The importance of the representation of air pollution emissions for the modeled distribution and radiative effects of black carbon in the Arctic
The importance of the representation of air pollution emissions for the modeled distribution and radiative effects of black carbon in the Arctic
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DOI：
10.5194/acp-19-11159-2019
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发表时间：
2019-02
影响因子：
6.3
通讯作者：
J. Schacht;B. Heinold;J. Quaas;J. Backman;R. Cherian;A. Ehrlich;A. Herber;W. Huang;Y. Kondo;A. Massling;P. Sinha;B. Weinzierl;M. Zanatta;I. Tegen
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文献类型：
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作者：
J. Schacht;B. Heinold;J. Quaas;J. Backman;R. Cherian;A. Ehrlich;A. Herber;W. Huang;Y. Kondo;A. Massling;P. Sinha;B. Weinzierl;M. Zanatta;I. Tegen
抽象。气溶胶粒子可以通过直接和间接的辐射效应对北极放大（AA）作出贡献。具体来说，大气中的黑碳（BC），当沉积在雪和海冰上时，在极地日期间对大气层顶（TOA）辐射平衡具有积极的变暖效应。然而，目前的气候模型仍在努力重现北极气溶胶条件。我们提出了一个评估研究与全球气溶胶气候模式ECHAM6.3-HAM2.3检查排放相关的不确定性的BC分布和BC的直接辐射效应。模型结果与2005-2017年期间最新的地面和空中气溶胶观测结果进行了全面比较，重点是BC。测试了四种不同的空气污染排放设置。模拟结果与观测到的北极近地表BC的数量和时间变化基本吻合。使用实际的每日而不是固定的生物质燃烧排放量是至关重要的再现个别污染事件，但只有一个小的影响BC的季节性周期。与通常使用的2000年固定人为排放量相比，一份包含瞬时空气污染排放量的最新清单导致当地的年度BC负担高出30%。这导致北极地区（北纬60-90度）大气顶部的BC年平均全天空净直接辐射效应高于0.1 W m−2，在北冰洋东部的局部地区超过0.2 W m−2。我们估计，北极地区的BC导致北极地区平均每年净增益为0.5 W m−2，但由于大气BC的直接辐射效应加上雪中BC减少的影响，局部增益高达0.8 W m−2。远距离传输被认为是ECHAM6.3-HAM2.3的主要不确定性来源之一，导致500 hPa以上大气层BC的高估，特别是在夏季。这与至少在一个已确定的案例中对除湿的错误陈述有关，这是在ARCTAS（从飞机和卫星上对对流层组成的北极研究）夏季飞机活动期间观察到的。总的来说，目前的模型版本已显着改善，因为以前的相互比较研究，现在表现得更好的多模式平均在气溶胶观测和模型之间的比较（AEROCOM）的倡议方面的空间和时间分布的北极BC。
Abstract. Aerosol particles can contribute to the Arctic amplification (AA) by direct and indirect radiative effects. Specifically, black carbon (BC) in the atmosphere, and when deposited on snow and sea ice, has a positive warming effect on the top-of-atmosphere (TOA) radiation balance during the polar day. Current climate models, however, are still struggling to reproduce Arctic aerosol conditions. We present an evaluation study with the global aerosol-climate model ECHAM6.3-HAM2.3 to examine emission-related uncertainties in the BC distribution and the direct radiative effect of BC. The model results are comprehensively compared against the latest ground and airborne aerosol observations for the period 2005–2017, with a focus on BC. Four different setups of air pollution emissions are tested. The simulations in general match well with the observed amount and temporal variability in near-surface BC in the Arctic. Using actual daily instead of fixed biomass burning emissions is crucial for reproducing individual pollution events but has only a small influence on the seasonal cycle of BC. Compared with commonly used fixed anthropogenic emissions for the year 2000, an up-to-date inventory with transient air pollution emissions results in up to a 30 % higher annual BC burden locally. This causes a higher annual mean all-sky net direct radiative effect of BC of over 0.1 W m−2 at the top of the atmosphere over the Arctic region (60–90∘ N), being locally more than 0.2 W m−2 over the eastern Arctic Ocean. We estimate BC in the Arctic as leading to an annual net gain of 0.5 W m−2 averaged over the Arctic region but to a local gain of up to 0.8 W m−2 by the direct radiative effect of atmospheric BC plus the effect by the BC-in-snow albedo reduction. Long-range transport is identified as one of the main sources of uncertainties for ECHAM6.3-HAM2.3, leading to an overestimation of BC in atmospheric layers above 500 hPa, especially in summer. This is related to a misrepresentation in wet removal in one identified case at least, which was observed during the ARCTAS (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites) summer aircraft campaign. Overall, the current model version has significantly improved since previous intercomparison studies and now performs better than the multi-model average in the Aerosol Comparisons between Observation and Models (AEROCOM) initiative in terms of the spatial and temporal distribution of Arctic BC.