SGER: New Approaches for the Measurement of Microphysics in Extratropical Hurricanes

这是一笔小额赠款，用于探索性研究，以支持加勒特博士参与2003年秋季的飓风实验(ETHEX)的温带过渡。ETHEX的目标是观察大西洋飓风从热带向北移动并演变为具有中纬度气旋特征的特征。这样的风暴往往规模大、强度大，可能会造成暴雨、洪水、财产损失和生命损失。作为ETHEX的一部分，由加拿大国家研究委员会和加拿大气象局联合运营的Convair 580研究飞机将进行风暴穿透飞行，以测量起源于飓风的中纬度风暴的微物理特性。测量包括水滴的大小分布，单位体积的云水和冰量，以及冰晶的大小和形状。加勒特博士将在飞机上安装云积分浊度计(CIN)，这是Gerber Science公司制造的一种仪器，用于测量云的某些体积积分光学属性，特别是消光系数和不对称参数，非对称参数是衡量前向散射相对于总散射的重要性的指标。该参数对于冰云的值与对于水云的值不同。CIN通过不对称参数提供混合相云中存在的冰的比例的直接测量，从而为ETHEX的目标做出贡献。这是以其他方式无法获得的重要信息，既可以描述云的微物理结构，也可以帮助解释其他仪器的测量结果，这些仪器并不总是能够区分水和冰。CIN提供的独立消光测量也有助于验证其他仪器对液滴尺寸分布的测量。该项目的更广泛影响包括提高建模和预测温带飓风的能力，以及鼓励美国和加拿大云物理学家的合作。

This is a Small Grant for Exploratory Research to support the participation of Dr. Garrett in the Extratropical Transition of Hurricanes Experiment (ETHEX) in the fall of 2003. The objective of ETHEX is to observe the characteristics of Atlantic hurricanes as they move north from the tropics and evolve to take on the characteristics of midlatitude cyclones. Such storms are often large and intense, and can cause heavy rain, flooding, property damage, and loss of life. As part of ETHEX, the Convair 580 research aircraft operated jointly by the National Research Council of Canada and the Canadian Meteorological Service will make storm-penetration flights to measure the microphysical properties of midlatitude storms that originated as hurricanes. The measurements include drop-size distributions, the amounts of cloud water and ice per unit volume, and ice crystal sizes and shapes. Dr. Garrett will install on the airplane a Cloud Integrating Nephelometer (CIN), an instrument built by Gerber Scientific for measuring certain volume-integrated optical properties of clouds, specifically the extinction coefficient and the asymmetry parameter, a measure of the importance of forward scattering compared with the total scattering. This parameter has a different value for ice clouds than for water clouds. The CIN contributes to the objectives of ETHEX by providing, through the asymmetry parameter, a direct measure of the proportion of ice present in mixed-phase clouds. This is important information, not otherwise obtainable, both for characterizing the microphysical structure of the clouds and for helping to interpret the measurements of other instruments, which are not always able to distinguish between water and ice. The independent measurement of extinction that the CIN provides also helps to validate the measurements of drop-size distribution by the other instruments. Broader impacts of the project include improving the ability to model and forecast extratropical hurricanes and encouraging the collaboration of American and Canadian cloud physicists.