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Tropical/Extratropical Interaction Mechanisms at the Intraseasonal Time Scale

季节内时间尺度的热带/温带相互作用机制

基本信息

批准号：
1822015
负责人：
Steven Feldstein
金额：
$ 61.35万
依托单位：
Pennsylvania State Univ University Park
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2018
资助国家：
美国
起止时间：
2018-07-01 至 2022-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1822015&HistoricalAwards=false
关键词：
Tropical Extratropical Interaction Mechanisms Intraseasonal

项目摘要

This project has the potential to lead to an improvement of the subseasonal (2-6 week) probabilistic weather forecasts of temperature and precipitation for North America. Support for this outcome is based upon the previous research by the team on the influence of tropical weather on mid-latitude weather, which has contributed to the development of the probabilistic subseasonal weather forecast method used by NOAA. This project will also train a graduate student to become an independent scientist. Besides participating in the usual activities of publishing papers and giving conference presentations, the team will work with personnel at Penn State's Center for Science and the Schools to conduct a five-day workshop on subseasonal to seasonal (S2S) prediction for middle and high school teachers from low socioeconomic and racially diverse urban and rural Pennsylvania school districts that serve populations highly underrepresented in science, technology, engineering, and math fields. The teachers will attend lectures on the techniques used for S2S forecasting, and participate in relevant inquiry-based activities. The team will provide follow-up support as the teachers implement the workshop activities in their classrooms.In the tropics, the dominant pattern on the intraseasonal time scale, the Madden-Julian Oscillation (MJO), is characterized by organized precipitation systems that propagate eastward encircling the tropics on a timescale of 30-70 days. The importance of the MJO for forecasting is evidenced by the use of the state of the MJO in week-3 and week-4 probabilistic forecasts by the NOAA/Climate Prediction Center. Although much progress has been made during the past three decades toward understanding how tropical convective heating influences the weather in mid-latitudes, there are still important unaddressed questions. This project will focus on questions that have not yet been investigated or have received little previous attention: (1)investigation of how Rossby waves are excited by MJO-related convection in the tropics propagate pole-ward,and impact weather in the mid-latitudes; (2) variation in the horizontal and vertical structure of the latent heat released in convections within the MJO event, and its impact in a key region, the central subtropical North Pacific; and (3) role of inertio-gravity waves excited by MJO-related convections in connecting tropical convections to weather over large distances across the Earth, e.g., teleconnection patterns. The team will also address the following questions: Why does the high latitude component within teleconnection patterns persist for a much longer time period than do their lower latitude counterparts? What is the impact of inertio-gravity waves excited by the MJO on mid-latitude weather? The topic is particularly important because active teleconnection patterns have a large influence on the weather up to 6 weeks later. The approach includes the use of observational datasets and computer model calculations. The computer model will be used to isolate and to better understand the key physical processes that are responsible for the tropical-extratropical teleconnections.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

该项目有可能改善北美亚季节性(2-6周)气温和降水的概率天气预报。对这一结果的支持是基于该团队之前关于热带天气对中纬度天气的影响的研究，这有助于开发美国国家海洋和大气局使用的概率亚季节天气预报方法。该项目还将培养一名研究生成为一名独立的科学家。除了参与发表论文和发表会议演讲的常规活动外，该团队还将与宾夕法尼亚州立大学科学中心和学校的人员合作，为来自社会经济水平较低、种族多元化的宾夕法尼亚州学区的初中和高中教师举办为期五天的亚季节性到季节性(S2S)预测研讨会，这些学区服务于科学、技术、工程和数学领域代表性严重不足的人群。教师将参加有关S2S预测技术的讲座，并参加相关的探究式活动。该小组将在教师在课堂上开展讲习班活动时提供后续支持。在热带地区，季节内时间尺度上的主导模式--马登-朱利安涛动(MJO)，其特点是有组织的降水系统以30-70天的时间尺度向东传播，环绕热带。海洋和大气层管理局/气候预测中心使用MJO在第3周和第4周的概率预报证明了MJO对预报的重要性。尽管在过去30年里，在了解热带对流加热如何影响中纬度天气方面取得了很大进展，但仍有一些重要的问题尚未解决。这个项目将集中于尚未被研究或以前很少受到关注的问题：(1)热带与MJO有关的对流激发Rossby波如何向极地传播并影响中纬度天气；(2)MJO事件内对流中释放的潜热的水平和垂直结构的变化及其对关键区域--中央副热带北太平洋的影响；(3)由与MJO有关的对流激发的惯性重力波在连接热带对流与地球上大距离天气中的作用，例如远程连接模式。该团队还将解决以下问题：为什么遥相关模式中的高纬度分量比低纬度分量持续更长的时间？MJO激发的惯性重力波对中纬度天气有何影响？这个话题特别重要，因为活跃的遥相关模式对6周后的天气有很大影响。该方法包括使用观测数据集和计算机模型计算。计算机模型将被用来隔离和更好地理解导致热带-温带遥相关的关键物理过程。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。