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Satellite Evaluation work at Reading
Julien Delanoë/Thorwald Stein/Robin Hogan
Collaborations: Richard Forbes (ECMWF)/
Alejandro Bodas-Salcedo (MetOffice)
Cloud/radar/radiation collaboration meetingHow best can we work together to evaluate model changes
17-18 November in Reading
What do we do from space?Evaluation of cloud representation in models
We retrieve cloud fraction and cloud properties• Ice clouds/precip (Julien/Thorwald/Robin)Ice cloud fraction/frequency of occurrence/IWC/IWP
• Mixed phase clouds (Julien/Robin)Supercooled water fraction
UM+Simulator vs CloudSat (Thorwald)40km
Same Z threshold
OLD: old PSD parameterisationNEW: new PSD parameterisation, consistent with UM
Model, narrower distribution.
Why does the new model show a shifted distribution to the small Z?The inconsistent param does not look closer to CloudSat
40km
Obs
Lat
Temperature
12km
40km
Indo-Pacific 9-16 Oct 08V
ertic
al d
istr
ibut
ion
Horizontal distribution
New PSD
Frequency of Occurrence of iceMore ice clouds in models!
UMIWC narrower distributionHigher IWCHigher IWP
ECMWFSimilar dist but lack of low T cloudsBetter agreement than UM for IWP
Mixed phase cloudsJanuary to December 2007
Z-Z
top
()km
Conclusion
• Data availability:– Cloud mask, entire period of CloudSat/CALIPSO– Ice properties: 1,5 years (all 2007)
• What would modellers need to improve Cloud representation in GCM?
For discussion
All
NorthPole
NorthernMidlats
SouthernMidlats
Tropicalbelt
SouthPole
Supercooled layer