Abstract

We compare the time variations in monthly average concentrations of black carbon in the surface air layer obtained from field measurements ([BC]) and from MERRA-2 reanalysis ([BC]_M) at four monitoring sites located in the northern part of Russia (Tiksi Observatory, Pechora-Ilych Biosphere Reserve), Alaska (Barrow station), and Greenland (Summit station). It is shown that the MERRA-2 reanalysis data for the regions of Tiksi and Barrow do not completely reflect the [BC] variations during the year, in contrast to the Pechora-Ilych Biosphere Reserve, where the discrepancies are within 30–50%. The [BC]_M reanalysis products for the Summit monitoring site qualitatively agree with the measurements characterizing the BC content in the free troposphere, but they underestimate [BC] by more than a factor of two. On the whole, our analysis showed that the results of the MERRA-2 reanalysis of the monthly average indices of near-surface concentration of atmospheric black carbon can be used for climate assessments for hard-to-reach northern regions in the warm season with an error of about 30%. Possible causes for the discrepancies between [BC] and [BC]_M are discussed for different times of the year and observation sites.

中文翻译：

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远离排放源的近地表大气中的黑碳：测量值和MERRA-2再分析数据的比较

摘要

我们比较了通过实地测量（[BC]）和MERRA-2再分析（[BC] _M）在俄罗斯北部的四个监测点获得的地表空气层中黑碳每月平均浓度的时间变化（提克西天文台，Pechora-Ilych生物圈保护区，阿拉斯加（巴罗站）和格陵兰（顶峰站）。结果表明，与Pechora-Ilych生物圈保护区的差异在30％至50％之内的情况相比，提克西和巴罗地区的MERRA-2再分析数据不能完全反映一年中的[BC]变化。[BC] _MSummit监视站点的再分析产品在质量上与表征自由对流层中BC含量的测量结果一致，但它们低估[BC]两倍以上。总体而言，我们的分析表明，MERRA-2对大气黑碳近地表浓度月平均指数的重新分析结果可用于在暖季难以到达的北部地区进行气候评估。误差约30％。讨论了一年中不同时间和观测地点之间[BC]和[BC] _M之间差异的可能原因。