POWRE: The Inhomogeneity of Stratocumulus Cloud Microstructure and Its Effect on Cloud Radiative Parameters

在研究和教育妇女职业机会（POWRE）计划下，首席研究员将研究层积云层辐射参数对云不均匀性的依赖关系。云的辐射特性对于从局部天气到气候问题的各种气象过程都是一个非常重要的因素。然而，目前对这些辐射特性的了解有些缺乏。Principal InvestigatorÆs的第一个任务是评估在各种应用和卫星检索中最常用的云光学深度参数化的准确性。评估将基于先进的研究数值模型的模拟，其中包括云微物理的明确公式。大西洋层积云试验、南大洋云试验和蒙特雷地区航迹试验的观测将为数值模式的初始化提供数据。基于已知液滴尺寸分布的精确解将与基于体积参数的参数化进行比较。预计这项研究将使人们更好地理解云的不均匀性对云辐射参数的影响，并改进它们在大尺度模型中的表述，因为大尺度模型无法适应云微物理的明确处理。第二个任务是定量地研究由平面平行或独立像素近似引入的偏差如何依赖于描述云微物理不均匀性的统计参数。表征空间非均匀性的参数将与平面平行和独立像素近似引入的偏差有关。对偏置的修正将提高层积云边界层云辐射传输计算的精度。这项在NSF power项目下的研究也将帮助首席研究员获得与辐射传输问题相关的最新数值模拟和观测方面的新专业知识。

9870492KoganUnder the Professional Opportunities for Women in Research and Education (POWRE) Program, the Principal Investigator will investigate the dependence of the stratocumulus cloud layer radiative parameters on cloud inhomogeneity. Radiative properties of clouds is a factor very important to a variety of meteorological processes that range from local weather to climate issues. Current knowledge of these radiative characteristics, however, is somewhat lacking.The Principal InvestigatorÆs first task is to evaluate the accuracy of cloud optical depth parameterizations that are most commonly used in various applications and satellite retrievals. The evaluation will be based on simulations with an advanced research numerical model which includes explicit formulation of cloud microphysics. The observations from the Atlantic Stratocumulus Experiment, Southern Ocean Cloud Experiment, and Monterey Area Ship Track Experiment will provide the data for the initialization of the numerical model. The exact solution based on the known drop size distributions will be compared with parameterizations based on bulk parameters. It is expected that the study will result in a better understanding of the effect of cloud inhomogeneity on cloud radiative parameters and improvement of their formulation in large-scale models that cannot accommodate explicit treatment of cloud microphysics.The second task win be to investigate quantitatively how the bias introduced by the plane-parallel or independent pixel approximation depends on the statistical parameters describing the cloud microphysical inhomogeneity. The parameters characterizing the spatial inhomogeneity will be related to the bias introduced by plane-parallel and independent pixel approximations. The correction of the bias will increase the accuracy of the radiative transfer calculations in the stratocumulus boundary layer clouds.This research under the NSF POWRE Program will also help the Principal Investigator to gain new expertise in the state of the art numerical modeling and observations related to the radiative transfer problems.