Characterisation of tropospheric turbulent layers from radiosonde data

Comparison of the refractive index structure constant prediction using radiosonde data to in-situ thermosonde measurements

“…We also compute the average of the refractive index constant for bin size of 50m, 100m and 300m, in order to determine how well the observations and model estimates are in agreement. Notice such averages are used to estimate optical "seeing" and scintillation variance [1][2][3][4][5][6][7][8], and [10][11][12][13][14]. We often found discrepancies, between measured and computed refractive index constant of up to 2 orders of magnitude, by using both models.…”

“…Atmospheric turbulence can significantly affect the received field amplitude by degrading the signal-to-noise ratio. On the other hand, measurement of the refractive-index fluctuation intensity can provide information on the local state of the atmosphere itself, which is of great interests to atmospheric physics research [1][2][3][4][5][6][12][13][14][15][16]. Atmospheric scintillation is caused by small-scale fluctuations of the refractive index due to the turbulence.…”

“…Scintillation yields random fades and enhancements of the received signal, which could impair the availability of low-margin systems particularly at low-elevation angles, interfering with tracking systems and fade mitigation techniques. Scintillation has to be considered in the design and planning of satellite communications systems at frequencies above 10 GHz [13][14][15].…”

The Development of Volcanic Ash Cloud Layers over Hours to Days Due to Atmospheric Turbulence Layering

“…The free atmosphere itself, with or without volcanic clouds, generates small-scale turbulent eddies. Eddies are generally created in the troposphere by Rayleigh-Taylor (convective) instabilities associated with clouds, and can be found 33% of the time [29]. In the stratosphere, clear-air turbulence (CAT) is primarily thought to be generated by breaking of upward-propagated gravity waves from the troposphere or tropopause, i.e., the Kelvin-Helmholtz mechanism, acting during episodes of vertical wind shear in the horizontal wind components [30][31][32].…”

“…Kelvin-Helmholtz instability is driven by the shear between the intruding cloud and the atmosphere [33]. Rayleigh-Taylor instability is driven by cloud top convective instabilities [29], convective sedimentation, fingering and local, eddy scale density reversal [11,16,34].…”