Monday, 15 July 2002
Statistical analysis of the clouds diurnal evolution in the PBL
The statistical analysis is focused on the investigation of the self-affine and multi-affine properties (and their diurnal variation) of cloud base height data records. The data, used in the paper are measured during two programs: the Atlantic Stratocumulus Transition Experiment (ASTEX) held in June 1992, at the Azores Islands for marine BL and the Atmospheric Radiation Measurement Program of the Department of Energy - the Southern Great Plains (SGP) (Oklahoma, USA) for continental BL. The scaling ranges of time correlations in the cloud base height records of boundary layer startus/stratocumulus clouds are studied, applying the Detrended Fluctuation Analysis statistical method [1]. We found that time dependent variations in the evolution of the similarity parameter (a)reflect the diurnal dynamics of cloud base height fluctuations in the both types of boundary layer - marine and continental. The generalized dimensions [2,3], determining the intermittency of the signals are studied. The multi-affine properties, described by h(g) functions [4,5,6] are determined also. The results are oriented toward the understanding, modeling and predicting the dynamical behavior of the cloud base evolution, governed by the boundary layer dynamics.
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