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2009-2011年在加州进行的CalWater研究的基础上，该研究调查了长距离传输的灰尘和生物颗粒对内华达州山脉上空的云和降水过程的影响。 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。该研究结果对最近遭受干旱的加州地区可能是重要的。该项目将解决3个问题：（1）在哪些制度下，矿物尘，陆地和海洋生物起源的冰成核特性影响混合相，降水云系统？(2)冰核（IN）活动谱在尘埃、生物尘埃和生物海洋气溶胶之间有何不同，这些差异在数值天气预报模式中是否能得到充分的体现？以及（3）是否存在最佳IN数浓度的情景，以及云微物理和动力响应，从而使降水增强？将在地面站点使用气溶胶飞行时间质谱仪（ATOFMS）测量单个粒子和IN质谱，并将其与地面和DOE飞机上的其他仪器（包括连续流扩散室（CFDC））的数据相结合，以提供有关气溶胶混合状态和来源的信息。将以云分辨分辨率运行带有气溶胶形成光谱箱微物理学的天气研究和预报模型，并受测得的气溶胶化学类型、IN浓度、云水含量和云中图像测得的水凝物类型的约束。 观测结果将用于约束和验证气溶胶云成核、水凝物-水凝物相互作用和降水的高级数值模型模拟。研究结果将对气溶胶-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.