Collaborative Research: Impacts of Mineral Dust on the Lifecycle of Tropical Convection

将通过观测分析和数值模拟相结合的方法，研究热带大西洋盆地上空有组织对流云系中矿物尘埃作为云凝结和冰核的影响。 将利用区域大气模拟系统进行理想化的模拟，以进一步研究沙尘气溶胶对热带对流云和降水的影响，并将以2006年大西洋飓风季节进行的美国航天局非洲季风多学科活动项目NAMMA期间收集的观测结果为指导。将详细模拟一场实际风暴（热带风暴黛比）的生命周期，这场风暴显然受到东大西洋上空撒哈拉尘埃摄入的影响。 将研究撒哈拉空气层的动力学和辐射影响，并评估直接和间接气溶胶效应的相对重要性以及撒哈拉空气层本身的环境影响-包括湿度、温度和垂直风切变。 将利用国家科学基金会支持的PREDICT的额外观测来检查到达远西大西洋的老龄尘埃对该地区深对流云的观测（热带地区云系的前萧条调查）实验，这项工作的智力价值集中在提高对云过程的理解上（特别是云和降水微物理学）在受到来自遥远大陆区域的尘埃和其他气溶胶影响的情况下，以及确定这些影响可能有利于或不利于热带风暴和飓风形成的程度。更广泛的影响将通过来自代表性不足的小组的两名主要调查员的支持来实现（即大气科学方面的妇女），通过大学培训和研究生实地经验相结合，并最终通过提高预测沙尘引起的热带风暴形成和（或）强度变化的能力，这对准确预报大西洋盆地飓风至关重要。

The effects of mineral dust acting as both cloud condensation and ice nuclei within organized convective cloud systems over the tropical Atlantic basin will be investigated through a combination of observational analysis and numerical simulations. Idealized simulations will be conducted using the Regional Atmospheric Modeling System (RAMS) to further examine dust aerosol impacts on tropical convective clouds and precipitation are to be guided by observations collected during NAMMA, NASA's African Monsoon Multidisciplinary Activities project, conducted during the 2006 Atlantic hurricane season. The lifecycle of an actual storm (Tropical Storm Debby), which was apparently influenced by ingestion of Saharan dust over the eastern Atlantic, will be simulated in detail. The dynamical and radiative impacts of the Saharan Air Layer (SAL, which carries dust westward from Africa) will be studied, and the relative importance of direct and indirect aerosol effects as well as environmental influences of the SAL itself--including humidity, temperature and vertical wind shear--will be assessed. Observations of aged dust reaching the far western Atlantic upon deep convective clouds in that region will be examined using additional observations from the NSF-supported PREDICT (Pre-Depression Investigation of Cloud-systems in the Tropics) experiment in 2010.The intellectual merit of this effort centers on improved understanding of cloud processes (and in particular cloud and precipitation microphysics) in the presence of influences by dust and other aerosols originating over distant continental regions, and determination of the extent to which these influences may favor or disfavor tropical storm and hurricane formation.Broader impacts will come through support of two principal investigators drawn from an underrepresented group (viz. women in the atmospheric sciences), through a combination of university training and field experience for a graduate student, and ultimately through improved ability to anticipate dust-induced changes in tropical storm formation and/or intensity key to accurate forecasts of Atlantic basin hurricanes.