Physical characterization of aerosol particles during nucleation events
Physical characterization of aerosol particles during nucleation events
复制标题
DOI：
10.1034/j.1600-0889.2001.530403.x
复制
发表时间：
2001-09-01
影响因子：
2.3
通讯作者：
Kulmala, M
中科院分区：
文献类型：
--
作者：
Aalto, P;Hämeri, K;Kulmala, M
在芬兰Hyytiala进行的三次BIOFOR活动（1998年4月14日至5月22日、1998年7月27日至8月21日和1999年3月20日至4月24日）期间，从北方森林内部和上方的不同高度测量了颗粒浓度和大小分布。典型地，森林内的背景分布的形状表现出2种主要模式：精细或艾特肯模式，几何数平均直径为44 nm，平均浓度为1160 cm（-3），以及累积模式，平均直径为154 nm，平均浓度为830 cm（-3）。还存在粗模式，延伸至20 μ m的尺寸，具有1.2 cm（-3）的数浓度，2.0 μ m的体积平均直径和1.9的几何标准偏差。气溶胶湿度在测量期间低于50%。在许多天中观察到颗粒产生，通常发生在上午晚些时候。在这些新颗粒产生的时期下，观察到成核模式在直径为3 nm的数量级处形成，并且在大多数情况下，观察到该模式在一天的过程中生长成艾特肯模式尺寸。总浓度范围为410-45000 cm-3，最高浓度出现在颗粒产生日。一个明显的梯度之间的粒子浓度低于森林树冠和以上，与显着较低的浓度发生在树冠。在树冠上方，在18英寸和67英寸之间观察到轻微的梯度，在浓度增加最强烈的67英寸处观察到最高5%的浓度。
Particle concentrations and size distributions have been measured from different heights inside and above a boreal forest during three BIOFOR campaigns (14 April-22 May 1998, 27 July-21 August 1998 and 20 March-24 April 1999) in Hyytiala, Finland. Typically, the shape of the background distribution inside the forest exhibited 2 dominant modes: a fine or Aitken mode with a geometric number mean diameter of 44 nm and a mean concentration of 1160 cm(-3) and an accumulation mode with mean diameter of 154 nm and a mean concentration of 830 cm(-3). A coarse mode was also present, extending up to sizes of 20 mum having a number concentration of 1.2 cm(-3), volume mean diameter of 2.0 mum and a geometric standard deviation of 1.9. Aerosol humidity was lower than 50% during the measurements. Particle production was observed on many days, typically occurring in the late morning. Under these periods of new particle production, a nucleation mode was observed to form at diameter of the order of 3 nm and, on most occasions, this mode was observed to grow into Aitken mode sizes over the course of a day. Total concentrations ranged from 410-45000 cm(-3), the highest concentrations occurring on particle production days. A clear gradient was observed between particle concentrations encountered below the forest canopy and those above, with significantly lower concentrations occurring within the canopy. Above the canopy, a slight gradient was observed between 18 in and 67 in, with at maximum 5% higher concentration observed at 67 in during the strongest concentration increases.