Doctoral Dissertation Research: Evaluation of a Subcanopy Solar Radiation Model Under Real-Sky Conditions with Field Validation Measurements

这项博士论文研究项目将研究地形、森林覆盖和天空条件之间复杂的相互作用对太阳辐射的影响，从而提供更准确和更高分辨率的太阳辐射到达地面的估计。该项目将提高研究人员和从业人员的能力，将大气条件和植被的影响纳入太阳辐射模型，这是推进关于地表太阳辐射、热通量以及地下水和地表水温度动态研究所必需的。除了评估一种高分辨率、空间上明确的方法来估计穿过大片地区的森林冠层的太阳辐射量外，该项目还将演示将真实天空条件纳入到溪流温度建模中的方法。将由博士生开发的综合模型将有可能成为一个强大的、空间上明确的工具，用于展示河流过程、土地管理和生态系统结果之间的联系，这些结果可以适应广泛的自然和人为改变的环境。作为博士论文研究改进奖，该奖项还将提供支持，使有前途的学生建立一个强大的独立研究生涯。该项目还将为另一名担任该项目技术人员的研究生提供宝贵的跨学科合作研究经验。最近开发的一种利用机载激光雷达数据并与开源裸地太阳辐射模型集成的冠层下太阳辐射建模方法表明，可以估计透过森林冠层的光穿透，并用于生成植被景观的冠层下太阳辐射的高分辨率估计。该太阳辐射模型允许对大气条件的影响进行参数化，其中到达冠层表面的太阳辐射受到大气气溶胶、水蒸气和云的影响。然而，在美国的大多数地区，对大气条件进行参数化所需的信息并不广泛。虽然可以使用代表统一晴朗或阴天的天空条件的值或公布的历史平均值，但更能代表真实天空条件的值应该会提高对特定地点和时间段的太阳辐射估计的准确性。这位博士生将在太阳辐射模拟的这些最新进展和遥感数据可用性增加的基础上，通过结合大气条件、森林树冠和地形的综合影响来改进对阿巴拉契亚南部源头盆地树冠下太阳辐射的估计。学生将开发开放式科学工作流程，使用现有的方法和现有的卫星数据计算林克浑浊度值和晴空指数，以实现大气条件的参数化。她将使用常规和计算的大气条件参数来测试太阳辐射模型的有效性，并将通过对树冠下太阳辐射的现场测量来评估模型的准确性。她还将确定纳入真实天空和森林树冠条件来估计太阳辐射是否提高了蒸汽温度估计的准确性。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This doctoral dissertation research project will study the complex interactions among topography, forest cover, and sky conditions on solar insolation, thereby providing more accurate and higher-resolution estimates of solar radiation reaching the ground surface. The project will enhance the capabilities of researchers and practitioners to incorporate the effects of atmospheric conditions and vegetation in solar radiation models that are needed to advance research about surface solar radiation, heat flux, and ground and surface water temperature dynamics. In addition to evaluating a high-resolution, spatially explicit approach to estimating the amount of solar radiation penetrating forest canopies over extensive areas, this project will demonstrate methods for incorporating real-sky conditions in the modeling of stream temperatures. The integrative model to be developed by the doctoral student will have the potential to be a powerful, spatially explicit tool for demonstrating linkages among stream processes, land-management, and ecosystem outcomes that can be adapted to a broad range of natural and human-modified environments. As a Doctoral Dissertation Research Improvement award, this award also will provide support to enable a promising student to establish a strong independent research career. The project also will provide valuable experience in collaborative interdisciplinary research for another graduate student serving as a technician on this project.A recently developed subcanopy solar radiation modeling method that uses airborne LiDAR data and is integrated with an open-source, bare-earth solar radiation model demonstrated that light penetration through forest canopies could be estimated and used to produce high resolution estimates of subcanopy solar radiation for vegetated landscapes. That solar radiation model allows parameterization of the effects of atmospheric conditions where the solar radiation reaching the canopy surface is affected by atmospheric aerosols, water vapor, and clouds. The information needed to parameterize atmospheric conditions is not widely available for most locations in the United States, however. Although values representing uniformly clear or overcast sky conditions or published values of historic averages can be used, values more representative of real-sky conditions should improve the accuracy of the solar radiation estimates for specific locations and time periods. The doctoral student will build on these recent advances in solar radiation modeling and the increased availability of remotely sensed data by incorporating the combined effects of atmospheric conditions, forest canopies, and topography to improve estimates of subcanopy solar radiation in a Southern Appalachian headwater basin. The student will develop open-science workflows to compute the Linke Turbidity value and the clear sky index using existing methods and available satellite data for the parameterization of atmospheric conditions. She will test the validity of the solar radiation models with general and computed atmospheric condition parameters, and she will evaluate model accuracy with field measurements of subcanopy solar radiation. She also will determine whether the inclusion of real-sky and forest canopy conditions to estimate solar radiation improves the accuracy of steam temperature estimates.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.