elib
DLR-Header
DLR-Logo -> http://www.dlr.de
DLR Portal Home | Imprint | Contact | Deutsch
Fontsize: [-] Text [+]

Surrogate cloud fields generated with the Iterative Amplitude Adapted Fourier Transform algorithm

Venema, Victor and Meyer, Steffen and Gimeno-Garcia, Sebastian and Kniffka, Anke and Simmer, Clemens and Crewell, Susanne and Löhnert, Ulrich and Trautmann, Thomas and Macke, Andreas (2006) Surrogate cloud fields generated with the Iterative Amplitude Adapted Fourier Transform algorithm. Tellus A - Dynamic Meteorology and Oceanography, 58A, pp. 104-120. Tellus. DOI: 10.1111/j.1600-0870.2006.00160.x.

Full text not available from this repository.

Abstract

A new method of generating two-dimensional and three-dimensional cloud fields is presented, which share several important statistical properties with real measured cloud fields. Well-known algorithms such as the Fourier method and the Bounded Cascade method generate fields with a specified Fourier spectrum. The new iterative method allows for the specification of both the power spectrum and the amplitude distribution of the parameter of interest, e.g. the liquid water content or liquid water path. As such, the method is well suited to generate cloud fields based on measured data, and it is able to generate broken cloud fields. Important applications of such cloud fields are e.g. closure studies. The algorithm can be supplied with additional spatial constraints which can reduce the number of measured cases needed for such studies. In this study the suitability of the algorithm for radiative questions is evaluated by comparing the radiative properties of cloud fields from cloud resolving models of cumulus and stratocumulus with their surrogate fields at nadir, and for a solar zenith angle of 0° and 60°. The cumulus surrogate clouds ended up to be identical to the large eddy simulation (LES) clouds on which they are based, except for translations and reflections. The root mean square differences of the stratocumulus transmittance and reflectance fields are less than 0.03% of the radiative budget. The radiances and mean actinic fluxes fit better than 2%. These results demonstrate that these LES clouds are well described from a radiative point of view, using only a power spectrum together with an amplitude distribution.

Document Type:Article
Title:Surrogate cloud fields generated with the Iterative Amplitude Adapted Fourier Transform algorithm
Authors:
AuthorsInstitution or Email of Authors
Venema, VictorMeteorological Institute of Bonn University
Meyer, SteffenLeibniz-Institut für Meereswissenschaften Kiel
Gimeno-Garcia, SebastianUniversity of Leipzig
Kniffka, AnkeUniversity of Leipzig
Simmer, ClemensMeteorological Institute of Bonn University
Crewell, SusanneMeteorological Institute of Bonn University
Löhnert, UlrichMeteorological Institute of Bonn University
Trautmann, ThomasUNSPECIFIED
Macke, AndreasLeibniz-Institut für Meereswissenschaften Kiel
Date:2006
Journal or Publication Title:Tellus A - Dynamic Meteorology and Oceanography
Refereed publication:Yes
In ISI Web of Science:Yes
Volume:58A
DOI:10.1111/j.1600-0870.2006.00160.x
Page Range:pp. 104-120
Publisher:Tellus
Status:Published
Keywords:Radiative transfer, Statistical cloud generator, Radiative properties of clouds
HGF - Research field:Aeronautics, Space and Transport (old)
HGF - Program:Space (old)
HGF - Program Themes:W EO - Erdbeobachtung
DLR - Research area:Space
DLR - Program:W EO - Erdbeobachtung
DLR - Research theme (Project):W - Vorhaben Entwicklung von Atmosphärenprozessoren (old)
Location: Oberpfaffenhofen
Institutes and Institutions:Remote Sensing Technology Institute > Atmospheric Processors
Deposited By: Brigitte Rüba
Deposited On:23 Mar 2006
Last Modified:07 Apr 2010 10:07

Repository Staff Only: item control page

Browse
Search
Help & Contact
Informationen
electronic library is running on EPrints 3.3.12
Copyright © 2008-2012 German Aerospace Center (DLR). All rights reserved.