zhu, Chongshu; Li, Guohui; Liu, Suixin

doi:10.1007/s10874-011-9202-5

Cited by 87 publications

(67 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The strong monsoon precipitation removes BC from the atmosphere during the transport. The high Himalayas can partly block the further transport of emissions from South Asia to the Tibetan Plateau, although small local topographical features such as the Yarlung Tsangpo River valley can provide a gate for the pollution to enter the inner Tibetan Plateau (Cao et al, 2010). Elevated emissions from the west (or the northern part of South Asia) can take the pathways at middle and upper levels, but they have minimal contribution to deposition.…”

Section: Source Attributionmentioning

confidence: 99%

Carbonaceous aerosols recorded in a southeastern Tibetan glacier: analysis of temporal variations and model estimates of sources and radiative forcing

Wang

Cao

et al. 2015

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. High temporal resolution measurements of black carbon (BC) and organic carbon (OC) covering the time period of in an ice core over the southeastern Tibetan Plateau show a distinct seasonal dependence of BC and OC with higher respective concentrations but a lower OC / BC ratio in the non-monsoon season than during the summer monsoon. We use a global aerosol-climate model, in which BC emitted from different source regions can be explicitly tracked, to quantify BC source-receptor relationships between four Asian source regions and the southeastern Tibetan Plateau as a receptor. The model results show that South Asia has the largest contribution to the presentday (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005) mean BC deposition at the ice-core drilling site during the non-monsoon season (October to May) (81 %) and all year round (74 %), followed by East Asia (14 % to the non-monsoon mean and 21 % to the annual mean). The icecore record also indicates stable and relatively low BC and OC deposition fluxes from the late 1950s to 1980, followed by an overall increase to recent years. This trend is consistent with the BC and OC emission inventories and the fuel consumption of South Asia (as the primary contributor to annual mean BC deposition). Moreover, the increasing trend of the OC / BC ratio since the early 1990s indicates a growing contribution of coal combustion and/or biomass burning to the emissions. The estimated radiative forcing induced by BC and OC impurities in snow has increased since 1980, suggesting an increasing potential influence of carbonaceous aerosols on the Tibetan glacier melting and the availability of water resources in the surrounding regions. Our study indicates that more attention to OC is merited because of its non-negligible light absorption and the recent rapid increases evident in the ice-core record.

show abstract

Section: Source Attributionmentioning

confidence: 99%

Carbonaceous aerosols recorded in a southeastern Tibetan glacier: analysis of temporal variations and model estimates of sources and radiative forcing

Wang

Cao

et al. 2015

Atmos. Chem. Phys.

View full text Add to dashboard Cite

show abstract

“…An anthropogenic emission inventory of China developed from 1990 to 2005 shows that the BC emissions, and, therefore, presumably, concentrations, have increased since 2000 [11]. Most studies (e.g., [12,13]) in China have used filter-based techniques that measure bulk aerosol absorption rather than the BC mass concentrations directly. Previous studies indicate that key properties of the BC aerosol, that is the particle's concentration, size, shape and mixing state, vary in complex ways and that these properties depend on many interacting environmental factors [14,15].…”

Section: Introductionmentioning

confidence: 99%

Characteristics of Black Carbon Aerosol during the Chinese Lunar Year and Weekdays in Xi’an, China

et al. 2015

Self Cite

View full text Add to dashboard Cite

Black carbon (BC) aerosol plays an important role in climate forcing. The net radiative effect is strongly dependent on the physical properties of BC particles. A single particle soot photometer and a carbon monoxide analyser were deployed during the Chinese Lunar Year (CLY) and on weekdays at Xi'an, China, to investigate the characteristics of refractory black carbon aerosol (rBC). The rBC mass on weekdays (8.4 μg·m −3 ) exceeds that during the CLY (1.9 μg·m −3 ), presumably due to the lower anthropogenic emissions during the latter. The mass size distribution of rBC shows a primary mode peak at ~205 nm and a small secondary mode peak at ~102-nm volume-equivalent diameter assuming 2 g·cm −3 in void-free density in both sets of samples. More than half of the rBC cores are thickly coated during the CLY (fBC = 57.5%); the percentage is slightly lower (fBC = 48.3%) on weekdays. Diurnal patterns in rBC mass and mixing state differ for the two sampling periods, which are attributed to the distinct anthropogenic activities. The rBC mass and CO mixing ratios are strongly correlated with slopes of 0.0070 and 0.0016 μg·m

