Relative Diffusion of Constant-Level Balloons in the Southern Hemisphere
Relative Diffusion of Constant-Level Balloons in the Southern Hemisphere
复制标题
南半球恒定高度气球的相对扩散
DOI：
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发表时间：
1981
期刊：
影响因子：
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通讯作者：
R. Peskin
中科院分区：
文献类型：
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作者：
J. Er;R. Peskin
本文分析了TWERLE气球示踪剂在南半球150毫巴水平和50-10,000公里尺度上的相对弥散。引入了两粒子时间尺度，定义为相对速度相关的时间积分。该时间尺度是气球对之间的初始相对距离和拉格朗日积分长度尺度的函数。对相对位移数据的分析表明，在气球释放后的短时间内存在指数增长区域，而在较大时间内(但小于两粒子时间尺度)存在T3区域。指数区可以被认为是拟能级联范围内相对色散的表现，而T3区表示后向能量传输区中的相对色散。典型的相对位移概率分布函数表现出较大的峰度。这可以看作是对存在局部/非局部混合应变机制的确认。
Abstract The TWERLE balloon tracers are analyzed for relative dispersion in the 150 mb level of the Southern Hemisphere and scales of 50–10 000 km. A two-particle time scale is introduced and is defined as the time integral of the relative-velocity correlation. This time scale is a function of both the initial relative distance between the pair of balloons and the Lagrangian integral length scale. Analysis of the relative-displacement data reveals an exponential growth region for short times after the release of the balloons and a t3 region for larger times (but smaller than the two-particle time scale). The exponential region can be considered as a manifestation of relative dispersion in an enstrophy cascade range while a t3 region indicates relative dispersion in a backward energy transfer region. Typical probability distribution functions of the relative displacement exhibit large kurtosis values. This can be regarded as a confirmation on the existence of a mixed local/nonlocal straining mechanism whic...