MSG validation: An Ongoing Process

Paul de Valk(KNMI), Catherine Naud(UCL),

Marcel Derrien, Herve LeGleau(CMS), Tim Smyth (PML), Elizabeth Slack, Charles Wrench (RAL)

 Royal Netherlands Meteorological Institute paul.de.valk@knmi.nl

Contents

Introduction Data: Cloud Top Height SAF-

NWC Results Conclusions

CLOUDMAP2 (funded till January 2004)

Production and exploitation of value-added

remote sensing data products on cloud properties and water vapour distributions to characterise sub-grid scale processes within Numerical Weather Prediction Models (NWP)

through validation and data assimilation.

www.cloudmap.org

Data for validation of Cloud Top Height CTH

SAF-NWC products based on MSG (cloud type, coverage, CTH) 11 and 12 hr

MODIS products produced PML (coverage, CTP)

Chilbolton 94 GHz Radar products (CTH)

Problems encountered Collocation, spatial and temporal Slanted views (polar vs

geostationary) Different pixel size dimensions Different volume sampling Conversion CTP to CTH (HiRLAM)A solution: consider only high coverage

MODIS PML vs SAF-NWC MSG(red line)

Sept 2003 Oct Nov

CTH

Latitudinal dependency, MODIS vs MSG [RED]

< 40 degree 40-45degree > 70 degree

September

Low Medium

High

SemitransparentOver lower

Cloud type dependency of CTH for OctoberMODIS vs MSG [RED]

94 GHz RADAR vs SAF-NWC MSG(red line)

CTH

Sep-Dec2003

RADARVs MSGaverage

BoxesIndicate Max min

Statistics of CTH comparison

Modis vs MSG Bias[m] Std dev [m]

Number

Sept -210 2025 1947574

Oct -200 2261 1523472

Nov -386 2319 2567726

Dec -1080 2649 532402

Radar vs MSG -502 2659 33

Only < 10 km 190 1913 28

Conclusions Good agreement both with MODIS

and Radar, especially high clouds Indication of overestimation of CTH

for low clouds by SAF-NWC but… Latitudinal dependency and Cloud

type dependency of MSG CTH. MODIS PML CTH frequency low at

4000 m