Seasonality of global and Arctic black carbon processes in the Arctic Monitoring and Assessment Programme models

Mahmood, Rashed; Salzen, Knut von; Flanner, M.; Sand, Maria; Langner, Joakim; Wang, Hailong; Huang, Lin

doi:10.1002/2016jd024849

Cited by 54 publications

(66 citation statements)

References 68 publications

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“…It is the only model that matches the high measured sulfate values at Alert and Station Nord in spring. The reason why CanAM4.2 captures the spring peak better might be that this model has a less efficient removal through wet deposition under stratiform conditions compared to the other models (Mahmood et al, 2015). At Pallas, the lowest-latitude station in this comparison, most models severely underestimate sulfate throughout the year (Fig.…”

Section: Observed and Simulated Bc And Sulfate Seasonality At Arctic mentioning

confidence: 95%

Current model capabilities for simulating black carbon and sulfate concentrations in the Arctic atmosphere: a multi-model evaluation using a comprehensive measurement data set

et al. 2015

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International audienceThe concentrations of sulfate, black carbon (BC) and other aerosols in the Arctic are characterized by high values in late winter and spring (so-called Arctic Haze) and low values in summer. Models have long been struggling to capture this seasonality and especially the high concentrations associated with Arctic Haze. In this study, we evaluate sulfate and BC concentrations from eleven different models driven with the same emission inventory against a comprehensive pan-Arctic measurement data set over a time period of two years (2008–2009). The set of models consisted of one Lagrangian particle dispersion model, four chemistry-transport models (CTMs), one atmospheric chemistry-weather forecast model and five chemistry-climate models (CCMs), of which two were nudged to meteorological analyses and three were running freely. The measurement data set consisted of surface measurements of equivalent BC (eBC) from five stations (Alert, Barrow, Pallas, Tiksi and Zeppelin), elemental carbon (EC) from Station Nord and Alert and aircraft measurements of refractory BC (rBC) from six different campaigns. We find that the models generally captured the measured eBC/rBC and sulfate concentrations quite well, compared to past comparisons. However, the aerosol seasonality at the surface is still too weak in most models. Concentrations of eBC and sulfate averaged over three surface sites are underestimated in winter/spring in all but one model (model means for January-March underestimated by 59 and 37% for BC and sulfate, respectively), whereas concentrations in summer are overestimated in the model mean (by 88 and 44% for July–September), but with over- as well as underestimates present in individual models. The most pronounced eBC underestimates, not included in the above multi-site average, are found for the station Tiksi in Siberia where the measured annual mean eBC concentration is three times higher than the average annual mean for all other stations. This suggests an underestimate of BC sources in Russia in the emission inventory used. Based on the campaign data, biomass burning was identified as another cause of the modelling problems. For sulfate, very large differences were found in the model ensemble, with an apparent anti-correlation between modeled surface concentrations and total atmospheric columns. There is a strong correlation between observed sulfate and eBC concentrations with consistent sulfate/eBC slopes found for all Arctic stations, indicating that the sources contributing to sulfate and BC are similar throughout the Arctic and that the aerosols are internally mixed and undergo similar removal. However, only three models reproduced this finding, whereas sulfate and BC are weakly correlated in the other models. Overall, no class of models (e.g., CTMs, CCMs) performed better than the others and differences are independent of model resolution

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Section: Observed and Simulated Bc And Sulfate Seasonality At Arctic mentioning

confidence: 95%

Current model capabilities for simulating black carbon and sulfate concentrations in the Arctic atmosphere: a multi-model evaluation using a comprehensive measurement data set

et al. 2015

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“…RAPID ADJUSTMENTS CAUSE WEAK BC RESPONSE 11,462 of ambient BC absorption (Boucher et al, 2016;Gustafsson & Ramanathan, 2016;Peng et al, 2016) as well as in factors such as dry and wet removal efficiency (Mahmood et al, 2016), and the contribution from brown carbon is still uncertain (Liu et al, 2014). BC also influences climate through indirect effects (microphysical influence of BC aerosols on cloud droplets, Twomey, 1974) and semidirect effects (BC absorption influences the short-wave heating rate, influencing the vertical temperature profile and/or causing evaporation of cloud droplets, Ackerman et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Rapid Adjustments Cause Weak Surface Temperature Response to Increased Black Carbon Concentrations

