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

该奖项将确定山波的破裂如何影响地球表面上大约100-200英里的空间天气。山浪是由风吹过山脉而产生的。当山波达到山的高度时，山波就会破碎并翻转，类似于海浪在海滩上的破碎。这个过程会产生湍流和大范围的波，这些波会传播到地球上空更高的地方。在距离地球表面100-200英里的地方，波中的中性分子与离子碰撞，在等离子体中产生被称为电离层扰动（TIDs）的波。其中一些tid在GPS接收器的总电子含量地图上看起来像圆环。TIDs会在太空天气中引发风暴，使地球与环绕地球运行的卫星通信变得困难。了解能量和动量如何通过几个重力波产生和耗散循环（包括二次和三次重力波过程（多步垂直耦合过程））在大气区域传递是很重要的。该项目包括2名本科生，为期3年。因此，这项研究将进一步发展和教育具有全球竞争力的STEM劳动力，并将促进科学的进步。该队将分享GPS/TEC信号处理程序，这将使社区受益。本研究的主要目的是通过详细的观测研究，确定1)冬季美国大陆（CONUS）和欧洲大陆（CONUS）和欧洲大陆（CONUS）上空的重力波（GW）特征和同心传播电离层扰动的来源；2)通过详细的模式研究，确定冬季美国大陆和欧洲大陆的地形强迫在热层产生高阶GWs的“多步垂直耦合”（MSVC）过程。由于GPS/TEC在南美洲和欧洲的观测密集，这些位置为研究这些同心tid提供了理想的位置。该团队将识别和分析GPS/TEC在2012-2023年5个冬季的12月至2月的安静期观测到的同心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。他们将讨论问题1:GPS在冬季南美洲和欧洲观测到的安静时间同心tid的GW特征、位置、发生率和来源是什么？和SQ2：通过何种模拟耦合过程，在CONUS和欧洲上空的地形强迫在热层中产生高阶同心GWs ?导致热层的大尺度变化是什么？方法包括HIAMCM、射线追踪模型（重力波源、射线追踪和重建模型（MESORAC））、公开的NRLMSISE-00和HWM14模型、MERRA-2再分析数据、GOES和EUMETSAT卫星数据以及GPS/TEC数据。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.