Comparison of cloud products within IASI footprints for the assimilation of cloudy radiances

Authors

L. Lavanant, Météo-FranceFollow
N. Fourrié, Météo-France
A. Gambacorta, NOAA/NESDIS/PSGS
G. Grieco, Universita della Basilicata
S. Heilliette, Environment Canada
F. I. Hilton, Met Office
M. -J Kim, Colorado State University - Fort Collins
A. P. McNally, ECMWF
H. Nishihata, Japan Meteorological Agency
E. G. Pavelin, Met Office
F. Rabier, Météo-France

Date of this Version

2011

Comments

Published in Q. J. R. Meteorol. Soc. (2011) 16 p.; DOI:10.1002/qj.917

Abstract

This article compares different methods of deriving cloud properties in the footprint of the Infrared Atmospheric Sounding Interferometer (IASI), onboard the European MetOp satellite. Cloud properties produced by ten operational schemes are assessed and an intercomparison of the products for a 12 h global acquisition is presented. Clouds cover a large part of the Earth, contaminating most of the radiance data. The estimation of cloud top height and effective amount within the sounder footprint is an important step towards the direct assimilation of cloud-affected radiances. This study first examines the capability of all the schemes to detect and characterize the clouds for all complex situations and provides some indications of confidence in the data. Then the dataset is restricted to thick overcast single layers and the comparison shows a significant agreement between all the schemes. The impact of the retrieved cloud properties on the residuals between calculated cloudy radiances and observations is estimated in the long-wave part of the spectrum.