Identification of trends and interannual variability of sulfate and black carbon in the Canadian High Arctic: 1981–2007

Gong, S. L.; Zhao, Tianliang; Sharma, Sangeeta; Toom-Sauntry, D.; Lavoué, D.; Zhang, X. B.; Leaitch, W. R.; Barrie, Leonard A.

doi:10.1029/2009jd012943

Cited by 93 publications

(100 citation statements)

References 47 publications

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“…Ground-based measurements of sulfate aerosol concentrations in March/April have decreased by 27-63 % between 1990 and 2003 across a range of Arctic sites, and appear to have leveled off (Quinn et al, 2007). This negative trend has been attributed to the decrease in anthropogenic emissions from Eurasia (Quinn et al, 2009;Gong et al, 2010); Hirdman et al, 2010). Recent modeling studies show that despite declining emissions, Europe and Russia continue to constitute the largest contributors of Arctic sulfate and black carbon (BC) aerosols at the surface (Shindell et al, 2008) due to their vicinity and favorable transport patterns to the Arctic (Stohl, 2006).…”

Section: Introductionmentioning

confidence: 99%

“…Among the factors that affect aerosol mass concentration variability on interannual timescales, transport and emissions have been found to play the greatest role and account for 75 % of the observed variability at the surface in the High Canadian Arctic (Gong et al, 2010). Biomass burning emissions display a strong interannual variability, especially in boreal environments (van der Werf et al, 2006).…”

Section: Interannual Variabilitymentioning

confidence: 99%

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Spatial and seasonal distribution of Arctic aerosols observed by the CALIOP satellite instrument (2006–2012)

et al. 2013

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We use retrievals of aerosol extinction from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) onboard the CALIPSO satellite to examine the vertical, horizontal and temporal variability of tropospheric Arctic aerosols during the period 2006–2012. We develop an empirical method that takes into account the difference in sensitivity between daytime and nighttime retrievals over the Arctic. Comparisons of the retrieved aerosol extinction to in situ measurements at Barrow (Alaska) and Alert (Canada) show that CALIOP reproduces the observed seasonal cycle and magnitude of surface aerosols to within 25 %. In the free troposphere, we find that daytime CALIOP retrievals will only detect the strongest aerosol haze events, as demonstrated by a comparison to aircraft measurements obtained during NASA's ARCTAS mission during April 2008. This leads to a systematic underestimate of the column aerosol optical depth by a factor of 2–10. However, when the CALIOP sensitivity threshold is applied to aircraft observations, we find that CALIOP reproduces in situ observations to within 20% and captures the vertical profile of extinction over the Alaskan Arctic. Comparisons with the ground-based high spectral resolution lidar (HSRL) at Eureka, Canada, show that CALIOP and HSRL capture the evolution of the aerosol backscatter vertical distribution from winter to spring, but a quantitative comparison is inconclusive as the retrieved HSRL backscatter appears to overestimate in situ observations by a factor of 2 at all altitudes. In the High Arctic (>70° N) near the surface (<2 km), CALIOP aerosol extinctions reach a maximum in December–March (10–20 Mm⁻¹), followed by a sharp decline and a minimum in May–September (1–4 Mm⁻¹), thus providing the first pan-Arctic view of Arctic haze seasonality. The European and Asian Arctic sectors display the highest wintertime extinctions, while the Atlantic sector is the cleanest. Over the Low Arctic (60–70° N) near the surface, CALIOP extinctions reach a maximum over land in summer due to boreal forest fires. During summer, we find that smoke aerosols reach higher altitudes (up to 4 km) over eastern Siberia and North America than over northern Eurasia, where they remain mostly confined below 2 km. In the free troposphere, the extinction maximum over the Arctic occurs in March–April at 2–5 km altitude and April–May at 5–8 km. This is consistent with transport from the midlatitudes associated with the annual maximum in cyclonic activity and blocking patterns in the Northern Hemisphere. A strong gradient in aerosol extinction is observed between 60° N and 70° N in the summer. This is likely due to efficient stratocumulus wet scavenging at high latitudes combined with the poleward retreat of the polar front. Interannual variability in the middle and upper troposphere is associated with biomass burning events (high extinctions observed by CALIOP in spring 2008 and summer 2010) and volcanic eruptions (Kasatochi in August 2008 and Sarychev in June 2009). CALIOP displays below-a...

