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Published byValentin Gerhardt Modified over 6 years ago
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Using satellite simulators for cloud evaluation
Keith Williams WGNE31, 27/04/16 © Crown copyright Met Office
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CloudSat CALIPSO ISCCP MODIS MISR (RTTOV)
CFMIP web: cfmip.metoffice.com/COSP.html User group: groups.google.com/group/cosp-user © Crown copyright Met Office (Bodas-Salcedo et al., BAMS, DOI: /2011BAMS )
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Bias in cloud cover (against CALIPSO – cloud lidar)
© Crown copyright Met Office
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Tropics © Crown copyright Met Office
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Comparison against satellite data over the tropics
ISCCP CALIPSO CloudSat Excess hydro-meteor at low levels Too little medium brightness cloud Excessive cirrus and too low © Crown copyright Met Office Excess “drizzle” (<0.005mm/hr)
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Comparison against satellite data over the tropics
ISCCP CALIPSO CloudSat Reduced cirrus spreading rate © Crown copyright Met Office 6A convection Warm rain microphys
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Case study VT: 18Z 17/12/2010 (T+6) © Crown copyright Met Office
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CALIPSO composites (mean over tropics)
By SST: Cool Warm By vertical velocity: Strong subsidence Strong ascent
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Mid-latitude storm tracks
© Crown copyright Met Office
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Case study VT: 15Z 16/02/2011 (T+27) © Crown copyright Met Office
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Composite cyclone: RL-GEOPROF hydrometeor frac.
Northern hemisphere winter Following Govekar et al. (2014) (cyclone compositing using Field and Wood, 2007)
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Composite cyclone: GA6 hydrometeor frac bias
Northern hemisphere winter © Crown copyright Met Office
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Composite cyclone: GA7 hydrometeor frac bias
Northern hemisphere winter © Crown copyright Met Office
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Composite cyclone: GA6 cloud albedo bias
Winter Summer Northern hemisphere: Southern hemisphere: © Crown copyright Met Office
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Discussion At the Met Office, we have found satellite simulators extremely valuable for model development. The climate community conduct routine comparisons of satellite simulator output as part of CFMIP. The diagnostics are requested as standard in CMIP. Is COSP typically being used within NWP centres? Would it be useful for a similar inter-comparison to be undertaken amongst NWP models? Comparison against current instruments is best before Is it too difficult to re-run forecasts for this period (no need to re-run DA)? Is it best to start now (and get improving models) or wait for EarthCARE (~2018)? © Crown copyright Met Office
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© Crown copyright Met Office
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