In this study, one-dimensional spatial distributions of the total liquid water content Q in the extended cloud layers are statistically analyzed. The distributions were derived from the ground measurements of the brightness temperatures of the atmosphere T_B((lambda) ) at wavelengths (lambda) equals 0.8 and 2.3 cm which were carried out during winter monsoon at the northern Taiwan coast. The duration of continuous microwave observations of unbroken clouds ranged from 14 to 225 h. The values of Q were retrieved from the increments of the brightness temperature of the cloud atmosphere relative to the clear one taking into account air temperature and humidity. The 'frozen turbulence' hypothesis was applied to determine spatial distributions of Q. Spatial frequencies of Q variations were found using data on wind speed and direction at the cloud level. The spectral analysis was performed to estimate scale-invariant regimes. The regimes are defined by the scales where spectra follow the power law E(x) approximately exp (-(beta) x). The lower limit of the scales was restricted by an antenna field of view at the cloud level and was about 400 m. The upper limit was a function of the observation duration and the used averaging method and ranged from 40 to 400 km. The results of four case studies are presented. In all cases, the scale-invariant regimes were clearly revealed. Two types of spectra were found: (1) scale-invariant spectra covering the whole scale range analyzed, and (2) spectra with two scale-invariant ranges with (beta) > 2.5 at lower scales and (beta) < 1.5 at upper scales.

Date Published: 28 February 2002
PDF: 8 pages
Proc. SPIE 4678, Eighth International Symposium on Atmospheric and Ocean Optics: Atmospheric Physics, (28 February 2002); doi: 10.1117/12.458512

Published in SPIE Proceedings Vol. 4678:
Eighth International Symposium on Atmospheric and Ocean Optics: Atmospheric Physics
Gelii A. Zherebtsov; Gennadii G. Matvienko; Viktor A. Banakh; Vladimir V. Koshelev, Editor(s)