CEDAR: Intraseasonal and Interannual Variations in Diurnal Tropospheric Heating and in Mesospheric and Lower Thermospheric Tides

本项目在季节内或马登-朱利安涛动（MJO，约30-60天）和厄尔尼诺-南方涛动（ENSO，约2-10年）的时间尺度上研究热带中层日潮的变化。低纬度中频（MF）雷达风测量表明，日潮汐幅值在季节内（IS）和年际时间尺度上被调制。传播的日潮是热带对流层和高层大气之间耦合的一个强因子。因此，如果对流层日潮的强迫在MJO和ENSO时间尺度上经历系统的大尺度变化，这种变化可能通过低纬度潮汐的垂直传播传递到高层大气。考艾岛（北纬22度，西经159度）和拉罗汤加岛（南纬22度，西经160度）的热带雷达位于赤道周围，几乎完全对称。这些是监测日潮结构和时间变化的关键位置，因为它们靠近潮汐风幅值最大的纬度。除了支持潮汐变化的科学分析外，该项目还将为热带雷达提供业务支持。业务支持包括维护、系统升级、小修和数据存档。我们预计，这种支持将使雷达能够在TIMED任务期间连续、可靠地运行，并具有增强的能力。

This project addresses variability of the tropical diurnal tide in the mesosphere on timescales of the intraseasonal, or Madden-Julian Oscillation (MJO, approximately 30-60 days) and the El Nino-Southern Oscillation (ENSO, approximately 2-10 years). Low-latitude medium frequency (MF) radar wind measurements suggest that diurnal tide amplitudes are modulated on intraseasonal (IS) and interannual time scales. The propagating diurnal tides are a strong agent of coupling between the tropical troposphere and the upper atmosphere. Thus, if the forcing of tropospheric diurnal tides undergoes systematic, large-scale variations on MJO and ENSO time scales, such variability may be transmitted into the upper atmosphere by means of the tide's vertical propagation at low latitudes.The tropical radars at Kauai (22 degrees N, 159 degrees W) and at Rarotonga (22 degrees S, and 160 degrees W) are uniquely situated with almost perfect symmetry around the equator. These are key locations for monitoring the structure and temporal variability of the diurnal tide, since they are near the latitude where the tidal wind amplitude maximizes. In addition to supporting scientific analyses of tidal variability, this project will provide operational support for the tropical radars. The operational support includes maintenance, system upgrades, minor repairs and data archival. We anticipate that this support would allow the radars to operate continuously, reliably and with enhanced capability for the duration of the TIMED mission.