show abstract

“…Over the Indian Himalayan foothills, high concentrations of BC were related to the boundary layer dynamics and to human activities in the adjoining valley (Pant et al, 2006). Although the high peaks of the Himalaya appear to block the transport of BC particles to the TP, the Yarlung Tsangpo River valley acts as a "leaking wall" to contaminate the southeast TP (Cao et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Similarities and differences of aerosol optical properties between southern and northern sides of the Himalayas

Panday

et al. 2014

Atmos. Chem. Phys.

View full text Add to dashboard Cite

Abstract. The Himalaya mountains along the southern edge of the Tibetan Plateau act as a natural barrier for the transport of atmospheric aerosols from the polluted regions of South Asia to the main body of the Tibetan Plateau. In this study, we investigate the seasonal and diurnal variations of aerosol optical properties measured at two Aerosol Robotic Network (AERONET) sites on the southern side of the Himalaya (Pokhara, 812 m above sea level (a.s.l.) and EVK2-CNR, 5079 m a.s.l. in Nepal) and one on the northern side (Qomolangma (Mt. Everest) station for Atmospheric and Environmental Observation and Research, Chinese Academy of Sciences (QOMS_CAS) in Tibet, 4076 m a.s.l. in China). While observations at QOMS_CAS and EVK2-CNR can generally be representative of a remote background atmosphere, Pokhara is a lower-elevation suburban site with much higher aerosol load due to both the influence of local anthropogenic activities and to its proximity to the Indo-Gangetic Plains. The annual mean aerosol optical depth (AOD) during the investigated period was 0.05 at QOMS_CAS, 0.04 at EVK2-CNR and 0.51 at Pokhara, respectively. Seasonal variations of aerosols are profoundly affected by large-scale atmospheric circulation. Vegetation fires, peaking during April in the Himalayan region and northern India, contribute to a growing fine mode AOD at the three stations. Dust transported to these sites, wind erosion and hydrated/cloudprocessed aerosols lead to an increase in coarse mode AOD during the monsoon season at QOMS_CAS and EVK2-CNR. Meanwhile, coarse mode AOD at EVK2-CNR is higher than at QOMS_CAS in August and September, indicating that the transport of coarse mode aerosols from the southern to the northern side may be effectively reduced. The effect of precipitation scavenging is clearly seen at Pokhara, which sees significantly reduced aerosol loads during the monsoon season. Unlike the seasonal variations, diurnal variations are mainly influenced by meso-scale systems and local topography. The diurnal pattern in precipitation appears to contribute to diurnal changes in AOD through the effect of precipitation scavenging. AOD exhibits diurnal patterns related to emissions in Pokhara, while it does not at the other two high-altitude sites. At EVK2-CNR, the daytime airflow carries aerosols up from lower-altitude polluted regions, leading to increasing AOD, while the other two stations are less influenced by valley winds. Surface heating influences the local convection, which further controls the vertical aerosol exchange and the diffusion rate of pollution to the surrounding areas. Fine and coarse mode particles Published by Copernicus Publications on behalf of the European Geosciences Union. C. Xu et al.: Similarities and differences of aerosol optical propertiesare mixed together on the southern side of the Himalaya in spring, which may lead to the greater inter-annual difference in diurnal cycles of Ångström exponent (AE) at EVK2-CNR than that at QOMS_CAS.

show abstract

Measuring and modeling black carbon (BC) contamination in the SE Tibetan Plateau

Cited by 87 publications

References 34 publications

Carbonaceous aerosols recorded in a southeastern Tibetan glacier: analysis of temporal variations and model estimates of sources and radiative forcing

Carbonaceous aerosols recorded in a southeastern Tibetan glacier: analysis of temporal variations and model estimates of sources and radiative forcing

Characteristics of Black Carbon Aerosol during the Chinese Lunar Year and Weekdays in Xi’an, China

Similarities and differences of aerosol optical properties between southern and northern sides of the Himalayas

Contact Info

Product

Resources

About