Collaborative Research: Using SOCRATES Datasets to Improve Simulations of Clouds, Aerosols and their Climate Impacts

合作研究：使用 SOCRATES 数据集改进对云、气溶胶及其气候影响的模拟

• 批准号: 1660538
• 负责人: Stephan Fueglistaler
• 金额: $ 23.57万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-15 至 2021-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1660538&HistoricalAwards=false
• 关键词: Collaborative; Research; Using; SOCRATES; Datasets

The Southern Ocean (SO), meaning the global ocean of the high latitude Southern Hemisphere, has a well-deserved reputation as the stormiest place on earth. The remoteness of the SO and its unforgiving conditions have severely limited observations of atmospheric processes occurring above it, including cloud processes in the cyclones traveling along the South Polar front. Yet these processes are of interest for a variety of reasons, including the fact that SO clouds are relatively free from the effects of continental and anthropogenic aerosols, and the region is thus a natural laboratory for the study of cloud behavior under pristine conditions. SO clouds also play a significant cooling role in the energy balance of the planet by reflecting incoming sunlight back to space. There is evidence to suggest that this cooling has a long-range effect on the distribution of the low-latitude rainfall associated with the intertropical convergence zone, and that changes in SO cloudiness due to global climate change will affect the location and strength of the Southern Hemisphere jet stream. One indicator of our lack of understanding of SO cloud processes is the inadequate SO cloud cover found in climate model simulations, which is accompanied by excessive absorption of sunlight by the ocean surface which may in turn cause errors in estimates of climate sensitivity. The deficiency in simulated cloud cover is most pronounced in boundary layer and lower-tropospheric clouds (tops below 3km) in the cold, dry sectors of frontal weather systems traveling along the SO storm track.This project is a component of the Southern Ocean Clouds, Radiation, Aerosol, Transport Experimental Study (SOCRATES). The primary activity of the campaign is the deployment of a Gulfstream V (GV) research aircraft maintained by the Earth Observing Laboratory of the National Center for Atmospheric Research. The GV is based in Hobart, Australia and makes multiple flights across the South Polar front collecting data on SO clouds and the meteorological conditions in which they occur. The GV is equipped with dropsondes to record ambient meteorological conditions, radar and lidar to observe the clouds, and instruments mounted on the wings or positioned behind inlets to to sample, collect and analyze aerosols and cloud particles (liquid droplets and ice crystals). The SOCRATES campaign is complementary to SO activities planned internationally and by other US agencies, including surface observations taken on ships and on MacQuarie Island, a small uninhabited island at 54 degrees South. Work supported here uses data collected in the SOCRATES campaign to improve the representation of SO clouds and cloud-aerosol interactions in climate and weather models. Several possible reasons for the cloud deficiencies are addressed, including deficiencies in the representation of cloud microphysics leading to overly rapid freezing of supercooled liquid water (SLW) cloud droplets, excessive precipitation from shallow cumulus clouds, errors in the representation of small-scale turbulent motions and their effects on the distribution of cloud water, and inaccurate representation of aerosols and their role as condensation nuclei for liquid droplets and nucleating particles for cloud ice. Much of the activity in the campaign is focused on the abundance of SLW in SO clouds, which are less glaciated than their Northern Hemisphere counterparts (i.e. they contain more very cold liquid droplets and fewer ice particles), and work in this project uses model simulations to understand this difference.Two categories of models are used, global atmospheric models and large-eddy simulation (LES) models. Global models include the Community Atmosphere Model version 6 (CAM6), developed by and for the research community and hosted at the National Center for Atmospheric Research, and the Atmospheric Model version 4 (AM4), developed by the Geophysical Fluid Dynamics Laboratory. The LES model is the System for Atmospheric Modeling (SAM), developed by researchers at the State University of New York at Stony Brook and the Colorado State University. For the global models, a "nudged meteorology" strategy is used to facilitate comparisons between observations and model simulations. In this strategy the model is subjected to forcing terms which constrain it to remain close wind and temperature values produced by operational weather forecasting centers. The goal is to reproduce the large-scale meteorological conditions in which campaign observations were made, so that the cloud and aerosol observations from the campaign can be reasonably compared to their simulated counterparts. The project uses the understanding developed from these comparisons, and from the LES modeling, to develop a representation for ice nucleating particles in CAM6. The work has broader impacts due to its potential value for improving models used for weather prediction and future climate projections. The work on model improvement also has broader impacts for the scientific research community, as CAM6 and AM4 are widely used tools for scientific research. The nudged meteorology simulations are available for community use as part of the long-term online archive of data collected in the campaign, along with the meteorological analyses used to nudge the models and ancillary cloud and sea surface observations from satellites. In addition to the broader impacts of the work performed, the project provides support and training for two postdocs, thereby providing for the development of the scientific workforce in this research area. The PIs also contribute to campaign outreach activities including a SOCRATES blog.

