Development of a Near-UV Aerosol Albedometer

众所周知，大气颗粒物，无论是自然的还是人为的，通过散射和吸收太阳辐射直接改变地球的辐射平衡。 然而，气溶胶的直接辐射效应的确切大小仍然有些不确定。 虽然一直在研究在可见光和近红外线范围内确定气溶胶特性的技术，但对在光谱的近紫外线部分内确定气溶胶的直接光学特性的关注较少。 这项工作的重点是开发一种仪器，以测量气溶胶散射系数，消光系数，并在紫外波长相关的单散射。 该仪器将利用研究人员以前开发的方法，在该方法中，对分散在积分球内的同一气溶胶样品同时测量气溶胶散射和消光系数。 消光将使用“腔衰荡”技术测量，而散射测量将通过用积分球收集从探测光束散射的光来进行。 该项目计划分三个步骤，即构建仪器，在实验室环境中优化和表征其性能，然后对气溶胶光学特性进行环境监测。该研究的智力价值在于提供关键测量值，以帮助缩小当前近紫外气溶胶直接光学表征能力方面的重大差距。更广泛的影响包括增加对气溶胶的了解与气候研究相关的强迫。 将通过支助两名女研究生和几名本科生，强调教育和扩大参与方面。 公共宣传将包括在校园内有许多游客的时期（如周末体育赛事），让公众有机会看到人类活动，如户外烹饪如何改变大气成分。

It is well established that atmospheric particulates, both natural and anthropogenic, directly alter earth's radiative balance by scattering and absorbing solar radiation. The exact magnitude aerosol's direct radiative effect nonetheless remains somewhat uncertain. While research on techniques to characterize aerosols in the visible and near infrared has been ongoing, there has been less attention paid to direct optical characterization of aerosols in the near-ultraviolet (UV) part of the spectrum. This effort will focus on development of an instrument to measure the aerosol scattering coefficient, extinction coefficient, and associated single-scatter albedo at UV wavelengths. This instrument will make use of methodology previously developed by the researchers in which aerosol scattering and extinction coefficients are measured simultaneously on the same aerosol sample dispersed within an integrating sphere. Extinction will be measured using the "cavity ring-down" technique while scattering measurements would be made by collecting light scattered from the probe beam with the integrating sphere. The three-step project plan is to construct the instrument, optimize and characterize its performance in a laboratory setting, and then perform ambient monitoring of aerosol optical properties.The intellectual merit of the research comes through development of provision of key measurements to help to close a major gap in current ability for direct optical characterization of aerosols in the near UV.Broader impacts include increased understanding of aerosol forcing relevant to climate research. Educational and broadening participation aspects will be emphasized via support for two female graduate students and several undergraduates. Public outreach will include a laboratory open-house during periods with many visitors on campus (such as weekend sporting events) to allow the general public an opportunity to see how human activities such as outdoor cooking can alter atmospheric composition.