Optimized method for black carbon analysis in ice and snow using the Single Particle Soot Photometer

Wendl, I. A.; Menking, J. A.; Farber, Robert J.; Gysel, M.; Kaspari, Susan; Laborde, M.; Schwikowski, Margit

doi:10.5194/amtd-7-3075-2014

Cited by 34 publications

(69 citation statements)

References 27 publications

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“…The nebulization efficiency was 20 % or less for particles greater than 700 nm relative to particles in the 200-500 nm size range. Subsequent research at Central Washington University confirmed the results of Schwarz for the Cetac, while Wendl et al (2014) found that for the Cetac, nebulization efficiency was greatest in the 300-400 nm size range, with decreased efficiency for smaller and larger particle sizes. Additionally, Schwarz et al (2013) report larger mass size distributions of BC in snow than BC in the atmosphere, with the mass of BC cores larger than 600 nm accounting for 17 % or more of the BC mass based on snow samples in Colorado.…”

Section: Bc Analytical Methodssupporting

confidence: 58%

“…Aquadag standards that measured 7, 5, and 2 µg L −1 BC directly after the standards were created decreased to 4, 1.8, and 0.3 µg L −1 BC, indicating that measured concentrations after 18 days were 57, 36, and 15 % of the initially measured concentrations, respectively. An environmental snow sample that initially was measured as having a concentration of 2.4 µg L −1 BC decreased to 0.6 µg L −1 after 18 days, or 25 % of the initially measured concentration (Wendl et al, 2014). These results suggest that apparent BC losses are proportionally greater in low concentration samples relative to higher concentration samples.…”

Section: Bc Analytical Methodssupporting

confidence: 53%

“…Apparent BC losses due to changes to the sample during storage. Repeated measurements on aqueous samples stored at ambient temperature demonstrate a reduction in measured BC concentrations over time (Wendl et al, 2014). Re-measuring Aquadag standards and environmental samples stored at room temperature in polypropylene vials over an 18 day period indicated that BC losses are dependent on sample concentration.…”

Section: Bc Analytical Methodsmentioning

confidence: 99%

“…This standard correction does not fully address the size dependent nebulization nor likely differences in the mass-size distributions of Aquadag and the snow samples. We also note that prior studies using the SP2 to measure BC concentrations in liquid samples have used other BC materials as a calibration standard, with other standards resulting in a higher corrected BC concentration than Aquadag (Wendl et al, 2014).…”

Section: Bc Analytical Methodsmentioning

confidence: 99%

“…Additional advantages of the SP2 is that smaller sample volumes are required than other BC analytical methods, and the method does not use filters that can have filtration efficiency issues. Further details on the SP2 calibration and configuration are provided by Wendl et al (2014) and in the auxiliary materials of Kaspari et al (2011). The samples were sonicated for 15 minutes just prior to analysis.…”

Section: Bc Analytical Methodsmentioning

confidence: 99%

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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

et al. 2014

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Abstract. Black carbon (BC) and dust deposited on snow and glacier surfaces can reduce the surface albedo, accelerate snow and ice melt, and trigger albedo feedback. Assessing BC and dust concentrations in snow and ice in the Himalaya is of interest because this region borders large BC and dust sources, and seasonal snow and glacier ice in this region are an important source of water resources. Snow and ice samples were collected from crevasse profiles and snow pits at elevations between 5400 and 6400 m a.s.l. from Mera glacier located in the Solu-Khumbu region of Nepal during spring and fall 2009, providing the first observational data of BC concentrations in snow and ice from the southern slope of the Himalaya. The samples were measured for Fe concentrations (used as a dust proxy) via ICP-MS, total impurity content gravimetrically, and BC concentrations using a Single Particle Soot Photometer (SP2). Measured BC concentrations underestimate actual BC concentrations due to changes to the sample during storage and loss of BC particles in the ultrasonic nebulizer; thus, we correct for the underestimated BC mass. BC and Fe concentrations are substantially higher at elevations < 6000 m due to post-depositional processes including melt and sublimation and greater loading in the lower troposphere. Because the largest areal extent of snow and ice resides at elevations < 6000 m, the higher BC and dust concentrations at these elevations can reduce the snow and glacier albedo over large areas, accelerating melt, affecting glacier mass balance and water resources, and contributing to a positive climate forcing. Radiative transfer modeling constrained by measurements at 5400 m at Mera La indicates that BC concentrations in the winter-spring snow/ice horizons are sufficient to reduce albedo by 6-10 % relative to clean snow, corresponding to localized instantaneous radiative forcings of 75-120 W m −2 . The other bulk impurity concentrations, when treated separately as dust, reduce albedo by 40-42 % relative to clean snow and give localized instantaneous radiative forcings of 488 to 525 W m −2 . Adding the BC absorption to the other impurities results in additional radiative forcings of 3 W m −2 . The BC and Fe concentrations were used to further examine relative absorption of BC and dust. When dust concentrations are high, dust dominates absorption, snow albedo reduction, and radiative forcing, and the impact of BC may be negligible, confirming the radiative transfer modeling. When impurity concentrations are low, the absorption by BC and dust may be comparable; however, due to the low impurity concentrations, albedo reductions are small. While these results suggest that the snow albedo and radiative forcing effect of dust is considerably greater than BC, there are several sources of uncertainty. Further observational studies are needed to address the contribution of BC, dust, and colored organics to albedo reductions and snow and ice melt, and to characterize the time variation of radiative forcing.