et al. 2017

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We investigate the climate response to increased concentrations of black carbon (BC), as part of the Precipitation Driver Response Model Intercomparison Project (PDRMIP). A tenfold increase in BC is simulated by nine global coupled‐climate models, producing a model median effective radiative forcing of 0.82 (ranging from 0.41 to 2.91) W m−2, and a warming of 0.67 (0.16 to 1.66) K globally and 1.24 (0.26 to 4.31) K in the Arctic. A strong positive instantaneous radiative forcing (median of 2.10 W m−2 based on five of the models) is countered by negative rapid adjustments (−0.64 W m−2 for the same five models), which dampen the total surface temperature signal. Unlike other drivers of climate change, the response of temperature and cloud profiles to the BC forcing is dominated by rapid adjustments. Low‐level cloud amounts increase for all models, while higher‐level clouds are diminished. The rapid temperature response is particularly strong above 400 hPa, where increased atmospheric stabilization and reduced cloud cover contrast the response pattern of the other drivers. In conclusion, we find that this substantial increase in BC concentrations does have considerable impacts on important aspects of the climate system. However, some of these effects tend to offset one another, leaving a relatively small median global warming of 0.47 K per W m−2—about 20% lower than the response to a doubling of CO2. Translating the tenfold increase in BC to the present‐day impact of anthropogenic BC (given the emissions used in this work) would leave a warming of merely 0.07 K.

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“…9) and its deposition to the Arctic was smaller than EUR-AN and RUS-AN (Table 1). The average lifetime of 21.3 days in the Arctic was close to the 20.0-day the multi-model mean in the AMAP (Arctic Monitoring and Assessment Programme) models (Mahmood et al, 2016). Table 2 summarizes the relative contributions from individual sources to the annual mean BC concentrations, burden, and deposition over the Arctic (66-90 • N).…”

Section: Source Contributions To the Annual Budget Of Bc In The Arcticmentioning

confidence: 99%

“…Although a recent model intercomparison study indicated that the model performance of the BC simulations in the Arctic has improved, the seasonal amplitude at the surface was too weak and the BC concentration levels at the surface sites were still underestimated in the Arctic haze season in many state-of-the-science models (Eckhardt et al, 2015). Mahmood et al (2016) pointed out that convective wet deposition outside the Arctic influenced vertical distribution and seasonal variations in BC in the Arctic by analyzing the same models used by Eckhardt et al (2015). These difficulties in the model simulation of Arctic BC are key uncertainties in calculating the source contributions from important emission sources in the northern midlatitudes and high latitudes.…”

Section: Introductionmentioning

confidence: 99%

Tagged tracer simulations of black carbon in the Arctic: transport, source contributions, and budget

et al. 2017

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Abstract. We implemented a tagged tracer method of black carbon (BC) into a global chemistry transport model, GEOSChem, examined the pathways and efficiency of long-range transport from a variety of anthropogenic and biomass burning emission sources to the Arctic, and quantified the source contributions of individual emissions. Firstly, we evaluated the simulated BC by comparing it with observations at the Arctic sites and examined the sensitivity of an aging parameterization and wet scavenging rate by ice clouds. For tagging BC, we added BC tracers distinguished by source types (anthropogenic and biomass burning) and regions; the global domain was divided into 16 and 27 regions for anthropogenic and biomass burning emissions, respectively. Our simulations showed that BC emitted from Europe and Russia was transported to the Arctic mainly in the lower troposphere during winter and spring. In particular, BC transported from Russia was widely spread over the Arctic in winter and spring, leading to a dominant contribution of 62 % to the Arctic BC near the surface as the annual mean. In contrast, BC emitted from East Asia was found to be transported in the middle troposphere into the Arctic mainly over the Sea of Okhotsk and eastern Siberia during winter and spring. We identified an important "window" area, which allowed a strong incoming of East Asian BC to the Arctic (130-180 • E and 3-8 km of altitude at 66 • N). The model demonstrated that the contribution from East Asia to the Arctic had a maximum at about 5 km of altitude due to uplifting during long-range transport in early spring. The efficiency of BC transport from East Asia to the Arctic was lower than that from other large source regions such as Europe, Russia, and North America. However, the East Asian contribution was the most important for BC in the middle troposphere (41 %) and the BC burden over the Arctic (27 %) because of the large emissions from this region. These results suggested that the main sources of Arctic BC differed with altitude. The contribution of all the anthropogenic sources to Arctic BC concentrations near the surface was dominant (90 %) on an annual basis. The contributions of biomass burning in boreal regions (Siberia, Alaska, and Canada) to the annual total BC deposition onto the Arctic were estimated to be 12-15 %, which became the maximum during summer.

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Seasonality of global and Arctic black carbon processes in the Arctic Monitoring and Assessment Programme models

Cited by 54 publications

References 68 publications

Current model capabilities for simulating black carbon and sulfate concentrations in the Arctic atmosphere: a multi-model evaluation using a comprehensive measurement data set

Current model capabilities for simulating black carbon and sulfate concentrations in the Arctic atmosphere: a multi-model evaluation using a comprehensive measurement data set

Rapid Adjustments Cause Weak Surface Temperature Response to Increased Black Carbon Concentrations

Tagged tracer simulations of black carbon in the Arctic: transport, source contributions, and budget

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