Collaborative Research: CEDAR--Higher-Order Concentric Gravity Waves in the Northern Winter Thermosphere and Ionosphere

这一奖项将确定山波的破裂如何影响地球表面约100-200英里处的空间天气。山浪是由风在山上流动而产生的。当山上的海浪升得足够高时，它们就会破裂和倾覆，就像海浪在海滩上破碎一样。这一过程产生了湍流和大尺度波，它们传播到地球上空更高的高度。在地球表面以上100-200英里处，波中的中性分子与离子碰撞，在等离子体中产生波，称为行进电离层扰动(TID)。在GPS接收器的总电子含量地图上，其中一些TID看起来像圆形环。TID会在太空天气中造成风暴，使其难以与围绕地球运行的卫星进行通信。了解能量和动量是如何通过几个重力波产生和消散循环，包括二次和三次重力波过程(多步骤垂直耦合过程)通过大气区转移的，这一点很重要。本项目包括2名本科生，为期3年，为期3年。因此，这项研究将进一步发展和教育一支具有全球竞争力的STEM劳动力队伍，并将促进科学进步。该团队将分享GPS/TEC信号处理例程，这将使社区受益。这项研究的主要目的是通过详细的观测研究来确定1)安静的冬季美国大陆(CONUS)和欧洲上空同心行进电离层扰动的重力波(GW)特征和来源，以及2)通过详细的模拟研究确定通过冬季CONUS和欧洲的地形强迫在热层中产生高阶GW的“多步垂直耦合”(MSVC)过程。由于GPS/TEC观测在CONUS和欧洲上空密集，这些地点为研究这些同心TID提供了理想的位置。该小组将识别和分析2012-2023年5个冬季由GPS/TEC在12-2月期间观测到的同心TID事件，并将使用GW分辨率高海拔机械环流模式(HIAMCM)模拟和分析6-9个一周的山波(MW)事件。他们将讨论SQ1：全球定位系统在冬季、CONUS和欧洲观测到的静止同心TID的GW特征、位置、发生率和来源是什么？和SQ2：CONUS和欧洲的地形强迫通过什么模拟的耦合过程在热层中产生更高阶的同心GW，以及导致热层的大尺度变化是什么？该方法包括HIAMCM、射线跟踪模型(重力波源、射线跟踪和重建模型(MESORAC))，以及公开可用的NRLMSISE-00和HWM14模型、MERRA-2再分析数据、GO和EUMETSAT卫星数据以及GPS/TEC数据。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award will determine how the breaking of mountain waves affects space weather approximately 100-200 miles above the Earth’s surface. Mountain waves are created from the wind flowing over mountains. Mountain waves break and overturn when they get high enough above the mountains, similar to an ocean wave breaking on a beach. This process generates turbulence and large-scale waves which travel to higher heights above Earth. At 100-200 miles above the Earth’s surface, the neutral molecules in the waves collide with ions, which creates waves in the plasma called traveling ionospheric disturbances (TIDs). Some of these TIDs look like circular rings on maps of the total electron content from GPS receivers. TIDs can cause storms in the space weather that make it difficult to communicate with the satellites that orbit Earth. Understanding how energy and momentum are transferred through atmospheric regions via several gravity wave generation and dissipation cycles including secondary and tertiary gravity wave processes (multi-step vertical coupling processes) is important. This project includes 2 undergraduate students during the summertime for the 3-year duration of this grant. This research will therefore further the development and education of a globally competitive STEM workforce and will promote the progress of science. The team will share GPS/TEC signal processing routines which will benefit the community. The main objectives of this research are to determine 1) the gravity wave (GW) characteristics and sources of concentric traveling ionospheric disturbances over the quiettime winter continental United States (CONUS) and Europe through detailed observational studies, and 2) the “multi-step vertical coupling” (MSVC) processes which create higher-order GWs in the thermosphere from orographic forcing over the winter CONUS and Europe through detailed modeling studies. Because GPS/TEC observations are dense over the CONUS and Europe, these locations provide ideal locations to study these concentric TIDs. The team will identify and analyze concentric TID events observed by GPS/TEC during quiettime December-February for 5 winters during 2012-2023, and will simulate and analyze 6-9 one-week mountain wave (MW) events with the GW-resolving HIgh Altitude Mechanistic general Circulation Model (HIAMCM). They will address SQ1: What are the GW characteristics, locations, occurrence rates, and sources of the quiettime concentric TIDs observed by GPS over the winter CONUS and Europe? and SQ2: What are the simulated coupling processes by which orographic forcing over the CONUS and Europe creates higher-order concentric GWs in the thermosphere, and what are the large-scale changes that result in the thermosphere? The methodology includes HIAMCM, a ray trace model (the Model for gravity wavE SOurce, Ray trAcing and reConstruction (MESORAC)), and publicly-available NRLMSISE-00 and HWM14 models, MERRA-2 reanalysis data, GOES and EUMETSAT satellite data and GPS/TEC data.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.