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

该项目探讨了热带潮汐在季节内或马登-朱利安涛动(MJO，约30-60天)和厄尔尼诺-南方涛动(ENSO，约2-10年)时间尺度上的变化。低纬中频(MF)雷达测风表明，日潮汐幅度在季节内(IS)和年际时间尺度上受到调制。传播的日潮是热带对流层和高层大气之间耦合的一个很强的因素。因此，如果对流层全日潮汐的强迫在MJO和ENSO时间尺度上经历系统的大尺度变化，这种变化可能会通过潮汐在低纬的垂直传播传递到高层大气中。考艾岛(北纬22度，西经159度)和拉罗通加(S度22度，西经160度)的热带雷达在赤道附近具有几乎完美的对称性。这些是监测日潮汐结构和时间变化的关键位置，因为它们位于潮汐风幅最大的纬度附近。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，这一支助将使雷达能够在定时任务期间持续、可靠地运作，并增强能力。

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.