Controls on surface aerosol particle number concentrations and aerosol-limited cloud regimes over the central Greenland Ice Sheet
Controls on surface aerosol particle number concentrations and aerosol-limited cloud regimes over the central Greenland Ice Sheet
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DOI：
10.5194/acp-21-15351-2021
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发表时间：
2021-10
影响因子：
6.3
通讯作者：
H. Guy;I. Brooks;K. Carslaw;B. Murray;V. Walden;M. Shupe;C. Pettersen;D. Turner;C. Cox;W. Neff;R. Bennartz;R. Neely III
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文献类型：
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作者：
H. Guy;I. Brooks;K. Carslaw;B. Murray;V. Walden;M. Shupe;C. Pettersen;D. Turner;C. Cox;W. Neff;R. Bennartz;R. Neely III
抽象。这项研究介绍了在格陵兰冰盖中心（72.58 N，−38.45 E; 3250 ma.s.l.）的Summit站（Summit）收集的环境表面气溶胶粒子数浓度测量值（凝结核> 20 nm，N20）的第一个完整的年度周期（2019-2020）。2019年的平均表面浓度为129 cm−3，6小时平均值介于1和1441 cm−3之间。最高的月平均浓度出现在春末和夏季，最低浓度出现在2月（平均值：18 cm−3）。高N20事件与格陵兰岛上空的异常反气旋环流和自由对流层气溶胶下降到地面有关，而低N20事件与格陵兰岛东南部上空的异常气旋环流有关，后者驱动上坡气流并增强通往峰会的降水。雾强烈地影响颗粒数浓度，在雾形成的前3小时内平均减少20%的N20。极低的N20事件（< 10 cm−3）发生在所有季节，我们认为雾和潜在的云的形成，可以限制在格陵兰岛中部的低气溶胶粒子浓度。
Abstract. This study presents the first full annual cycle (2019–2020) of ambient surface aerosol particle number concentration measurements (condensation nuclei > 20 nm, N20) collected at Summit Station (Summit), in the centre of the Greenland Ice Sheet (72.58∘ N, −38.45∘ E; 3250 ma.s.l.). The mean surface concentration in 2019 was 129 cm−3, with the 6 h mean ranging between 1 and 1441 cm−3. The highest monthly mean concentrations occurred during the late spring and summer, with the minimum concentrations occurring in February (mean: 18 cm−3). High-N20 events are linked to anomalous anticyclonic circulation over Greenland and the descent of free-tropospheric aerosol down to the surface, whereas low-N20 events are linked to anomalous cyclonic circulation over south-east Greenland that drives upslope flow and enhances precipitation en route to Summit. Fog strongly affects particle number concentrations, on average reducing N20 by 20 % during the first 3 h of fog formation. Extremely-low-N20 events (< 10 cm−3) occur in all seasons, and we suggest that fog, and potentially cloud formation, can be limited by low aerosol particle concentrations over central Greenland.