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Section: Introductionmentioning

confidence: 99%

Section: Interannual Variabilitymentioning

confidence: 99%

Spatial and seasonal distribution of Arctic aerosols observed by the CALIOP satellite instrument (2006–2012)

et al. 2013

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“…Snow on the Greenland Ice Sheet is the cleanest snow of the Arctic, and these values represent the free tropospheric BC content at an elevation of ∼2600 m, so it is of interest to examine evidence from lower-elevation sites where only seasonal snow, rather than ice cores, is available. BC in the near-surface atmosphere has been monitored continuously since 1989 at Alert on Ellesmere Island (82.4 • N, 62.3 • W, 210 m) (Gong et al, 2010), and at Barrow, Alaska (Sharma et al, 2006), and since 1998 at the Zeppelin station above Ny-Ålesund (79 • N, 12 • E, 474 m) (Eleftheriadis et al, 2009;Forsström et al, 2009). All three locations document the seasonal cycle with BC concentrations peaking in winter, and all three show a multi-year decline of the wintertime peak.…”

Section: Has the Arctic Snow Become Cleaner Since 1984?mentioning

confidence: 99%

“…In the Arctic Ocean, some of the sea ice is heavily laden with sediment, picked up by ice freezing to the sea floor on the shallow Siberian shelf, particularly in the Kara, Laptev, and East Siberian seas (Frey et al, 2001;Ivanov, 2005;Eicken et al, 2003Eicken et al, , 2005. In subsequent years the sediment rises as the upper ice surface melts and new ice freezes to the base.…”

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Light-absorbing impurities in Arctic snow

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et al. 2010

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“…The early observations were attributed to fossil fuel combustion in northern Europe and Russia, based on air flow back-trajectories and correlations with trace metal tracers (Shaw, 1982;Djupstrom et al, 1993). BC concentrations in the Arctic decreased from the 1980s to 2000, followed by a slight increase in the past decade (Sharma et al, 2006;Eleftheriadis et al, 2009;Gong et al, 2010;Hirdman et al, 2010). Recent measurements of BC in Arctic snow show a strong association with biomass burning based on tracer correlations and optical properties (Hegg et al, 2009;Doherty et al, 2010;Hegg et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Sources of carbonaceous aerosols and deposited black carbon in the Arctic in winter-spring: implications for radiative forcing

et al. 2011

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Abstract. We use a global chemical transport model (GEOSChem CTM) to interpret observations of black carbon (BC) and organic aerosol (OA) from the NASA ARCTAS aircraft campaign over the North American Arctic in April 2008, as well as longer-term records in surface air and in snow (2007)(2008)(2009). BC emission inventories for North America, Europe, and Asia in the model are tested by comparison with surface air observations over these source regions. Russian open fires were the dominant source of OA in the Arctic troposphere during ARCTAS but we find that BC was of prevailingly anthropogenic (fossil fuel and biofuel) origin, particularly in surface air. This source attribution is confirmed by correlation of BC and OA with acetonitrile and sulfate in the model and in the observations. Asian emissions are the main anthropogenic source of BC in the free troposphere but European, Russian and North American sources are also important in surface air. Russian anthropogenic emissions appear to dominate the source of BC in Arctic surface air in winter. Model simulations for 2007-2009 (to account for interannual variability of fires) show much higher BC snow content in the Eurasian than the North American Arctic, consistent with the limited observations. We find that anthropogenic sourcesCorrespondence to: Q. Wang (wang2@fas.harvard.edu) contribute 90 % of BC deposited to Arctic snow in JanuaryMarch and 60 % in April-May 2007-2009. The mean decrease in Arctic snow albedo from BC deposition is estimated to be 0.6 % in spring, resulting in a regional surface radiative forcing consistent with previous estimates.

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Identification of trends and interannual variability of sulfate and black carbon in the Canadian High Arctic: 1981–2007

Cited by 93 publications

References 47 publications

Spatial and seasonal distribution of Arctic aerosols observed by the CALIOP satellite instrument (2006–2012)

Spatial and seasonal distribution of Arctic aerosols observed by the CALIOP satellite instrument (2006–2012)

Light-absorbing impurities in Arctic snow

Sources of carbonaceous aerosols and deposited black carbon in the Arctic in winter-spring: implications for radiative forcing

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