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Section: Bc Analytical Methodssupporting

confidence: 58%

Section: Bc Analytical Methodssupporting

confidence: 53%

Section: Bc Analytical Methodsmentioning

confidence: 99%

Section: Bc Analytical Methodsmentioning

confidence: 99%

Section: Bc Analytical Methodsmentioning

confidence: 99%

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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

et al. 2014

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Accelerated glacier melt on Snow Dome, Mount Olympus, Washington, USA, due to deposition of black carbon and mineral dust from wildfire

Kaspari

Skiles²,

Delaney

et al. 2015

JGR Atmospheres

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Assessing the potential for black carbon (BC) and dust deposition to reduce albedo and accelerate glacier melt is of interest in Washington because snow and glacier melt are an important source of water resources, and glaciers are retreating. In August 2012 on Snow Dome, Mount Olympus, Washington, we measured snow surface spectral albedo and collected surface snow samples and a 7 m ice core. The snow and ice samples were analyzed for iron (Fe, used as a dust proxy) via inductively coupled plasma sector field mass spectrometry, total impurity content gravimetrically, BC using a single-particle soot photometer (SP2), and charcoal through microscopy. In the 2012 summer surface snow, BC (54 ± 50 μg/L), Fe (367±236 μg/L) and gravimetric impurity (35 ± 18 mg/L) concentrations were spatially variable, and measured broadband albedo varied between 0.67-0.74. BC and dust concentrations in the ice core 2011 summer horizon were a magnitude higher (BC = 3120 μg/L, Fe = 22000 μg/L, and gravimetric impurity = 1870 mg/L), corresponding to a modeled broadband albedo of 0.45 based on the measured BC and gravimetric impurity concentrations. The Big Hump forest fire is the likely source for the higher concentrations. Modeling constrained by measurements indicates that the all-sky 12 h daily mean radiative forcings in summer 2012 and 2011 range between 37-53 W m À2 and 112-149 W m À2 , respectively, with the greater forcings in 2011 corresponding to a 29-38 mm/d enhancement in snowmelt. The timing of the forest fire impurity deposition is coincident with an increase in observed discharge in the Hoh River, highlighting the potential for BC and dust deposition on glaciers from forest fires to accelerate melt.

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Black carbon concentrations in snow at Tronsen Meadow in Central Washington from 2012 to 2013: Temporal and spatial variations and the role of local forest fire activity

2015

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Characterizing black carbon (BC) concentrations in the seasonal snowpack is of interest because BC deposition on snow can reduce albedo and accelerate melt. In Washington State, USA snowmelt from the seasonal snowpack provides an important source of water resources, but minimal work has been done characterizing BC concentrations in snow in this region. BC concentrations in snow were monitored over two winters (2012 and 2013) at Tronsen Meadow, located near Blewett Pass in the eastern Cascade Mountains in Central Washington, to characterize spatial and temporal variations in BC concentrations, and the processes affecting BC concentrations in the snowpack. BC concentrations were measured using a Single Particle Soot Photometer. Snowpit BC concentrations at spatial scales ranging from centimeter to 100 m scales were fairly homogenous during the accumulation season, with greater spatial variability during the melt season due to variable melt patterns. BC concentrations in snow increased in late winter‐spring due to an increase in atmospheric BC concentrations and trapping of BC on the snow surface during melt. However, during a period of intense melt in 2013 BC concentrations decreased, likely caused by meltwater scavenging. In summer 2012 the Table Mountain forest fire burned adjacent to the study site, and BC concentrations in the snowpack in 2013 were far higher than in previous years, with charred trees postfire the likely source of the elevated BC.

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Optimized method for black carbon analysis in ice and snow using the Single Particle Soot Photometer

Cited by 34 publications

References 27 publications

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

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

Accelerated glacier melt on Snow Dome, Mount Olympus, Washington, USA, due to deposition of black carbon and mineral dust from wildfire

Black carbon concentrations in snow at Tronsen Meadow in Central Washington from 2012 to 2013: Temporal and spatial variations and the role of local forest fire activity

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