High Latitude Dynamical Studies Using Radar and Satellite Observations

调查人员将观测、模拟和研究中层大气半日潮的时空结构和变化。重点将放在北极和南极的中间层和低热层的水平风场和温度场。中间层和低热层位于地球表面上方80至120公里的高度，是一个高度动态的区域，将低层大气（对流层/平流层）与高层大气（热层/电离层）耦合在一起。在这一地区特别重要的是向上传播的热强迫大气潮汐和全球尺度的行星波。这两种现象都将热量和动量从低层大气传输到高层大气。近年来的研究表明，高纬度（北极和南极）的中间层和低热层拥有丰富的行星波谱，这在以前是未被发现的。这些行星波可以与太阳同步迁移半日潮相互作用，改变其时空结构，同时产生非迁移半日潮。了解半日潮的结构和变化是了解全球中层和低热层热量和能量平衡的重要一步。该项目使用的数据将包括来自30个地面流星和中频雷达全球网络的水平风测量数据。此外，来自NASA TIMED卫星的风和温度测量结果将与雷达数据相结合。从以前的观测结果可以预计，行星波将在半日潮的变化中发挥重要作用。由于这个原因，半日潮的结构和行星波的结构将同时估计。将结合线性机械模型和全球环流模型对这些估计进行分析，以帮助解释观测结果，并增加对半日潮的了解。作为这项工作的一部分，将采用一种基于网络的工具，从全球网络获取雷达数据。提交给数据库的数据将经过处理，然后通过一个网站、TIMED数据库和CEDAR数据库传播。这一数据库是目前和今后拟议利用全球中间层和低热层雷达测风网络的努力所必需的。

The investigators will observe, model and study the spatial-temporal structure and variability of the semidiurnal tide in the middle atmosphere. The focus will be on the Arctic and Antarctic mesosphere and lower thermosphere horizontal wind and temperature fields. The mesosphere and lower thermosphere, at an altitude between 80 and 120km above the surface of the earth, is a highly dynamic region that couples the lower atmosphere (troposphere/stratosphere) with the upper atmosphere thermosphere/ionosphere). Of particular importance in this region are both the upward propagating thermally forced atmospheric tides and global scale planetary waves. Both of these phenomena transport heat and momentum from the lower atmosphere into the upper atmosphere. Studies in recent years have indicated that the high latitude (Arctic and Antarctic) mesosphere and lower thermosphere possess a rich spectrum of planetary waves that had previously gone undiscovered. These planetary waves can interact with the sun-synchronous migrating semidiurnal tide modifying its spatial and temporal structure while giving rise to the nonmigrating semidiurnal tide. Understanding the structure and variability of the semidiurnal tide is an important step to understanding the global heat and energy balance of the mesosphere and lower thermosphere. The data used for this project will include horizontal wind measurements from a global network of 30 ground-based meteor and medium frequency radars. Additionally, wind and temperature measurements from the NASA TIMED satellite will be combined with the radar data. It is expected, from previous observations, that planetary waves will play a significant role in the variability of the semidiurnal tide. For this reason the structure of the semidiurnal tide and the structure of the planetary waves will be estimated simultaneously. These estimates will be analyzed in conjunction with both linear mechanistic and global circulation models to aid in the interpretation of the observations and increase knowledge about the semidiurnal tide. As part of this effort a web based tool to ingest the radar data from the global network will be employed. Data submitted to the database will be processed and then disseminated via a website, the TIMED database and the CEDAR database. Such a database is required for this and future efforts that propose to make use of the global network of mesosphere and lower-thermosphere radar wind measurements.