The Advection of High-Resolution Tracers by Low-Resolution Winds
The Advection of High-Resolution Tracers by Low-Resolution Winds
复制标题
低分辨率风对高分辨率示踪剂的平流作用
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
B. Hoskins
中科院分区：
文献类型：
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作者：
J. Methven;B. Hoskins
摘要利用低分辨率风模拟大气示踪剂是否有用，既取决于大空间尺度在应变中的优势，也取决于导致示踪剂尺度上的级联的时间相关性。本文利用等高线平流技术对这类示踪研究的精度进行了定量研究。结果表明，虽然等值线伸缩率对风场的空间截断非常不敏感，但灯丝位置的位移误差是敏感的。如果要将拉格朗日模拟用于气团起源的推断，位移特征的知识是必不可少的。得到了示踪尺度因子(TSF)的一个定量下限估计：平流风场中的最小可分辨尺度与示踪场中最小的“可信”尺度之比。对于斜压波生命周期，TSF=6.1±0.3，而对于北半球冬季平流层低层，TSF=5.5±0.5，当使用最严格的
Abstract The usefulness of any simulation of atmospheric tracers using low-resolution winds relies on both the dominance of large spatial scales in the strain and time dependence that results in a cascade in tracer scales. Here, a quantitative study on the accuracy of such tracer studies is made using the contour advection technique. It is shown that, although contour stretching rates are very insensitive to the spatial truncation of the wind field, the displacement errors in filament position are sensitive. A knowledge of displacement characteristics is essential if Lagrangian simulations are to be used for the inference of airmass origin. A quantitative lower estimate is obtained for the tracer scale factor (TSF): the ratio of the smallest resolved scale in the advecting wind field to the smallest “trustworthy” scale in the tracer field. For a baroclinic wave life cycle the TSF = 6.1 ± 0.3 while for the Northern Hemisphere wintertime lower stratosphere the TSF = 5.5 ± 0.5, when using the most stringent ...