Connecting Small-scale Humidity Variability to Dynamical Processes Governing Madden-Julian Oscillation Transitions

将小尺度湿度变化与控制 Madden-Julian 振荡转变的动态过程联系起来

• 批准号: 1321891
• 负责人: Paquita Zuidema
• 金额: $ 31.88万
• 依托单位: University of Miami
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-15 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1321891&HistoricalAwards=false
• 关键词: Connecting; Small; scale; Humidity; Variability

This project studies the role of low-level atmospheric moisture in the development of convective clouds associated with the Madden-Julian Oscillation (MJO). The MJO is an envelope of organized convection that propagates from the Indian Ocean to the Pacific Ocean and constitutes the dominant form of intraseasonal precipitation variability in the tropics, and also has important consequences for US weather. The present work is a follow-on to the Dynamics of the MJO (DYNAMO) field campaign, which took place in the equatorial Indian Ocean in 2011-2012 and involved the deployment of radars and other observing assets on Gan Island in the Maldives. One hypothesis of the campaign, also pursued in this project, is that the deep, organized convective clouds associated with MJO initiation develop only when the atmospheric boundary layer, which contains most of the moisture in the atmospheric column, becomes sufficiently deep over a sufficiently large region. The primary task of the present work is to generate humidity datasets using radar and scanning radiometer data collected as part of the campaign, through techniques involving 1) the Bragg scattering of S-band radar signals in cloud-free air; and 2) a combination of radiometer data and the differential attenuation of radar returns from clouds at two wavelengths (S- and Ka-band in this case). The analysis of these humidity products will be complemented by numerical experiments carried out with the Weather Research and Forecasting (WRF) model.The work has broader scientific impacts due to the value new techniques for determining humidity, particularly techniques that can be applied in future field campaigns, as well as the value of the new humidity datasets for the research community. In addition, the work seeks a better understanding of the initiation of MJO, which would be of societal value to the extent that it results in better predictions of the MJO and its downstream consequences. In addition, the work has an educational component, including the use of the datasets in classroom teaching and the support of two graduate students.

该项目研究低层大气湿度在与马登-朱利安振荡 (MJO) 相关的对流云发展中的作用。 MJO 是有组织对流的包络线，从印度洋传播到太平洋，构成热带地区季节内降水变化的主要形式，并对美国天气产生重要影响。 目前的工作是 MJO (DYNAMO) 动力实地活动的后续工作，该活动于 2011 年至 2012 年在赤道印度洋进行，涉及在马尔代夫甘岛部署雷达和其他观测资产。 该活动的一个假设（也是本项目所追求的）是，只有当大气边界层（包含大气柱中的大部分水分）在足够大的范围内变得足够深时，与 MJO 启动相关的深层、有组织的对流云才会形成。地区。 目前工作的主要任务是使用作为活动一部分收集的雷达和扫描辐射计数据来生成湿度数据集，通过涉及以下技术：1）无云空气中 S 波段雷达信号的布拉格散射； 2) 辐射计数据和两个波长（本例中为 S 和 Ka 波段）的云雷达回波的差分衰减的组合。 对这些湿度产品的分析将得到利用天气研究和预报 (WRF) 模型进行的数值实验的补充。由于确定湿度的新技术的价值，特别是可在未来领域应用的技术，这项工作具有更广泛的科学影响活动，以及新湿度数据集对研究界的价值。 此外，这项工作旨在更好地理解 MJO 的启动，这将具有社会价值，因为它可以更好地预测 MJO 及其下游后果。 此外，这项工作还具有教育意义，包括在课堂教学中使用数据集以及两名研究生的支持。