Radiative Transfer in Absorbing Aerosols and Snow Grains: Theory and Experiment

该项目是首席研究员长期以来对冰的辐射传输特性研究的发展，并将注意力转向由不同大小、形状和成分的黑碳（烟灰）和灰尘颗粒污染的冰粒和雪粒所改变的光的吸收和散射。这项研究将采用实验室实验、数值模拟和理论方法相结合的方法，这将部分取决于几何光子跟踪方法，以更好地确定污染冰在可见光和红外波长下的辐射散射特性。将进行系统的分析，以提高对物理的理解和对计算有效的方法的洞察力，这些方法是从一个代表单个和多个雪层的辐射传输模型中得出雪反照率（即能量反射率），其中包括雪颗粒大小和形状的各种组合、黑碳/尘埃-雪混合物以及太阳辐射入射角的实际变化。这项工作的智力价值在于为减少与不断变化的大气和积雪条件有关的气候系统强迫的不确定性提供了坚实的理论和基于模式的基础。更广泛的影响将来自以下方面：通过改进模式预测和相关改进敏感地区（包括但不限于冰川山脉和极地地区）的水资源管理，以及通过研究生和本科两级的学生教育，提高预测积雪迅速变化的能力。

This project is an evolution of the Principal Investigator's longstanding research on radiative transfer properties of ice, and turns attention to the absorption and scattering of light as altered by contamination of ice particles and snow grains by black carbon (soot) and dust particles of various sizes, shapes and composition. A combination of laboratory experimentation, numerical simulations and theoretical approaches will be applied to this investigation, which will in-part hinge on a geometric photon tracing method to better determine radiative scattering properties of contaminated ice at both visible and infrared wavelengths. A systematic analysis will be undertaken to improve physical understanding and insight into computationally efficient methodologies deriving snow albedo (i.e. energy reflectance) from a radiative transfer model representing both single and multiple snow layers that include a variety of combinations of snow grain size and shape, black carbon/dust-snow mixtures, and realistic variations of the incident angle of solar radiation.The intellectual merit of this work relates to providing a firm theoretical and model-based foundation for reducing uncertainties in climate system forcing associated with changing atmospheric and snowpack conditions. Broader impacts will derive from improved ability to anticipate rapid changes in snowcover via improved model predictions and associated improvements in water resource management in sensitive areas, including but not limited to glaciated mountains and polar regions, as well as through student education at both graduate and undergraduate levels.