南大洋（SO），意为南半球高纬度的全球海洋，被誉为地球上风暴最多的地方，当之无愧。 SO 的偏远及其恶劣的条件严重限制了对其上方发生的大气过程的观测，包括沿南极锋移动的气旋中的云过程。然而，由于多种原因，这些过程引起人们的兴趣，其中包括 SO 云相对不受大陆和人为气溶胶的影响，因此该地区是研究原始条件下云行为的天然实验室。 SO 云还通过将入射阳光反射回太空，在地球的能量平衡中发挥着重要的冷却作用。有证据表明，这种降温对与热带辐合带相关的低纬度降雨分布具有长期影响，并且全球气候变化引起的SO云量变化将影响南半球急流的位置和强度。我们对二氧化硫云过程缺乏了解的一个指标是气候模型模拟中发现二氧化硫云覆盖不足，同时海洋表面过度吸收阳光，进而可能导致气候敏感性估计的错误。模拟云量的不足在沿 SO 风暴路径行进的锋面天气系统的寒冷、干燥区域的边界层和低对流层云（顶部低于 3 公里）中最为明显。该项目是南大洋云、辐射、气溶胶、传输实验研究 (SOCRATES) 的组成部分。该活动的主要活动是部署由国家大气研究中心地球观测实验室维护的湾流 V (GV) 研究飞机。 GV 总部位于澳大利亚霍巴特，多次飞行穿越南极锋线，收集 SO 云及其发生的气象条件的数据。 GV 配备了下投探空仪来记录周围的气象条件，雷达和激光雷达用于观察云层，以及安装在机翼上或位于入口后面的仪器来采样、收集和分析气溶胶和云颗粒（液滴和冰晶）。 SOCRATES 活动是对国际上和其他美国机构计划的 SO 活动的补充，包括在船舶上和在麦夸里岛（南纬 54 度的一个无人居住的小岛）上进行的表面观测。这里支持的工作使用 SOCRATES 活动中收集的数据来改善气候和天气模型中 SO 云和云-气溶胶相互作用的表示。解决了云缺陷的几个可能原因，包括云微物理表示的缺陷导致过冷液态水（SLW）云滴过快冻结、浅层积云过度降水、小尺度湍流运动表示错误及其对云水分布的影响、气溶胶表示不准确及其作为液体凝结核的作用 云冰的液滴和成核粒子。 该活动的大部分活动都集中在SO云中SLW的丰度上，SO云中的冰川比北半球的云少（即它们含有更多的极冷液滴和更少的冰颗粒），并且该项目中的工作使用模型模拟来理解这种差异。使用了两类模型，全球大气模型和大涡模拟（LES）模型。 全球模型包括社区大气模型第 6 版 (CAM6)，由研究界开发并由国家大气研究中心托管，以及大气模型第 4 版 (AM4)，由地球物理流体动力学实验室开发。 LES 模型是大气建模系统 (SAM)，由纽约州立大学石溪分校和科罗拉多州立大学的研究人员开发。 对于全球模型，使用“推动气象学”策略来促进观测和模型模拟之间的比较。 在该策略中，模型受到强制条件的影响，限制其保持接近运行天气预报中心产生的风和温度值。 目标是重现进行活动观测时的大范围气象条件，以便活动中的云和气溶胶观测结果可以与模拟观测结果进行合理比较。 该项目利用从这些比较和 LES 建模中获得的理解，开发 CAM6 中冰成核粒子的表示。这项工作具有更广泛的影响，因为它对于改进天气预报和未来气候预测模型具有潜在价值。 模型改进工作也对科学研究界产生更广泛的影响，因为 CAM6 和 AM4 是广泛使用的科学研究工具。 推动的气象模拟可供社区使用，作为活动中收集的数据长期在线存档的一部分，以及用于推动模型和卫星辅助云和海面观测的气象分析。除了所开展的工作产生更广泛的影响外，该项目还为两名博士后提供支持和培训，从而促进该研究领域科学队伍的发展。 PI 还为包括苏格拉底博客在内的竞选外展活动做出贡献。

项目成果

Reduction of Bias from Parameter Variance in Geophysical Data Estimation: Method and Application to Ice Water Content and Sedimentation Flux Estimated from Lidar

减少地球物理数据估算中参数方差的偏差：激光雷达估算冰水含量和沉积通量的方法及应用

• DOI: 10.1175/jas-d-19-0106.1
• 发表时间: 2020
• 期刊: Journal of the Atmospheric Sciences
• 影响因子: 3.1
• 作者: Bolot, Maximilien;Fueglistaler, Stephan
• 通讯作者: Fueglistaler, Stephan

Tropical Water Fluxes Dominated by Deep Convection Up to Near Tropopause Levels

热带水通量由深对流主导直至接近对流层顶水平

• DOI: 10.1029/2020gl091471
• 发表时间: 2021
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Bolot, Maximilien;Fueglistaler, Stephan
• 通讯作者: Fueglistaler, Stephan

Simple Spectral Models for Atmospheric Radiative Cooling

大气辐射冷却的简单光谱模型

• DOI: 10.1175/jas-d-18-0347.1
• 发表时间: 2020
• 期刊: Journal of the atmospheric sciences
• 影响因子: 3.1
• 作者: Jeevanjee, Nadir;Fueglistaler, Stephan
• 通讯作者: Fueglistaler, Stephan