1. © Crown copyright Met Office CCI Cloud Assessment Mark Ringer, Met Office Hadley Centre CMUG 4 th Integration meeting, Exeter – June 2 nd – 4 th, 2014

2. © Crown copyright Met Office Introduction CCI clouds produces a range of cloud parameters: cloud amount, cloud liquid water, cloud effective radius, etc Includes merged (all sensors) and individual sensor products (AATSR, MODIS, AVHRR) Phase 1 prototype data set covers 2007 – 2009 Product definitions correspond to GEWEX cloud assessment – not specifically model-oriented We previously used ISCCP as a precursor data set

3. © Crown copyright Met Office General comments – comparison with other cloud data sets Cloud amount underestimated over global oceans High-level cloud underestimated over land in tropics and mid-latitudes Low-level cloud underestimated over sub-tropical oceanic stratocumulus areas (e.g. California, Peru) Large underestimate of thin cirrus cloud (algorithm? channel selection?)

4. © Crown copyright Met Office Cloud liquid water CCI vs. other data sets: JJA 2007

5. © Crown copyright Met Office Cloud liquid water HadGEM2 vs. obs: JJA 2007

6. © Crown copyright Met Office Cloud droplet effective radius CCI merged product: JJA 2007 OBS MODEL – OBS

7. © Crown copyright Met Office Cloud droplet effective radius CCI individual sensor products OBS MODEL – OBS

8. © Crown copyright Met Office Comments Interpretation of model simulation depends on data set being used for comparison We need to understand how/why CCI differs from other data sets of comparable cloud parameters Why is LWP closer to SSM/I? Why is CCI MODIS/ATSR different from standard MODIS/ATSR products? Interpretation of merged products?

9. © Crown copyright Met Office Phase 2 – modelling perspective A long-term record suitable for identifying trends in cloud would be of great interest…but there are risks Could also focus on interannual variability & model evaluation/development to show value of CCI Consider relation to large amount of current & future work in this area, e.g. CFMIP, WCRP grand challenge on clouds, circulation & climate sensitivity Specific model-oriented products may be required Merged products unlikely to be of use to modellers – emphasis on forward-modelling individual sensors (COSP)

10. © Crown copyright Met Office Interannual variability 1997-98 ENSO: Models vs. ISCCP