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Collaborative Research: Cirrus Cloud Formation and Microphysical Properties from In-situ Observed Characteristics to Global Climate Impacts

合作研究：从现场观测特征到全球气候影响的卷云形成和微物理特性

基本信息

批准号：
1642291
负责人：
Minghui Diao
金额：
$ 33.89万
依托单位：
San Jose State University Foundation
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2017
资助国家：
美国
起止时间：
2017-08-15 至 2022-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1642291&HistoricalAwards=false
关键词：
Collaborative Research Cirrus Cloud Formation

项目摘要

This study will investigate the determinant factors behind cirrus cloud formation and evolution based on in-situ observations at various geographical locations. In addition, the global radiative forcing of observation-constrained aerosol impacts on cirrus microphysical properties will be quantified by using a climate model. The project will focus on three critical scientific issues: (1) Hemispheric differences in cirrus cloud macroscopic and microphysical properties under similar dynamical conditions; (2) Multi-scale dynamical forcings driving ice nucleation and their impacts on cirrus simulations in a climate model; and (3) Impacts of anthropogenic aerosol emissions on cirrus microphysical properties and the subsequent influences on global radiation.To address these scientific issues, The research team will: (1) extract cirrus cloud samples from a composite in-situ dataset covering various geographical locations, and compare the formation and evolution of cirrus clouds between two hemispheres; (2) examine the micro- to mesoscale (~0.1-10 km) variabilities of water vapor and temperature, and improve the NCAR Community Atmosphere Model version 5 (CAM5) by including these observed variabilities; (3) compare the in-situ measured cirrus microphysical properties between polluted and pristine regions, and use CAM5 to quantify the consequent perturbations on global radiation balance.Intellectual Merit:Cirrus clouds are one of the main modulators of Earth's climate system. However, due to their large spatial heterogeneity and temporal variability, cirrus clouds remain one of the poorly-represented components in current general circulation models (GCMs). This project will improve our understanding of cirrus microphysical properties in relation to dynamical conditions and aerosol backgrounds, by analyzing in-situ aircraft data obtained from both the Northern and Southern Hemispheres, polluted and pristine regions. Furthermore, the research team will use the observed characteristics to evaluate the simulations of relative humidity and cirrus clouds in CAM5 in terms of their occurrence, spatial coverage and microphysical properties. In addition, a "best-observation-matched" ice microphysics configuration will be implemented into CAM5. Overall, using micro- to mesoscale observations of cirrus formation and evolution, the research will improve cirrus cloud simulations in CAM5 and provide a new estimation on cirrus clouds' adjustments due to anthropogenic aerosol emissions (i.e., aerosol indirect forcing through perturbations of cirrus microphysical properties).Broader Impacts:Both the observational dataset and the new model parameterization will be released to the community, including a synthesized in-situ observation dataset (a total of 8 campaigns from NSF, NASA and European Union), and a sub-grid scale parameterization of relative humidity variability for GCMs. The improved estimation of anthropogenic aerosol impact on cirrus cloud radiative forcing can contribute to uncertainty reduction in the next IPCC report. The project will greatly benefit teaching and mentoring of undergraduate and graduate students at University of Wyoming and San Jose State University. The project will also recruit and train undergraduate students for presenting their research at the local K-12 schools via San Jose State University's undergraduate Ambassador Program.

本研究将基于不同地理位置的现场观测，探讨卷云形成和演变的决定因素。此外，将使用气候模式量化观测受限气溶胶对卷云微物理特性影响的全球辐射强迫。该项目将重点研究三个关键科学问题：(1)相似动力条件下卷云宏观和微物理特性的半球差异；(2)气候模式下驱动冰成核的多尺度动力强迫及其对卷云模拟的影响；(3)人为气溶胶排放对卷云微物理特性的影响及其对全球辐射的影响。为了解决这些科学问题，研究团队将：(1)从覆盖不同地理位置的复合原位数据集中提取卷云样本，并比较两个半球之间卷云的形成和演变；(2)研究水汽和温度的微中尺度（~0.1 ~ 10 km）变化，并对NCAR群落大气模式第5版（CAM5）进行改进；(3)比较污染地区和原始地区的原位测量卷云微物理特性，并利用CAM5量化其对全球辐射平衡的扰动。知识价值：卷云是地球气候系统的主要调节器之一。然而，由于其巨大的空间异质性和时间变异性，卷云仍然是当前大气环流模式（GCMs）中代表性较差的成分之一。该项目将通过分析从北半球和南半球、污染地区和原始地区获得的现场飞机数据，提高我们对卷云微物理特性与动力条件和气溶胶背景的理解。此外，研究小组将利用观测到的特征，对CAM5中相对湿度和卷云的发生、空间覆盖和微物理特性的模拟进行评估。此外，CAM5将实现“最佳观测匹配”冰微物理配置。总体而言，通过对卷云形成和演化的微到中尺度观测，本研究将改进CAM5中的卷云模拟，并对人为气溶胶排放（即气溶胶通过扰动卷云微物理特性间接强迫）导致的卷云调整提供新的估计。更广泛的影响：观测数据集和新模式参数化将向社区发布，包括一个综合的原位观测数据集（来自NSF、NASA和欧盟的总共8个活动），以及一个gcm相对湿度变率的亚网格尺度参数化。对人为气溶胶对卷云辐射强迫影响的改进估计有助于减少IPCC下一份报告的不确定性。该项目将大大有利于怀俄明大学和圣何塞州立大学本科生和研究生的教学和指导。该项目还将通过圣何塞州立大学的本科生大使计划招募和培训本科生，在当地K-12学校展示他们的研究成果。