Soot in the arctic snowpack: a cause for perturbations in radiative transfer

Clarke, A. D.; Noone, Kevin M.

doi:10.1016/j.atmosenv.2007.10.059

Cited by 179 publications

(241 citation statements)

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“…As with other common light-absorbing particles in the atmosphere (Clarke and Noone 1985;Warren and Clarke 1990), dust trapped in snow or glacier ice will not only decrease the sensitivity of the instrument ) but also bias the WIOC/EC split point during the analysis as demonstrated in this study. This bias is especially prevalent in samples containing obvious dust particles because the dust content may be several orders of magnitude higher than EC, while the absorption coefficient is 2 or 3 times of magnitude smaller (Warren and Clarke 1990;Hansen et al 1993).…”

Section: Introductionmentioning

confidence: 87%

The Influence of Dust on Quantitative Measurements of Black Carbon in Ice and Snow when Using a Thermal Optical Method

Wang

Zhao

et al. 2012

Aerosol Science and Technology

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Accurate measurements of black carbon concentrations in snow and ice are essential to quantify its impact on glacial melting and sequential climate forcing via snow albedo. However, snow and ice contain dust that may severely bias the precision of the elemental carbon (EC) and organic carbon (OC) measurements of filters with a thermal/optical method. To evaluate the effects of dust on black carbon analysis and to optimize filtration methods, meltwater from ice core and surface snow samples with variable dust content were filtered with different methods, including filtration of the entire material (including settling) and supernatant liquid, mechanical stirring and sonication, as well as utilization of single and double quartz filters. In this research, it is shown that dust can induce an extra decrease in optical reflectance during the 250• C heating stage in the thermal/optical method and an improper OC and EC split. To address this problem, a correction procedure was suggested and used to revise the OC and EC results. The OC, EC, and TC concentration variations from different filtration methods along the ice core depth and along surface snow elevation were illustrated. These results indicate that black carbon and dust generally mix as agglomerates. The agglomerate structure will contribute to the underestimation of EC and OC in the measurement. However, carbonaceous matter can be efficiently detached from dust particles by ultrasonic agitation of the meltwater samples, which significantly improves carbon volatilization during the thermal/optical analysis.

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Section: Introductionmentioning

confidence: 87%

The Influence of Dust on Quantitative Measurements of Black Carbon in Ice and Snow when Using a Thermal Optical Method

Wang

Zhao

et al. 2012

Aerosol Science and Technology

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“…In addition, once deposited to snow or ice, BC and OC absorb radiation within the snowpack, and cause an earlier snow disappearance or decrease the snow mass, inducing a positive forcing at the surface, through decreased albedo (e.g. Warren and Wiscombe, 1980;Clarke and Noone, 1985;Jacobson, 2004;Hadley and Kirchstetter, 2012). Overall, Shindell and Faluvegi (2009) and Shindell (2012) pointed out that the temperature response to a radiative forcing is not necessarily correlated with the location of this radiative forcing.…”

Section: Introductionmentioning

confidence: 99%

Boreal and temperate snow cover variations induced by black carbon emissions in the middle of the 21st century

