Analysis and improvements of cloud models for propagation studies
Article first published online: 20 MAR 2009
Copyright 2009 by the American Geophysical Union.
Volume 44, Issue 2, April 2009
How to Cite
2009), Analysis and improvements of cloud models for propagation studies, Radio Sci., 44, RS2005, doi:10.1029/2008RS003876., , , , and (
- Issue published online: 20 MAR 2009
- Article first published online: 20 MAR 2009
- Manuscript Accepted: 12 JAN 2009
- Manuscript Revised: 6 NOV 2008
- Manuscript Received: 16 APR 2008
 Two cloud models currently in use in propagation and remote sensing simulations in the presence of nonprecipitating clouds were analyzed. A new cloud model is also proposed: a modification of a humidity threshold to better identify clouds is suggested, as is a new cloud density function for computing cloud liquid and ice content within a cloud. The performances of the threshold functions were examined at the Atmospheric Radiation Measurement (ARM) Program's Southern Great Plaints (SGP) site in Oklahoma, USA, by using radiosonde and ceilometer data. The new threshold showed an improvement in the cloud detection (15%) and a reduction of false cloud identification in clear-sky conditions (26%). Next, the cloud density models were evaluated in the brightness temperature (Tb) domain, by comparing simulated Tb values in cloudy conditions with those measured by dual-channel microwave radiometers at several ARM sites. The new model provided good results in comparison with the radiometer measurements, with overall root mean square (RMS) differences of 3.10 K, reducing the RMS by about 16% with respect to the best of the other models. Improvements can be noticed in particular at SGP (20%), and in the tropics (37%).