Size-resolved flux measurement of sub-micrometer particles over an urban area
Size-resolved flux measurement of sub-micrometer particles over an urban area
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DOI：
10.1127/0941-2948/2013/0441
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发表时间：
2013-12-01
影响因子：
1.2
通讯作者：
Klemm, Otto
中科院分区：
文献类型：
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作者：
Deventer, Malte Julian;Griessbaum, Frank;Klemm, Otto
2011年4月11日至5月27日，在德国西北部城市明斯特上空对城市边界层与城市地表之间的亚微米颗粒物湍流交换进行了观测。研究的范围是检查不同大小的颗粒类的总测量通量的贡献。涡度协方差测量进行了65米以上的地面。用光学粒子谱仪测量了99个粒径为55 ~ 1000 nm的粒子浓度。对于通量计算，我们将这99个原始箱分组为18个更宽的通道，上限为320 nm，以及一个更粗的通道，用于1 μ m以下的颗粒。总体结果显示，Munster是约2.8的相关源。10（8）个颗粒m（-2）d（-1）在工作日和1.8。10（8）个颗粒m（-2）d（-1）（周日）在指定的尺寸范围内。这些排放主要是由艾特肯模式的二次粒子驱动的，这很可能是由交通造成的。因此，交通热点是净流量的主要贡献。另一方面，考虑到质量通量，明斯特是一个汇0.53 μ g m（-2）d（-1）在工作日和0.08 μ g m（-2）d（-1）在星期日。这里，主要是直径大于167 nm的聚集模式的颗粒导致沉积通量。数量和质量通量表现出不同的每日和每周模式。
From April 11th to May 27th, 2011, the turbulent exchange of sub-micrometer particles between the urban surface and the urban boundary-layer was measured above the city area of Munster (NW Germany). The scope of the study is to examine the contributions of particles of different size classes to the total measured fluxes. Eddy-covariance measurements were performed at 65 m above ground. The particle concentrations in 99 size bins with particle diameters ranging from 55 to 1000 nm were measured with an optical particle spectrometer. For flux calculations we grouped these 99 original bins into 18 wider channels with an upper cut-off of 320 nm, and a further rather coarse channel for particles up to 1 mu m. The overall results reveal that Munster is a relevant source of about 2.8 . 10(8) particles m(-2) d(-1) on weekdays and 1.8 . 10(8) particles m(-2) d(-1) on Sundays within the indicated size range. These emissions are predominantly driven by secondary particles of the Aitken mode, which are most likely caused by traffic. Hence traffic hotspots are a major contribution to the net fluxes. On the other hand, considering the mass fluxes, Munster is a sink of 0.53 mu g m(-2) d(-1) on weekdays and 0.08 mu g m(-2) d(-1) on Sundays. Here, mainly particles of the accumulation mode with diameters above 167 nm lead to deposition fluxes. Number and mass fluxes exhibit distinct daily and weekly patterns.