Lagrangian Studies of Stratospheric Transport Barriers

[9714384] Eluszkiewicz首席研究员试图了解平流层中痕量物种穿越内部屏障（如对流层顶和热带和温带之间的边界）运输的物理过程。跨越这些边界的运输速率对于确定关键组成气体（包括平流层水蒸气和平流层下层和对流层臭氧）的预算具有重要意义，并且在评估微量气体（例如超音速和亚音速飞机）排放到大气中的化学和气候影响方面发挥关键作用。尽管认识到它的重要性，但相关的空间尺度往往小于航天器观测或欧拉平流方案所能解决的问题，这一事实阻碍了理解这种传输的进展。在这个项目下，PI将使用一个特别开发的拉格朗日轨迹包，并将其纳入地球物理流体动力学实验室SKYHI环流模型（GCM），模拟大尺度和小尺度运输的全球影响。拉格朗日技术将用于探讨以下问题：（使用欧拉和拉格朗日方法计算的微量气体分布的差异，以及这些差异对GCM计算的平流层空气平均年龄的影响）(模式模拟的对流层顶质量通量所揭示的温带平流层-对流层交换的性质和季节模式。从这项研究中获得的见解将有助于其他gcm和/或同化模型的轨迹技术的一般发展。特别是，本研究将研究在轨迹计算中使用的风数据对垂直坐标选择和采样频率的敏感性，包括在线计算的选择，即在风力发电模型的每个积分时间步长上进行计算。因此，这些研究将有助于更好地理解拉格朗日方法作为三维高分辨率平流方案和可视化工具。

9714384 Eluszkiewicz The principal investigator seeks to understand the physical processes responsible for transport of trace species in the stratosphere across internal barriers such as the tropopause and the boundary between the tropics and extratropics. The transport rates across these boundaries are important in determining the budgets of key constituent gases, including stratospheric water vapor and lower stratospheric and tropospheric ozone, and play a crucial role in the assessment of the chemical and climatic impact of trace gases emitted to the atmosphere, for example by supersonic and subsonic aircraft. Despite its recognized importance, progress in understanding this transport has been impeded by the fact that the relevant spatial scales are often smaller than can be resolved by spacecraft observations or computed using Eulerian advection schemes. Under this project the PI will simulate the global effects of both large and small scale transport using a specially developed Lagrangian trajectory package incorporated into the Geophysical Fluid Dynamics Laboratory SKYHI general circulation model (GCM). The Lagrangian technique will be used to explore the following: ( The difference in the trace gas distributions computed using Eulerian and Lagrangian approaches and the impact of these differences on the mean age of stratospheric air as computed in a GCM ( The nature of stratosphere-troposphere exchange in the extratropics and the seasonal patterns as revealed by the mass fluxes across the tropopause simulated in the model. Insights gained from this research will be useful in the general development of trajectory techniques for other GCMs and/or assimilation models. In particular, this research will study the sensitivity to the choice of vertical coordinate and to the sampling frequency of the wind data used in the trajectory calculations, including the option of performing the calculations on-line, i.e., on each integration time step of the wind-generating model. These studies will thus contribute to a better understanding of the Lagrangian approach both as a three-dimensional high-resolution advection scheme and as a visualization tool.