On the temporal evolution of turbopause altitude
On the temporal evolution of turbopause altitude
复制标题
涡轮顶高度的时间演化
DOI：
10.1017/exp.2021.6
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发表时间：
2021
影响因子：
--
通讯作者：
and S. Nozawa
中科院分区：
文献类型：
--
作者：
Hall;C.M.;and S. Nozawa
具有多个接收器的中频雷达能够根据折射率不规则性的回波跟踪地面上干涉图案的移动。特别是，中间层的折射率由电子密度决定-通常称为电离层D区。因此，使用这种技术，有可能确定70-90公里高度范围内的风，这取决于全年的电离度。此外，通过检查这些结构的通道的衰落时间，可以推断出与中性空气湍流有关的度量。在这里，我们采用了一种行之有效的方法来达到这一效果。然后，将湍流强度与中性大气的运动粘滞系数进行比较，确定湍流顶高度。在这一高度之上，大气成分的行为是独立的，而在这一高度之下，所有成分都是混合的。与先前的分析相反，我们提出的证据表明，自2004年以来，湍流层顶高度一直是恒定的。
Medium frequency radars with multiple receivers are able to track the movement of the interference pattern on the ground from echoes from irregularities in refractive index. In particular, refractive index in the mesosphere is determined by electron density – commonly known as the ionospheric D-region. Thus using this technique it is possible to determine winds in the height regime 70-90 km, depending on the degree of ionization throughout the year. In addition, by examining the fading times of the passage of these structures, it is possible to deduce metrics pertaining to neutral air turbulence. Here, we employ a well-established method to this effect. Thereafter, comparing the turbulent intensity to the kinematic viscosity of the neutral atmosphere, we determine the turbopause altitude. Above this height, atmospheric constituents behave independently, whereas below, all components are mixed. Contrary to earlier analyses, we present evidence the turbopause altitude has been constant since approximately 2004.