Aerosols and nucleation in eastern China: first insights from the new SORPES-NJU station
Aerosols and nucleation in eastern China: first insights from the new SORPES-NJU station
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中国东部的气溶胶和成核：新 SORPES-NJU 站的初步见解
DOI：
10.5194/acp-14-2169-2014
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发表时间：
2014-01-01
影响因子：
6.3
通讯作者：
Fu, C. B.
中科院分区：
文献类型：
--
作者：
Herrmann, E.;Ding, A. J.;Fu, C. B.
利用南京大学地球系统区域过程观测站对长江三角洲西部地区气溶胶和新粒子的形成进行了研究。空气离子谱仪测量了直径0.8 ~ 42 nm的空气离子，差分迁移率粒度仪（DMPS）提供了6 ~ 800 nm的粒子数尺寸分布。此外，还记录了气象数据、微量气体浓度和PM2.5值。在2011年11月18日至2012年3月31日的监测期间，发现平均总颗粒浓度为23000 cm(-3), PM2.5平均值为90 μ g(-3)，远高于国家限值。我们观察到在测量期间发生了26个新的粒子形成事件，以大约1 cm(-3) s（-1）的速率产生了6 nm的粒子。典型的颗粒生长速率在6 ~ 7 nm h（-1）之间。据估计，平均而言，新粒子的形成和生长使云凝结核的浓度在这些事件日增加了约两倍。离子测量显示典型的簇带低于2 nm，总离子浓度约在600至1000 cm（-3）之间。离子测量的一个特殊特征是，在事件发生的前一天晚上，离子簇浓度升高。在2nm处，带电粒子的形成速率仅占总速率的0.2%左右，表明离子诱导成核的作用微乎其微。在观测的基础上，推导出一个简单的经验准则来估计粒子的形成概率。该判据以辐射和相对湿度为主导，预测颗粒形成的准确度可达90%。以类似的方式，得出了对粒子形成速率的相当准确的估计。结合起来，这些参数允许基于几个基本测量变量的粒子形成描述。
Aerosols and new particle formation were studied in the western part of the Yangtze River Delta (YRD) at the Station for Observing Regional Processes of the Earth System, Nanjing University (SORPES-NJU). Air ions in the diameter range 0.8-42 nm were measured using an air ion spectrometer, and a differential mobility particle sizer (DMPS) provided particle number size distributions between 6 and 800 nm. Additionally, meteorological data, trace gas concentrations, and PM2.5 values were recorded. During the measurement period from 18 November 2011 to 31 March 2012, the mean total particle concentration was found to be 23 000 cm(-3) and the mean PM2.5 value was 90 mu g m(-3), well above national limits. We observed 26 new particle formation events occurred during the measurement period, producing 6 nm particles at a rate of about 1 cm(-3) s(-1). Typical particle growth rates were between 6 and 7 nm h(-1). On average, new particle formation and growth were estimated to enhance cloud condensation nuclei concentration by about a factor of two during these event days. Ion measurements showed the typical cluster band below 2 nm, with total ion concentrations between about 600 and 1000 cm(-3). A peculiar feature of the ion measurements were heightened ion cluster concentrations during the nights before the event days. At 2 nm, the formation rate of charged particles was only about 0.2% of the total rate, pointing towards an only marginal role of ion-induced nucleation. Based on observations, a simple empirical criterion was deducted to estimate particle formation probability. Dominated by radiation and relative humidity, the criterion can predict the occurrence of particle formation with a 90% accuracy. In a similar fashion, a reasonably accurate estimate of particle formation rates was derived. Combined, these parameters allow for a description of particle formation based on a few basic measured variables.