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The Satellite Global Observing System Stephen English A brief introduction to the Satellite GOS Monitoring of satellite observations OSCAR – WMO’s database for global observations, user requirements and gap-analysis. What types of satellites are used in NWP?. Advantages Disadvantages
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The Satellite Global Observing System • Stephen English • A brief introduction to the Satellite GOS • Monitoring of satellite observations • OSCAR – WMO’s database for global observations, user requirements and gap-analysis
What types of satellites are used in NWP? Advantages Disadvantages GEO - Regional coverage No global coverage by single satellite - Temporal coverage LEO- Global coverage with single satellite
Composition Ultraviolet sensors Sub-mm, and near IR plus Visible (e.g. Lidar) Polar IR + MW sounders Mass Radar and GPS total path delay Moisture Radio occultation Geo IR Sounder Geo IR and Polar MW Imagers Feature tracking in imagery (e.g. cloud track winds), scatterometers and doppler winds IR = InfraRed MW = MicroWave Wind
Combined impact of all satellite data • EUCOS Observing System Experiments (OSEs): • 2007 ECMWF forecasting system, • winter & summer season, • different baseline systems: • no satellite data (NOSAT), • NOSAT + AMVs, • NOSAT + 1 AMSU-A, • general impact of satellites, • impact of individual systems, • all conventional observations. • 500 hPa geopotential height anomaly correlation 3/4 day 3 days
Email-alert Email alert: Soft limits (mean ± 5 stdev being checked, calculated from past statistics over a period of 20 days, ending 2 days earlier) Hard limits (fixed) Data monitoring – automated warnings http://www.ecmwf.int/products/forecasts/satellite_check/ Selected statistics are checked against an expected range. E.g., global mean bias correction for GOES-12 (in blue): (M. Dahoui & N. Bormann)
Satellite data monitoring Data monitoring – automated warnings
Global Observing System is essential to weather forecasting Technology driven….a more integrated approach now? Mass is well observed. Moisture – satellite observations are data rich but poorly exploited. Radar and lidar will become more important. Dynamics – even wind observations are scarce. Composition – NWP techniques have been successfully extended to environmental analysis and prediction but more observations are needed. Surface – DA for surface fields is being attempted.
User requirements http://www.wmo-sat.info/db/ • Vision for the GOS in 2025 adopted June 2009 • GOS user guide WMO-No. 488 (2007) • Manual of the GOS WMO-No. 544 (2003) (Update of satellite section being prepared for ET-SAT Geneva April 2012)
Sun-Synchronous Polar Satellites (2) Non Sun-Synchronous Observations