Seasonal Variation of Wet Deposition of Black Carbon at Ny‐Ålesund, Svalbard
Seasonal Variation of Wet Deposition of Black Carbon at Ny‐Ålesund, Svalbard
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DOI：
10.1029/2020jd034110
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发表时间：
2021-06
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通讯作者：
T. Mori;Y. Kondo;S. Ohata;K. Goto‐Azuma;K. Fukuda;Yoshimi Ogawa‐Tsukagawa;N. Moteki;Atsushi Yoshida;M. Koike;P. Sinha;N. Oshima;H. Matsui;Y. Tobo;M. Yabuki;W. Aas
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作者：
T. Mori;Y. Kondo;S. Ohata;K. Goto‐Azuma;K. Fukuda;Yoshimi Ogawa‐Tsukagawa;N. Moteki;Atsushi Yoshida;M. Koike;P. Sinha;N. Oshima;H. Matsui;Y. Tobo;M. Yabuki;W. Aas
黑碳（BC）气溶胶沉积在北极雪中和雪上，增加了雪对太阳辐射的吸收，加速了雪的融化。北极大气和雪中的BC浓度受湿沉降控制;然而，由于缺乏对水凝物中BC的时间分辨测量，人们对这一过程的细节知之甚少。我们在2012-2019年期间在斯瓦尔巴德群岛的Ny‐ Sellesund分别以16%和15%的准确度测量了水凝物（CMBC）和空气（MBC）中的BC质量浓度。每月MBC和CMBC的中位数显示出相似的季节变化，冬春季高，夏季低。中位月BC湿沉降质量通量（FMBC）在冬季最高，夏季最低，与CMBC和降水的季节模式。除夏季外，水凝物中的季节平均BC粒径分布相似。2017年春季对MBC和CMBC的测量显示出与尺寸无关的去除效率，表明含BC的颗粒被有效地活化成云滴。将2013-2017年期间在纽约州的这些观测结果与阿拉斯加州巴罗的观测结果进行了比较。在纽约州和巴罗的近地表MBC具有相似的季节性模式;然而，这两个站点在CMBC和FMBC方面有所不同。在夏季，纽约州的CMBC较低，但巴罗的中等，可能反映了对流层低层MBC的差异。在这两个地点，水凝物的季节平均BC粒径分布相似，表明北极对流层低层的平均BC粒径分布相似。BC去除效率在运输过程中往往与尺寸无关，导致观察到的相似性。
Black carbon (BC) aerosol deposited in and onto Arctic snow increases the snow's absorption of solar radiation and accelerates snowmelt. Concentrations of BC in the Arctic atmosphere and snow are controlled by wet deposition; however, details of this process are poorly understood owing to the scarcity of time‐resolved measurements of BC in hydrometeors. We measured mass concentrations of BC in hydrometeors (CMBC) and in air (MBC) with 16% and 15% accuracies, respectively, at Ny‐Ålesund, Svalbard during 2012–2019. Median monthly MBC and CMBC values showed similar seasonal variations, being high in winter‐spring and low in summer. Median monthly BC wet deposition mass flux (FMBC) was highest in winter and lowest in summer, associated with seasonal patterns of CMBC and precipitation. Seasonally averaged BC size distributions in hydrometeors were similar except for summer. Measurements of MBC and CMBC in spring 2017 showed a size‐independent removal efficiency, indicating that BC‐containing particles were efficiently activated into cloud droplets. These observations at Ny‐Ålesund were compared with observations at Barrow, Alaska, during 2013–2017. The near‐surface MBC at Ny‐Ålesund and Barrow had similar seasonal patterns; however, the two sites differed in CMBC and FMBC. In summer, CMBC was low at Ny‐Ålesund but moderate at Barrow, likely reflecting differences in MBC in the lower troposphere. Seasonally averaged BC size distributions in hydrometeors were similar at both sites, suggesting that average BC size distributions are similar in the Arctic lower troposphere. The efficiency of BC removal tends to be size‐independent during transport, leading to the observed similarity.