Temperature-dependent accumulation mode particle and cloud nuclei concentrations from biogenic sources during WACS 2010
Temperature-dependent accumulation mode particle and cloud nuclei concentrations from biogenic sources during WACS 2010
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WACS 2010 期间生物来源的温度依赖性累积模式颗粒和云核浓度
DOI：
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发表时间：
2012
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通讯作者：
A. Macdonald
中科院分区：
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作者：
L. Ahlm;K. Shakya;L. Russell;J. Schroder;J. Wong;S. Sjostedt;K. Hayden;J. Liggio;J. Wentzell;H. Wiebe;C. Mihele;W. Leaitch;A. Macdonald
摘要。利用傅里叶变换红外光谱（FTIR）对2010年6月至7月在加拿大不列颠哥伦比亚省惠斯勒山山顶（海拔2182 m）和山间林地（海拔1300 m）同时采集的亚微米气溶胶粒子进行了有机官能团的定量分析。将正矩阵分解（PMF）技术应用于红外光谱分析。在两个地点都发现了与(1)燃烧、(2)生物源和(3)营养碎屑相关的三个PMF因子。生物成因因子与温度和几种挥发性有机物（VOCs）均有相关性。在运动开始时，当温度较低且平流来自温哥华地区时，燃烧因素主导亚微米颗粒质量，但随着7月初温度开始上升，生物源性VOCs排放增加，从而增加了二次有机气溶胶（SOA）的形成，生物源性因素开始占主导地位。平均而言，生物成因因子分别占惠斯勒峰和中山遗址亚微米有机粒子质量的69%和49%。中山立地植被碎屑含量较低，受当地燃烧源影响较大。生物成因因子与粒径（dp）为100 nm的颗粒数浓度呈极显著正相关（r ~0.9），燃烧因子与粒径（dp）为0.4的颗粒数浓度呈极显著正相关（r ~0.4）。当过饱和度(S)大于等于0.2%时，云凝结核数（CCN）浓度与生物成因因子呈显著相关（r ~0.7），表明生物成因蒸汽的粒子凝聚生长是控制S≥0.2%云的CCN浓度的重要因素。粒径为0 ~ 100 nm的颗粒数浓度和粒径≥0.2%的CCN数均与温度相关。考虑到生物因素的影响，这些结果表明温度是控制0.2%过饱和时CCN浓度的主要因素。
Abstract. Submicron aerosol particles collected simultaneously at the mountain peak (2182 m a.s.l.) and at a forested mid-mountain site (1300 m a.s.l.) on Whistler Mountain, British Columbia, Canada, during June and July 2010 were analyzed by Fourier transform infrared (FTIR) spectroscopy for quantification of organic functional groups. Positive matrix factorization (PMF) was applied to the FTIR spectra. Three PMF factors associated with (1) combustion, (2) biogenics, and (3) vegetative detritus were identified at both sites. The biogenic factor was correlated with both temperature and several volatile organic compounds (VOCs). The combustion factor dominated the submicron particle mass during the beginning of the campaign, when the temperature was lower and advection was from the Vancouver area, but as the temperature started to rise in early July, the biogenic factor came to dominate as a result of increased emissions of biogenic VOCs, and thereby increased formation of secondary organic aerosol (SOA). On average, the biogenic factor represented 69% and 49% of the submicron organic particle mass at Whistler Peak and at the mid-mountain site, respectively. The lower fraction at the mid-mountain site was a result of more vegetative detritus there, and also higher influence from local combustion sources. The biogenic factor was strongly correlated ( r ~0.9) to number concentration of particles with diameter ( D p )> 100 nm, whereas the combustion factor was better correlated to number concentration of particles with D p r ~0.4). The number concentration of cloud condensation nuclei (CCN) was correlated ( r ~0.7) to the biogenic factor for supersaturations ( S ) of 0.2% or higher, which indicates that particle condensational growth from biogenic vapors was an important factor in controlling the CCN concentration for clouds where S ≥0.2%. Both the number concentration of particles with D p >100 nm and numbers of CCN for S ≥0.2% were correlated to temperature. Considering the biogenic influence, these results indicate that temperature was a primary factor controlling these CCN concentrations at 0.2% supersaturation.