et al. 2013

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Abstract. We used a coupled climate-chemistry model to quantify the impacts of aerosols on snow cover north of 30 • N both for the present-day and for the middle of the 21st century. Black carbon (BC) deposition over continents induces a reduction in the mean number of days with snow at the surface (MNDWS) that ranges from 0 to 10 days over large areas of Eurasia and Northern America for the presentday relative to the pre-industrial period. This is mainly due to BC deposition during the spring, a period of the year when the remaining of snow accumulated during the winter is exposed to both strong solar radiation and a large amount of aerosol deposition induced themselves by a high level of transport of particles from polluted areas. North of 30 • N, this deposition flux represents 222 Gg BC month −1 on average from April to June in our simulation. A large reduction in BC emissions is expected in the future in all of the Representative Concentration Pathway (RCP) scenarios. In particular, considering the RCP8.5 in our simulation leads to a decrease in the spring BC deposition down to 110 Gg month −1 in the 2050s. However, despite the reduction of the aerosol impact on snow, the MNDWS is strongly reduced by 2050, with a decrease ranging from 10 to 100 days from presentday values over large parts of the Northern Hemisphere. This reduction is essentially due to temperature increase, which is quite strong in the RCP8.5 scenario in the absence of climate mitigation policies. Moreover, the projected sea-ice retreat in the next decades will open new routes for shipping in the Arctic. However, a large increase in shipping emissions in the Arctic by the mid-21st century does not lead to significant changes of BC deposition over snow-covered areas in our simulation. Therefore, the MNDWS is clearly not affected through snow darkening effects associated with these Arctic ship emissions. In an experiment without nudging toward atmospheric reanalyses, we simulated however some changes of the MNDWS considering such aerosol ship emissions. These changes are generally not statistically significant in boreal continents, except in Quebec and in the West Siberian plains, where they range between −5 and −10 days. They are induced both by radiative forcings of the aerosols when they are in the snow and in the atmosphere, and by all the atmospheric feedbacks. These experiments do not take into account the feedbacks induced by the interactions between ocean and atmosphere as they were conducted with prescribed sea surface temperatures. Climate change by the mid-21st century could also cause biomass burning activity (forest fires) to become more intense and occur earlier in the season. In an idealised scenario in which forest fires are 50 % stronger and occur 2 weeks earlier and later than at present, we simulated an increase in spring BC deposition of 21 Gg BC month −1 over continents located north of 30 • N. This BC deposition does not impact directly the snow cover through snow darkening effects. However, in an experiment considering ...

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“…The radiation impact of this aerosol is still poorly understood. Moreover, the Arctic environment is very vulnerable during that season, as aerosol deposition on snow or ice covered surfaces reduces the albedo and favors an earlier onset of the melting season (Flanner et al, 2007;Clarke and Noone, 2007;Stroeve et al, 2007). The direct forcing of aerosol depends, among other factors, on its soot content (Stone et al, 2008;Ramanathan and Carmichael, 2008) and surface albedo.…”

Section: Introductionmentioning

confidence: 99%

Springtime Arctic aerosol: Smoke versus haze, a case study for March 2008

Stock¹,

Ritter²,

Herber³

et al. 2012

Atmospheric Environment

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a b s t r a c tDuring March 2008 photometer observations of Arctic aerosol were performed both at a Russian ice-floe drifting station (NP-35) at the central Arctic ocean (56.7e42.0 E, 85.5e84.2 N) and at Ny-Ålesund, Spitsbergen (78.9 N, 11.9 E). Next to a persistent increase of AOD over NP-35, two pronounced aerosol events have been recorded there, one originating from early season forest fires close to the city of Khabarovsk ("Arctic Smoke"), the other one showed trajectories from central Russia and resembled more the classical Arctic Haze. The latter event has also been recorded two days later over Ny-Ålesund, both in photometer and lidar. From these remote sensing instruments volume distribution functions are derived and discussed. Only subtle differences between the smoke and the haze event have been found in terms of particle microphysics. Different trajectory analysis, driven by NCEP and ECMWF have been performed and compared. For the data set presented here the meteorological field, due to sparseness of data in the central Arctic, mainly limits the precision of the air trajectories.

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Soot in the arctic snowpack: a cause for perturbations in radiative transfer

Cited by 179 publications

References 0 publications

The Influence of Dust on Quantitative Measurements of Black Carbon in Ice and Snow when Using a Thermal Optical Method

The Influence of Dust on Quantitative Measurements of Black Carbon in Ice and Snow when Using a Thermal Optical Method

Boreal and temperate snow cover variations induced by black carbon emissions in the middle of the 21st century

Springtime Arctic aerosol: Smoke versus haze, a case study for March 2008

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