Modeling Satellite Correlations of Aerosol Optical Depth Versus Cloud Optical Depth Over Megacities

对大城市上空气溶胶光学深度与云光学深度的卫星相关性进行建模

• 批准号: 1441062
• 负责人: Mark Jacobson
• 金额: $ 46.02万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-01 至 2019-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1441062&HistoricalAwards=false
• 关键词: Modeling; Satellite; Correlations; Aerosol; Optical

This project seeks to gain a better understanding of aerosol/cloud interactions and the effects of these on global temperatures. The research is based on investigating satellite measurements of the thickness of aerosols (small particles) and clouds in the atmosphere over several global megacities. Data from a prior study over 2 megacities suggest that as the thickness of aerosols increases in the atmosphere, the density of clouds tends also to increase to a point, but then begins to decrease. Since satellite data can show correlations but not cause and effect, and models can show cause/effect, a computer model will be used in this project to simulate the relationship between clouds and aerosols over three megacities. The results will help to improve the ability of computer models to predict global climate change.This research focuses on the investigating satellite measurements of aerosol optical depth (AOD) and cloud optical depth (COD) over several megacities to assess the relative importance of different types of aerosol feedbacks on clouds. Previously a boomerang curve was identified (an increase then a decrease of COD with increasing AOD) where the increase in COD at low AOD is believed to be due to microphysical (indirect) effects and a decrease in COD at high AOD is thought to be due to radiative effects (cloud absorption effects and the semidirect effect).The project consists of three tasks: 1) complete the satellite retrieval worked performed for the first part of the project over one more megacity region, New Delhi India; 2) use a nested global-through-local 3-D model (GATOR-GCMOM) to determine whether the boomerang curves found in the satellite data can be attributed to absorbing aerosols; and 3) run a 24-year global baseline simulation and sensitivity simulations examining the separate effects of fossil-fuel soot, solid biofuel soot and gases, biomass burning soot and gases, methane, and all anthropogenic components on global climate, accounting for indirect effects, semi-direct effect, and the cloud absorption effect. To evaluate the significance of the model results, a two-sided t-test for unequal sample sizes of unequal variance will be used to determine whether the computer modeled difference in a given parameter between a baseline simulation and a sensitivity simulation is statistically significant relative to chaotic variation in a climate model.

该项目旨在更好地了解气溶胶/云相互作用以及这些相互作用对全球温度的影响。该研究基于研究卫星测量气溶胶（小颗粒）的厚度（小颗粒）和大气中几种全球大城市的云。先前研究的数据超过2个大城市表明，随着气溶胶的厚度在大气中的增加，云的密度也倾向于增加到某个点，但随后开始降低。由于卫星数据可以显示相关性，但不能显示原因和效果，并且模型可以显示原因/效果，因此该项目中将使用计算机模型来模拟三个大兆含量的云与气溶胶之间的关系。结果将有助于提高计算机模型预测全球气候变化的能力。本研究的重点是调查气溶胶光学深度（AOD）和云光学深度（COD）的卫星测量值，以评估云上不同类型的Aerosol反馈的相对重要性。以前鉴定出Boomerang曲线（与AOD增加的COD降低相比，低于AOD的降低）认为，低AOD处的COD的增加被认为是微物理（间接）效应引起的，并且高AOD处的COD降低被认为是由于辐射效应是由于辐射效应（云吸收效应和半偏射效应）。新德里印度更多的大型地区； 2）使用嵌套的全球直通局部3-D模型（Gator-GCMOM）来确定在卫星数据中发现的回旋镖曲线是否可以归因于吸收气溶胶； 3）运行24年的全球基线模拟和灵敏度模拟，研究了化石燃料烟灰，固体生物燃料烟灰和气体的独立影响，生物质燃烧的烟灰和气体，甲烷以及所有人为成分对全球气候，对间接影响，半独立效应和云吸收效果的核算，对全球气候的核算。为了评估模型结果的重要性，将使用不平等差异样本大小的两侧t检验来确定基线模拟和灵敏度模拟之间给定参数的计算机建模差异是否相对于气候模型中的混乱变化具有统计学意义。