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

本项目研究在季节内或马登-朱利安振荡（MJO，约30-60天）和厄尔尼诺-南方涛动（ENSO，约2-10年）的时间尺度上中层热带日潮的变化。 低纬度中频（MF）雷达风测量表明，昼夜潮汐振幅在季节内（IS）和年际时间尺度上受到调制。 日潮的传播是热带对流层和高层大气之间强耦合的媒介。 因此，如果对流层日潮汐的强迫在MJO和ENSO时间尺度上经历系统的、大尺度的变化，这种变化可能通过潮汐在低纬度的垂直传播而传递到高层大气。拉罗汤加（南纬22度，西经160度）和拉罗汤加（南纬22度，西经159度）的地理位置独特，几乎完美地对称于赤道。 这些是监测昼夜潮汐结构和时间变化的关键位置，因为它们靠近潮汐风振幅最大的纬度。 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。 业务支助包括维护、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使命期间连续、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.