Open AccessTime correlations and 1/ f behavior in backscattering radar reflectivity measurements from cirrus cloud ice fluctuations
Author(s) -
Ivanova K.,
Ackerman T. P.,
Clothiaux E. E.,
Ivanov P. Ch.,
Stanley H. E.,
Ausloos M.
Publication year - 2003
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2002jd003000
Subject(s) - cirrus , ice crystals , depth sounding , ice cloud , cloud physics , radar , doppler effect , atmospheric sciences , physics , power law , atmosphere (unit) , computational physics , geology , environmental science , radiative transfer , cloud computing , meteorology , optics , telecommunications , oceanography , statistics , mathematics , astronomy , computer science , operating system
The state of the atmosphere is governed by the classical laws of fluid motion and exhibits correlations in various spatial and temporal scales. These correlations are crucial to understand the short‐ and long‐term trends in climate. Cirrus clouds are important ingredients of the atmospheric boundary layer. To improve future parameterization of cirrus clouds in climate models, it is important to understand the cloud properties and how they change within the cloud. We study correlations in the fluctuations of radar signals obtained at isodepths of winter and fall cirrus clouds. In particular, we focus on three quantities: (1) the backscattering cross‐section, (2) the Doppler velocity, and (3) the Doppler spectral width. They correspond to the physical coefficients used in Navier Stokes equations to describe flows, i.e., bulk modulus, viscosity, and thermal conductivity. In all cases we find that power law time correlations exist with a crossover between regimes at about 3 to 5 min. We also find that different type of correlations, including 1/ f behavior, characterize the top and the bottom layers and the bulk of the clouds. The underlying mechanisms for such correlations are suggested to originate in ice nucleation and crystal growth processes.