Seasonal and elevational variations of black carbon and dust in snow and ice in the Solu-Khumbu, Nepal and estimated radiative forcings

Kaspari, Susan; Painter, T. H.; Gysel, M.; Skiles, M.; Schwikowski, Margit

doi:10.5194/acp-14-8089-2014

Cited by 165 publications

(162 citation statements)

References 72 publications

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“…Based on a 10-year record of mineral dust and BC concentrations, retrieved from an ice core at Mera Peak, Nepalese Himalaya, Ginot et al (2014) found that lightabsorbing particulates cause up to 26 % of the total annual surface melting. Another study performed at Mera Peak shows that mineral dust dominates absorption and may reduce the albedo of snow by up to 40 % (Kaspari et al, 2014). Investigations for the Colorado River basin, western US, show that the radiative forcing of mineral dust deposition may shorten the duration of snow cover by several weeks (Skiles et al, 2012) and also affects the timing and magnitude of runoff (Painter et al, 2010).…”

Section: J Gabbi Et Al: Impact Of Saharan Dust and Black Carbon On mentioning

confidence: 99%

“…Kaspari et al (2014) determined light absorption of mineral dust in snow and ice of a Himalayan glacier based on gravimetrically determined Fe concentrations. Accordingly, we used records of iron (Fe), provided by the ice core, to infer mineral dust concentrations.…”

Section: Mineral Dustmentioning

confidence: 99%

“…In order to model the effect of mineral dust on snow albedo, the mineral dust (i.e., Fe oxides) was converted to optically equivalent concentrations of light-absorbing carbon using mass absorption coefficients (MACs) of BC and Fe oxides of 6.8 and 0.56 m 2 g −1 , respectively Kaspari et al, 2014). The direct-beam albedo of the impurity-loaded snow is then obtained as α = α SSA + dα C .…”

Section: Albedo Modelmentioning

confidence: 99%

“…According to Shi et al (2011) the mass ratio of the mineral haematite to the minerals haematite plus goethite for Saharan dust is 0.42 on average. Based on the assumption that about 45-64 % of the total Fe is encompassed in lightabsorbing oxides , the mass of goethite and haematite is calculated following Kaspari et al (2014) and used as proxy for the absorption of mineral dust. Most of the dust peaks can be related to long-range transported crustal impurities, which account for about 70 % of the total deposited mineral dust (Wagenbach et al, 1996).…”

Section: Mineral Dustmentioning

confidence: 99%

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The impact of Saharan dust and black carbon on albedo and long-term mass balance of an Alpine glacier

Gabbi¹,

Huss

Bauder³

et al. 2015

The Cryosphere

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Abstract. Light-absorbing impurities in snow and ice control glacier melt as shortwave radiation represents the main component of the surface energy balance. Here, we investigate the long-term effect of snow impurities, i.e., mineral dust and black carbon (BC), on albedo and glacier mass balance. The analysis was performed over the period 1914-2014 for two sites on Claridenfirn, Swiss Alps, where an outstanding 100-year record of seasonal mass balance measurements is available. Information on atmospheric deposition of mineral dust and BC over the last century was retrieved from two firn/ice cores of high-alpine sites. A combined mass balance and snow/firn layer model was employed to assess the effects of melt and accumulation processes on the impurity concentration at the surface and thus on albedo and glacier mass balance. Compared to pure snow conditions, the presence of Saharan dust and BC lowered the mean annual albedo by 0.04-0.06 depending on the location on the glacier. Consequently, annual melt was increased by 15-19 %, and the mean annual mass balance was reduced by about 280-490 mm w.e. BC clearly dominated absorption which is about 3 times higher than that of mineral dust. The upper site has experienced mainly positive mass balances and impurity layers were continuously buried whereas at the lower site, surface albedo was more strongly influenced by re-exposure of dust and BC-enriched layers due to frequent years with negative mass balances.

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Section: J Gabbi Et Al: Impact Of Saharan Dust and Black Carbon On mentioning

confidence: 99%

Section: Mineral Dustmentioning

confidence: 99%

Section: Albedo Modelmentioning

confidence: 99%

Section: Mineral Dustmentioning

confidence: 99%

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The impact of Saharan dust and black carbon on albedo and long-term mass balance of an Alpine glacier

Gabbi¹,

Huss

Bauder³

et al. 2015

The Cryosphere

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“…During the cold and dry winter season, haze (heavily loaded with carbonaceous aerosols) builds up over South Asia, and exerts profound influences on regional radiative forcing Ramanathan and Carmichael, 2008), hydrologic cycles (Menon et al, 2002;Ramanathan et al, 2005), and likely Himalaya-Tibetan glacier melting that could be accelerated by the absorption of sunlight induced by BC in the air and deposited on the ice and snow surfaces Hansen and Nazarenko, 2004), although BC deposited in snow and glaciers at some locations may not significantly affect the energy balance Kaspari et al, 2014).…”

mentioning

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.

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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.

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Parameterizations for narrowband and broadband albedo of pure snow and snow containing mineral dust and black carbon

2015

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The reduction of snow spectral albedo by black carbon (BC) and mineral dust, both alone and in combination, is computed using radiative transfer modeling. Broadband albedo is shown for mass fractions covering the full range from pure snow to pure BC and pure dust, and for snow grain radii from 5 μm to 2500 μm, to cover the range of possible grain sizes on planetary surfaces. Parameterizations are developed for opaque homogeneous snowpacks for three broad bands used in general circulation models and several narrower bands. They are functions of snow grain radius and the mass fraction of BC and/or dust and are valid up to BC content of 10 ppm, needed for highly polluted snow. A change of solar zenith angle can be mimicked by changing grain radius. A given mass fraction of BC causes greater albedo reduction in coarse-grained snow; BC and grain radius can be combined into a single variable to compute the reduction of albedo relative to pure snow. The albedo reduction by BC is less if the snow contains dust, a common situation on mountain glaciers and in agricultural and grazing lands. Measured absorption spectra of mineral dust are critically reviewed as a basis for specifying dust properties for modeling. The effect of dust on snow albedo at visible wavelengths can be represented by an "equivalent BC" amount, scaled down by a factor of about 200. Dust has little effect on the near-IR albedo because the near-IR albedo of pure dust is similar to that of pure snow.

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Seasonal and elevational variations of black carbon and dust in snow and ice in the Solu-Khumbu, Nepal and estimated radiative forcings

Cited by 165 publications

References 72 publications

The impact of Saharan dust and black carbon on albedo and long-term mass balance of an Alpine glacier

The impact of Saharan dust and black carbon on albedo and long-term mass balance of an Alpine glacier

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

Parameterizations for narrowband and broadband albedo of pure snow and snow containing mineral dust and black carbon

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