Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, Campus Box 8208, Raleigh, North Carolina 27695-8208, USA.
J Phys Chem A. 2012 Oct 4;116(39):9706-17. doi: 10.1021/jp3064454. Epub 2012 Sep 24.
Aerosols are prevalent in the atmosphere where they can serve as cloud condensation nuclei (CCN). Here we report on new CCN measurements to characterize the temperature dependence of CCN activity for single component organic aerosol and secondary organic aerosol from the reaction of α-pinene and O(3) generated in the laboratory. For compounds with a weak dependence of water activity on temperature, the critical supersaturation of the particles can be well-modeled using temperature-dependent surface tension and Köhler theory. We also demonstrate that Köhler theory is valid for sparingly soluble compounds and can quantitatively explain the temperature-dependent activation properties of adipic acid aerosol over a broad range of temperatures. Accounting for temperature-dependent surface tension strongly affects CCN activity, and we anticipate that including this effect in global and regional model simulations may significantly change the estimated aerosol indirect forcing.
气溶胶在大气中很普遍，它们可以作为云凝结核（CCN）。在这里，我们报告了新的 CCN 测量结果，以表征单一组分有机气溶胶和源自α-蒎烯与 O（3）反应的二次有机气溶胶的 CCN 活性对温度的依赖性，这些气溶胶是在实验室中生成的。对于水活度对温度依赖性较弱的化合物，可以使用随温度变化的表面张力和克勒尔理论很好地模拟颗粒的临界过饱和度。我们还证明，克勒尔理论对于难溶性化合物也是有效的，并且可以定量解释在很宽的温度范围内己二酸气溶胶的温度依赖性活化特性。考虑到随温度变化的表面张力会强烈影响 CCN 活性，我们预计在全球和区域模型模拟中包含这一效应可能会显著改变对气溶胶间接强迫的估计。
