Interactions of Aerosol Particles and Marine Stratocumulus Clouds

该项目的目标是描述层积云上方、中和下方的气溶胶粒子的化学和物理特征。这项研究将作为DYCOMS-II项目(海洋层积云的动力学和化学)的一部分，于2001年7月在加利福尼亚州海岸外进行。将通过比较云内和云外测量的粒子的尺寸分布和化学成分来评估气溶胶和云粒子的相互作用。对云滴大小分布的测量将用于研究气溶胶粒子对云微物理特性的影响。仪器包括尺寸范围为0.005至6400微米的粒子谱仪。气溶胶样品的电子显微镜将用于识别化学官能团，包括有机物种和元素。通过逆流虚拟撞击收集的云滴残留物将以同样的方式进行分析。这些数据将有助于深入了解下列科学问题：(1)纳入云滴的颗粒的化学成分；(2)不同气溶胶化学类型和尺寸分布对云微物理的影响；(3)云对气溶胶的化学处理程度；(4)观测结果可在多大程度上用物理和化学云模式进行近似。这项研究的最终目标是提高在大气环流和气候的大尺度模式中对云的辐射、动力和热力学效应进行参数化的能力。

The objective of this project is to characterize the chemical and physical characteristics of aerosol particles above, in, and below stratocumulus clouds. The study will be carried out as part of the DYCOMS-II project (Dynamics and Chemistry of Marine Stratocumulus), off the California coast in July 2001. The interaction of aerosol and cloud particles will be evaluated by comparing the size distributions and chemical composition of particles measured within cloud with those outside the cloud. Measurements of the cloud droplet size distribution will be used to investigate the effects of aerosol particles on cloud microphysical properties. Instrumentation includes particle spectrometers for the size range 0.005 to 6400 micrometers. Electron microscopy of aerosol samples will be used to identify chemical functional groups, including organic species, and elements. The residue of cloud droplets collected by counterflow virtual impaction will be analyzed the same way. The data will give insight on the following scientific problems: (1) the chemical composition of particles incorporated into cloud droplets; (2) the effects of different aerosol chemical types and size distributions on cloud microphysics; (3) the degree of chemical processing of the aerosols by cloud; (4) the extent to which the observations can be approximated by physical and chemical cloud models. The ultimate goal of the research is to improve the ability to parameterize the radiative, dynamic, and thermodynamic effects of clouds in large-scale models of atmospheric circulation and climate.