Arctic Aerosol Chemistry and Indirect Climate Effects

北极气溶胶的一般季节气候学和化学成分基本上已经很好地了解，但有机化合物的贡献还不清楚。在低纬度地区，有机物在气候强迫中发挥着重要作用。气溶胶对北极气候的直接辐射效应已经确定，但我们对间接效应（通过云微物理相互作用）的了解仍然不完整。 特别是，需要进一步了解气溶胶作为云凝结核和增强低层水云反射率的过程，这种现象称为第一气溶胶间接效应，提供资金在阿拉斯加的巴罗进行取样方案，以确定北极气溶胶全年的有机部分，并确定功能群组成，这一研究旨在确定可能的人为来源，并为在气候变化研究中严格纳入北极气溶胶化学成分提供基础。主要研究人员将在巴罗部署一个新的短波分光辐射计，覆盖波长范围为0.35 - 2.5微米，这将提供高时间分辨率的数据，用于反演云的热力学相位，液体/冰水路径和有效粒子半径。利用来自美国能源部大气辐射测量计划巴罗站点的补充数据，他们将能够量化第一个气溶胶间接效应的短波分量，并且通过他们将获得的关于有机物的新理解，了解液态水路径和有效半径对第一个气溶胶间接效应的贡献。

The general seasonal climatology and chemical composition of Arctic aerosol are basically well understood, but the contribution from organic compounds is not. At lower latitudes, organics are known to play a large role in climate forcing. The direct radiative effects of aerosol on Arctic climate have been identified, but our knowledge of indirect effects (via cloud microphysical interactions) is still incomplete. In particular, further understanding is needed of the processes through which aerosols serve as cloud condensation nuclei and enhance the reflectivity of low-level water clouds, a phenomenon known as the first aerosol indirect effect.Funds are provided to carry out a sampling program at Barrow, Alaska, to determine the fraction of Arctic aerosol that is organic, throughout the year, and identify functional group composition, possible anthropogenic sources, and to provide a basis for rigorous incorporation of Arctic aerosol chemical composition in climate change studies. The principal investigators will deploy a new shortwave spectroradiometer at Barrow, covering the wavelength range 0.35 - 2.5 microns, which will provide high-time-resolution data for retrieval of cloud thermodynamic phase, liquid/ice water path, and effective particle radius. With supplemental data from the U.S. Department of Energy Atmospheric Radiation Measurement Program site at Barrow, they will thus be able to quantify the shortwave component of the first aerosol indirect effect and, through the new understanding they will gain about organics, understand both liquid water path and effective radius contributions to the first aerosol indirect effect.