Collaborative Research: Jicamarca Radar Studies of Gravity Waves from D Region to Lower F Region

这项工作将利用秘鲁希卡马卡的50兆赫雷达，从大约60至170公里的高度观测赤道中层和低热层的高频重力波。该雷达将用于现有MST-ISR模式的扩展。除了发射长脉冲和编码脉冲用于隔行探测中间层回波和电离层非相干散射雷达回波（所谓的MST和ISR信号）外，还将发射短脉冲和未编码脉冲，以高时间和空间分辨率探测湍流赤道电射流高度区（E区本身）。将利用电射流产生的短脉冲数据提供赤道E区的重力波特征，以补充在MST-ISR模式下获得的D区和E区上部（140公里以上）重力波数据。总体目标是增进目前对重力波在赤道中间层和低热层中传播和引导的了解，以及重力波通过中性和等离子体不稳定过程在该区域结构中的作用。重力波在大气区域的动力耦合中起着至关重要的作用。向上传播通过中间层和低热层的波（或可能作为二次波产生的波）可能在电离层的E和F区域中增长到显著的振幅。Jicamarca雷达的快速连续采样提供了关于低纬度中性大气的短期（5-15分钟）重力波振荡和不稳定性的重要信息。短周期波总是存在于赤道中层，这在Jicamarca垂直风数据中很明显，在赤道上E区也很明显，这在Jicamarca观测到的150公里高度区域的后向散射增强中很明显。这些波系统之间的联系及其与介于E区高度之间的重力波的关系仍然是未知和未探索的。在Jicamarca上方，这一区域被湍流赤道电射流（EEJ）占据，造成强烈的雷达后向散射。这种后向散射信号的调制将被用于对该区域的重力波内容及其与在中间层和上E区观测到的重力波的关系进行新的研究。

The work will use the 50 MHz radar at Jicamarca, Peru to observe high-frequency gravity waves in the equatorial mesosphere and lower thermosphere from about 60 to 170 km. The radar will be used in an extension of an existing MST-ISR mode. Besides transmitting long and coded pulses for interlaced detection of mesospheric echoes and ionospheric incoherent scatter radar returns (so-called MST and ISR signals), short and uncoded pulses will be transmitted to probe the turbulent equatorial electrojet height region (E-region proper) with high temporal and spatial resolution. Short-pulse data from the electrojet will be used to provide gravity wave signatures from the equatorial E region to complement the D-region and upper E-region (above 140 km) gravity wave data acquired in the MST-ISR mode. The overall objective will be to improve the current understanding of gravity wave propagation and guiding in the equatorial mesosphere and lower thermosphere and the role of gravity waves in the structuring of the region via neutral and plasma instability processes. Gravity waves are known to play a crucial role in the dynamic coupling of atmospheric regions. Waves that propagate upward through the mesosphere and lower thermosphere (or that may be generated as secondary waves) may grow to significant amplitudes in the E and F regions of the ionosphere. The fast continuous sampling by the Jicamarca radar provides important information on short period (5-15 minute) gravity wave oscillations and instabilities of the neutral atmosphere at low latitudes. Short period waves are always present in the equatorial mesosphere as evident in Jicamarca vertical wind data and also in the equatorial upper E-region as evident in enhanced backscatter from the 150-km altitude region observed at Jicamarca. The connection of these wave systems and their relation to gravity waves in the intervening E-region altitudes remain unknown and unexplored. Above Jicamarca, this region is occupied by a turbulent equatorial electrojet (EEJ) causing strong radar backscatter. The modulation of this backscatter signal is what will be exploited for a novel study of the gravity wave content of the region and its relationship to gravity waves observed in the mesosphere and the upper E-region.