High Latitude Dynamical Studies Using Radar and Satellite Observations

调查人员将观测、模拟和研究中部大气半日潮的时空结构和变异。重点将放在北极和南极的中间层和低层热层水平风和温度场上。中层和低层热层位于地球表面以上80至120公里的高度，是低层大气（对流层/平流层）与高层大气热层/电离层耦合的高度动态区域。在这个区域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输送到高层大气。近年来的研究表明，高纬度（北极和南极）的中间层和低层热层拥有丰富的行星波谱，这是以前未被发现的。这些行星波可以与太阳同步迁移的半日潮相互作用，改变其时空结构，同时产生非迁移的半日潮。了解半日潮的结构和变率是了解全球中层和低层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一个由30个地面流星和中频雷达组成的全球网络的水平风测量。此外，来自NASA TIMED卫星的风和温度测量将与雷达数据相结合。根据以前的观测，预计行星波将在半日潮的变化中起重要作用。因此，将同时估计半日潮的结构和行星波的结构。将结合线性机制模式和全球环流模式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认识。作为这项工作的一部分，将采用基于网络的工具从全球网络中获取雷达数据。提交给数据库的数据将经过处理，然后通过一个网站、计时数据库和雪松数据库传播。这样一个数据库对于现在和将来打算利用全球中间层和低层热层雷达风测量网的工作是必需的。

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.