Characteristics of Cloud-Nucleating Aerosols and Their Effects on Cloud Microphysical and Radiative Properties in INDOEX

INDOEX 云成核气溶胶特征及其对云微物理和辐射特性的影响

• 批准号: 9906903
• 负责人: Cynthia Twohy
• 金额: $ 19.78万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-08-01 至 2003-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9906903&HistoricalAwards=false
• 关键词: Characteristics; Cloud; Nucleating; Aerosols; Their

This project is aimed at understanding how aerosol particles affect cloud radiative properties through changes in droplet number concentration and size (the so-called "indirect" effect). It will employ observations of the physical and chemical properties of aerosols obtained with airborne instruments during the Indian Ocean Experiment (INDOEX). Optical particle counters, cloud condensation nucleus spectrometers, and electron microscope analysis are the principal means of analyzing the aerosol properties. Characteristics of particles sampled both below and above clouds will be compared with residual nuclei extracted from cloud droplets to assess which particles act as cloud condensation nuclei. In particular, the relative importance of sulfate, sea-salt, soil-dust, and elemental carbon will be evaluated. The critical supersaturation spectra of the ambient particles and residual nuclei will be compared as well. Through a series of case studies, the principal investigator will determine whether in-cloud aerosol follow an expected simple adiabatic relationship, that is, the particles with the lowest critical supersaturation preferentially nucleate cloud droplets. Air trajectories and aerosol chemical measurements will be used to determine the specific role of anthropogenic aerosols in affecting cloud properties. Variations in thermodynamic, aerosol, microphysical, and cloud radiative parameters will be studied via multivariate techniques in order to ascertain parameter dependence and to help separate aerosol effects from dynamic effects on clouds. Support for this project is shared by the Atmospheric Chemistry and Physical Meteorology Programs and the Water and Energy: Atmospheric, Vegetative and Earth Interactions (WEAVE) Initiative of the Global Change Program.

该项目旨在了解气溶胶粒子如何通过改变液滴的数量、浓度和大小(所谓的“间接”效应)影响云层的辐射特性。它将使用在印度洋实验(INDOEX)期间使用机载仪器获得的气溶胶的物理和化学性质的观测。光学粒子计数器、云凝聚核谱仪和电子显微镜分析是分析气溶胶性质的主要手段。云下和云上采样的粒子的特征将与从云滴中提取的残余核进行比较，以评估哪些粒子充当云凝结核。特别是，将评估硫酸盐、海盐、土壤灰尘和元素碳的相对重要性。还将比较周围粒子和剩余核的临界过饱和度光谱。通过一系列的案例研究，首席研究人员将确定云内气溶胶是否遵循预期的简单绝热关系，即临界过饱和度最低的粒子优先成核云滴。将使用空气轨迹和气溶胶化学测量来确定人为气溶胶在影响云特性方面的具体作用。将通过多变量技术研究热力学、气溶胶、微物理和云辐射参数的变化，以确定参数相关性，并帮助区分气溶胶效应和云的动力效应。对该项目的支持由大气化学和物理气象计划以及全球变化计划的水和能源：大气、植物和地球相互作用(Weave)倡议共同提供。