The contribution of this author was written in the course of his employment at the Met Office, UK, and is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.
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Research Article
Evaluation of ice cloud representation in the ECMWF and UK Met Office models using CloudSat and CALIPSO data
Article first published online: 5 AUG 2011
DOI: 10.1002/qj.882
Copyright © 2011 Royal Meteorological Society and British Crown Copyright, the Met Office
Issue
Quarterly Journal of the Royal Meteorological Society
Special Issue: The use of cloud and precipitation observations in data assimilation (CPDA)
Volume 137, Issue 661, pages 2064–2078, October 2011 Part B
Additional Information
How to Cite
Delanoë, J., Hogan, R. J., Forbes, R. M., Bodas-Salcedo, A. and Stein, T. H. M. (2011), Evaluation of ice cloud representation in the ECMWF and UK Met Office models using CloudSat and CALIPSO data. Q.J.R. Meteorol. Soc., 137: 2064–2078. doi: 10.1002/qj.882
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The contribution of this author was written in the course of his employment at the Met Office, UK, and is published with the permission of the Controller of HMSO and the Queen's Printer for Scotland.
Publication History
- Issue published online: 7 DEC 2011
- Article first published online: 5 AUG 2011
- Manuscript Accepted: 7 JUN 2011
- Manuscript Revised: 6 JUN 2011
- Manuscript Received: 8 SEP 2010
- Abstract
- Article
- References
- Cited By
Keywords:
- model comparison;
- A-Train;
- ice cloud properties
Abstract
Ice cloud representation in general circulation models remains a challenging task, due to the lack of accurate observations and the complexity of microphysical processes. In this article, we evaluate the ice water content (IWC) and ice cloud fraction statistical distributions from the numerical weather prediction models of the European Centre for Medium-Range Weather Forecasts (ECMWF) and the UK Met Office, exploiting the synergy between the CloudSat radar and CALIPSO lidar. Using the last three weeks of July 2006, we analyse the global ice cloud occurrence as a function of temperature and latitude and show that the models capture the main geographical and temperature-dependent distributions, but overestimate the ice cloud occurrence in the Tropics in the temperature range from −60 °C to −20 °C and in the Antarctic for temperatures higher than −20 °C, but underestimate ice cloud occurrence at very low temperatures. A global statistical comparison of the occurrence of grid-box mean IWC at different temperatures shows that both the mean and range of IWC increases with increasing temperature. Globally, the models capture most of the IWC variability in the temperature range between −60 °C and −5 °C, and also reproduce the observed latitudinal dependencies in the IWC distribution due to different meteorological regimes. Two versions of the ECMWF model are assessed. The recent operational version with a diagnostic representation of precipitating snow and mixed-phase ice cloud fails to represent the IWC distribution in the −20 °C to 0 °C range, but a new version with prognostic variables for liquid water, ice and snow is much closer to the observed distribution. The comparison of models and observations provides a much-needed analysis of the vertical distribution of IWC across the globe, highlighting the ability of the models to reproduce much of the observed variability as well as the deficiencies where further improvements are required. Copyright © 2011 Royal Meteorological Society and British Crown Copyright, the Met Office