The effect of diffusion on tracer puffs simulated by a regional scale Eulerian model
The effect of diffusion on tracer puffs simulated by a regional scale Eulerian model
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区域尺度欧拉模型模拟扩散对示踪烟团的影响
DOI：
10.1029/jd093id03p02389
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发表时间：
1988
影响因子：
--
通讯作者：
Y. Kuo
中科院分区：
文献类型：
--
作者：
R. A. Brost;P. Haagenson;Y. Kuo
在长达1100公里的空间尺度和长达36小时的时间尺度上，我们使用欧拉模型模拟了从地表附近的点源释放的被动示踪剂的传输和扩散。欧拉示踪模式是由6小时探空仪资料的气象分析和欧拉中尺度气象模式的模拟所驱动的。示踪剂模型模拟与在横跨阿巴拉契亚示踪器实验(CAPTEX)期间在86个地面站收集的6小时积分样本进行了比较，以进行6种不同的释放。我们考察了垂直和水平亚格子尺度湍流输送的参数化和有限差分平流格式对示踪剂在地表的浓度和质心轨迹的模拟的影响。结果表明，模拟轨迹误差对垂直涡动扩散系数敏感，对平流方案不敏感，对(水平)数值扩散不敏感。使用70公里的水平分辨率，只有这里测试的最复杂的平流方案(普雷瑟，1986)模拟了在点源释放后的头36小时内水平区域不太大的示踪剂喷发。测试的其他方案(Russell和Lerner，1981；Smolarkiewicz的简化版本，1983)有足够的数值扩散，以至于模拟的水平示踪剂喷发比观测到的喷发要大。示踪剂模型模拟个别释放的能力有相当大的差异，特别是在模拟浓度和观测浓度的定量比较方面。
On a spatial scale of up to 1,100 km and a temporal scale of up to 36 hours, we used Eulerian models to simulate the transport and diffusion of a passive tracer released from a point source near the surface. An Eulerian tracer model was driven by meteorological analysis of 6-hour rawinsonde data supplemented by the simulations of an Eulerian mesoscale meteorological model. The tracer model simulations were compared with 6-hour integrated samples collected at 86 surface stations during the Cross-Appalachian Tracer Experiment (CAPTEX) for six different releases. We examined the effect of the parameterizations of vertical and horizontal sub-grid scale turbulent transport and the finite difference advection scheme on the simulations of concentration and the trajectories of the center of mass of the tracer at the surface. We found that the simulated trajectory error was sensitive to the vertical eddy diffusivity but insensitive to the advection scheme and hence insensitive to (horizontal) numerical diffusion. Using 70-km horizontal resolution, only the most sophisticated advection scheme tested here (Prather, 1986) simulated a tracer puff with a horizontal area that was not too large during the first 36 hours after a point source release. The other schemes tested (Russell and Lerner, 1981; a simplified version of Smolarkiewicz, 1983) had enough numerical diffusion that the simulated horizontal tracer puffs were larger than the observed puffs. There were considerable differences in the capability of the tracer models to simulate individual releases, particularly for quantitative comparisons of simulated and observed concentrations.