Combined Lab, Field, and Modeling Studies Aimed to Improve our Understanding of Sources of Ice Nuclei and their Impact on Western US Precipitation Processes

该项目建立在2009年至2011年在加州进行的CalWater研究的基础上，该研究调查了长途运输的尘埃和生物颗粒对内华达山脉云层和降水过程的影响。这是由能源部和国家海洋和大气管理局赞助的一个更大项目的一部分。这项研究旨在更好地了解大气中气溶胶和云之间的相互作用，以及这些相互作用如何影响降水过程。这一结果可能对最近遭受干旱的加州地区很重要。该项目将解决3个问题：(1)矿物粉尘、陆地和海洋生物起源的冰核特性在何种制度下影响混合相降水云系统？(2)冰核（IN）活性谱在尘、生物尘和生物海洋气溶胶之间有何差异，这些差异能否在数值天气预报模式中得到充分体现？(3)是否存在最佳溶氧量浓度情景，以及云微物理和动力响应，使降水增强？单个粒子和IN的质谱将在地面站点使用气溶胶飞行时间质谱（ATOFMS）进行测量，并结合地面和美国能源部飞机上的其他仪器（包括连续流动扩散室（CFDC））的数据，以提供有关气溶胶混合状态和来源的信息。气象研究与预报模式的气溶胶形态谱仓微物理（WRF-ASBM）将以云分辨分辨率运行，并受测量的气溶胶化学类型、IN浓度、云水含量和云内图像测量的水流星类型的限制。观测结果将用于约束和验证气溶胶云成核、水流星-水流星相互作用和降水的高级数值模式模拟。该结果将对气溶胶-云相互作用研究领域产生重大影响。

This project builds upon the CalWater study conducted in 2009-2011 in California that investigated the impact of dust and bioparticles transported over long distances on clouds and precipitation processes over the Sierra Nevada mountain range. It is part of a larger project sponsored by the Department of Energy and the National Oceanic and Atmospheric Administration. This research seeks to gain a better understanding of the interactions between aerosols and clouds in the atmosphere and how these interactions influence precipitation processes. The results may be important for areas of California suffering from recent drought.The project will address 3 questions: (1) Under which regimes do the ice nucleating properties of mineral dust, terrestrial, and marine biology origin impact mixed-phase, precipitating cloud systems? (2) How do the ice nuclei (IN) activity spectra differ between dust, bio-dust and bio-marine aerosols, and can these differences be adequately represented in numerical weather prediction models? And (3) Do scenarios of optimal IN number concentration, together with cloud microphysics and dynamic responses exist such that precipitation is enhanced? Individual particle and IN mass spectra will be measured at a ground site using aerosol time-of-flight mass spectrometry (ATOFMS) and combined with data from other instruments on the ground and on the DOE aircraft, including a continuous flow diffusion chamber (CFDC), to provide information on the mixing state and sources of the aerosols. The Weather Research and Forecast model with aerosol speciated spectral bin microphysics (WRF-ASBM) will be run at cloud-resolving resolution and constrained by measured aerosol chemical type, IN concentrations, cloud water content and hydrometeor type measured by in-cloud imagery. The observations will be used to constrain and validate advanced numerical model simulations of aerosol cloud nucleation, hydrometeor-hydrometeor interaction, and precipitation. The results will have major implications for the field of aerosol-cloud interaction studies.