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来研究矿物尘埃在热带大西洋盆地上空有组织的对流云系中既是云凝结又是冰核的影响。将使用区域大气模拟系统(RAMS)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，并根据在2006年大西洋飓风季节开展的美国航天局非洲季风多学科活动项目NAMMA期间收集的观测数据进行模拟。将详细模拟一个实际风暴(热带风暴黛比)的生命周期，该风暴显然受到东大西洋上空吸入撒哈拉沙尘的影响。将研究撒哈拉空气层(SAL)的动力和辐射影响，评估直接和间接气溶胶效应以及SAL本身--包括湿度、温度和垂直风切变--对环境的影响的相对重要性。2010年，美国国家科学基金会支持的预测(热带云系的低气压前调查)实验的额外观测将检验在该地区的深层对流云上观察到的陈年尘埃。这项工作的智力价值集中在更好地理解云过程(特别是云和降水的微物理)，在存在来自遥远大陆地区的尘埃和其他气溶胶的影响的情况下，以及确定这些影响可能在多大程度上有利于或不利于热带风暴和飓风的形成。更广泛的影响将通过来自代表不足的小组的两名主要研究人员的支持(即。通过大学培训和研究生的实地经验相结合，并最终通过提高预测热带风暴形成和/或强度变化的能力，这是准确预报大西洋盆地飓风的关键。

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.