Collaborative Research: Ice Supersaturation over the Southern Ocean and Antarctica, and its Role in Climate

冰的过饱和度在云的形成和演化中起着关键作用，它决定了冰、液、气三相之间的分配。在南大洋和南极洲，混合相云和冰云之间的过渡显著影响云的辐射效应。历史上，南极洲和南大洋等偏远地区的现场观测，特别是空中观测，采样不足。尽管人们对这些地区的云微物理特性给予了更多的关注，但在南半球较高纬度地区，冰过饱和的分布和特征及其在当前和未来气候中的作用还没有得到充分的研究。这项研究的主要目标之一是分析最近由美国国家科学基金会和美国能源部赞助的三个主要野外活动的观测结果，这些活动在南大洋上空提供密集的现场、航空测量和南极麦克默多站的地面观测。该项目将分析南大洋和南极洲上空的飞机和地面观测，并将观测结果与共同体地球系统模型版本2(CESM2)的模拟进行比较。重点将放在观测冰的过饱和度和混合相云和冰云中的相对湿度分布，以及它们与云的微观和宏观物理性质的关系。观察结果将与CESM2模拟进行比较，以阐明模型偏差。麦克默多站的地表辐射和降水收支将被量化，并与CESM2模拟进行比较，以提高南极气候(和南极洲气候预测)的再现的保真度。我们的研究结果将向社会公布，以提高对云辐射效应和南部高纬度水的质量输送的了解。模拟结果与观测结果的比较将为改进下一代CESM模式提供有价值的信息。皮奥将在圣何塞州立大学(SJSU)开展两个教育/外展项目，其中包括一个独特的本科生研究项目和一个利用社交媒体向公众传播极地研究新闻的外展项目。该项目利用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Ice supersaturation plays a key role in cloud formation and evolution, and it determines the partitioning among ice, liquid and vapor phases. Over the Southern Ocean and Antarctica, the transition between mixed-phase and ice clouds significantly impacts the radiative effects of clouds. Remote regions such as the Antarctica and Southern Ocean historically have been under-sampled by in-situ observations, especially by airborne observations. Even though more attention has been given to the cloud microphysical properties over these regions, the distribution and characteristics of ice supersaturation and its role in the current and future climate have not been fully investigated at the higher latitudes in the Southern Hemisphere. One of the main objectives of this study is to analyze observations from three recent major field campaigns sponsored by NSF and DOE, which provide intensive in-situ, airborne measurements over the Southern Ocean and ground-based observations at McMurdo station in Antarctica.This project will analyze aircraft-based and ground-based observations over the Southern Ocean and Antarctica, and compare the observations with the Community Earth System Model Version 2 (CESM2) simulations. The focus will be on the observations of ice supersaturation and the relative humidity distribution in mixed-phase and ice clouds, as well as their relationship with cloud micro- and macrophysical properties. Observations will be compared to CESM2 simulations to elucidate model biases. Surface radiation and the precipitation budget at the McMurdo station will be quantified and compared against the CESM2 simulations to improve the fidelity of the representation of Antarctic climate (and climate prediction over Antarctica). Results from our research will be released to the community for improving the understanding of cloud radiative effects and the mass transport of water in the high southern latitudes. Comparisons between the simulations and observations will provide valuable information for improving the next generation CESM model. Two education/outreach projects will be carried out by PI Diao at San Jose State University (SJSU), including a unique undergraduate student research project with hands-on laboratory work on an airborne instrument, and an outreach program that uses social media to broadcast news on polar research to the public.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.