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Introduction to the COMS Meteorological Data Processing System Myoung-Hwan Ahn/RSRL 2005. 06. 02

Introduction to the COMS Meteorological Data Processing System Myoung-Hwan Ahn/RSRL 2005. 06. 02. CONTENTS. Introduction Baseline Products Examples Calibrations Future Plans. I. Introduction. 2009. 2008. 2007. 2006. 2005. 2004. 2003. 2002. 2001. 2000. 1999. 1998. 1997. 1996.

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Introduction to the COMS Meteorological Data Processing System Myoung-Hwan Ahn/RSRL 2005. 06. 02

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  1. Introduction to the COMS Meteorological Data Processing System Myoung-Hwan Ahn/RSRL 2005. 06. 02

  2. CONTENTS Introduction Baseline Products Examples Calibrations Future Plans

  3. I. Introduction

  4. 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 2003.9 COMS Project Kick-off 2000.12 National Plan for Long-term Space Development 1995.8 STEPI “Meteorological Sensors for Satellite 1997.11 “Research on the Korean Meteorological Satellite” 2000.3 “Project for Centennial Meteorological Events” 2000.8 Meteorological Satellite Forum 2001.4 Feasibility study for COMS Launch System Design Review Preliminary Design Review Critical Design Review Mission Readiness Review Pre Ship Review Data Service 2002.4 Preliminary work for COMS 1995 COMS

  5. Requirement of Ka-band Payload(TBC) Ka-band Service Coverage Frequency (Ka-band) Uplink : 29.6 ~ 30.0GHz Downlink : 19.6 ~ 20.3GHz Minimum EIRP edge of coverage 58dBW G/T 13dB/K Bandwidth 400MHz(100MHz/channel) Beamwidth 0.6degree/each beam Coverage Refer to right figure COMS Mission-1

  6. Ocean Sensor Coverage Item Requirements Spatial Resolution 500m X 500m Coverage 2,500km X 2,500km No. of Band 8 fixed band Band Center & Band Width & Nominal Rad.& Max Rad. & NEdL & SNR (Sensitivity of sensor) Band Center [nm] Band Width [nm] Nom. Rad [Wm-2 um-1sr-1] Max. Rad. [Wm-2um1sr-1] NEdL SNR 412 20 100 150.0 0.100 1000 443 20 92.5 145.8 0.085 1090 490 20 72.2 115.5 0.067 1170 555 20 55.3 85.2 0.056 1070 625 20 32.0 58.3 0.032 1010 670 20 27.1 46.2 0.031 870 765 40 17.7 33.0 0.020 860 865 40 12.0 23.4 0.016 750 MTF  0.3 at Nyquist frequency Dynamic Range  11bit Sensor Calibration - Calibration type : Solar Calibration - Accuracy of Radiometric Calibration :  3% Number of observation - Total : 8 times ∙ 10:00 ~ 17:00 : 6 times, ∙ 22:00, 02:00 : 2 times COMS Mission-2 Requirement of Ocean Sensor(TBC)

  7. COMS Mission-3 • Meteorology • Continuous monitoring of weather events with multi-channel Imager • Early detection of sever weather such as tropical cyclones, heavy rainfall, dust out break, etc. • Long term data acquisition for climate study • Channels

  8. Ka-band RF Signals HRIT/LRIT Meteorological Information Supply Command, Telemetry Communication System Monitoring Facility Raw Data, HRIT/LRIT Foreign Meteorological Data Receiving Station HRIT/LRIT Raw Data Various Site Satellite Operation Control Center / Back-up Data Processing Center Internet Internet Meteo/Ocean Data Application Center (Primary Data Processing Center) Exclusive Line Foreign Meteorological Organization / Foreign User Specialized Organization / Domestic User COMS System

  9. Unprocessed Cloud free land Cloud free sea Cloud contaminated Cloud filled Snow/Ice contaminated Unclassified CMDPS Pre-processing data Aux. Data, response function, etc. Validation Data Level 1.5 data Distribution Archive Applications Real Time Validation CMDPS CLD OLR Cloudy Clear CTP CType Fog SC/Ice SST TPW AMV AI PI

  10. CMDPS • COMS Meteorological Data Processing System (CMDPS) • System to produce geophysical parameters from the satellite measured raw radiance data. • The system includes; • algorithms for each baseline products • various auxiliary data such as the surface emissivity, etc. • radiative transfer model • calibration monitoring scheme and algorithm • interfaces for between algorithms, and between CMDPS and OS • validation procedures.

  11. II. Baseline Products

  12. Baseline products

  13. Baseline products 1 SFC includes the surface information acquired by both off-line and on-line

  14. COMS Level 1B Image data Auxiliary Data OLR Cloud Detection Cloudy Clear Sea Ice/Snow detection Aerosol Detection Cloud Phase Cloud Amount SST LST AOD AMV COD Cloud Type Insolation TPW UTH CTT&CTH PI Fog Baseline products OLR: Outgoing LW Radiation AOD: Aerosol optical depth COD: Cloud optical depth CTT: Cloud top temp. CTH: Cloud top height TPW: Total precipitable water UTH: Upper Tropospheric Humidity AMV: Atmospheric motion vector PI: Precipitation index

  15. III. Examples

  16. Baum et al.(2000, JGR) Cloud Phase-I • Key issues • Is WV channel useful for cloud phase • How accurate for multi-layer cloud ? • Approaches • Simulation • 8.7 vs. 6.3 • Application to MODIS data • comparison

  17. Cloud Phase-II

  18. Cloud Phase-III

  19. Cloud Removal LOOK UP TABLE METHOD a’s= F(q0 ,j 0,qs,ap) tb=0.0 … in 6S COMS Vis. Channel TOA Reflectance (a’p) COMS Vis. Channel TOA Reflectance (ap) RTM (6S) ta= F(q0 ,j 0,qs,ap,as) GOES-9 Vis. Channel Surface Reflectance (a’s) Look Up Table q0 = 0-70o ,5o j 0 = 0-180o ,10o qs= 0-70o ,5o ta = 0-3 ,0.1 as = 0-1, 0.1 as(1 month 2nd min. reflectance) AOD(ta) Aerosol Optical Depth-I

  20. Aerosol Optical Depth-II

  21. Aerosol Optical Depth-IV

  22. Aerosol Optical Depth-V

  23. Aerosol Optical Depth-VI Sources of uncertainty(Knapp et al., 2002)

  24. IV. Calibration

  25. Visible Channel Calibration-I • There is onboard calibrator for the infrared channels • There is no onboard calibrator for visible channel, although accurate calibration is required for the derivation quantitative values such as the aerosol optical depth and for climatic applications • For the real time monitoring/update of the visible channel calibration coefficients, we are going to take the vicarious calibration approach • The main concept for the approach originates from the current EUMETSAT visible channel calibration method, which compares the measured radiance and theoretically derived radiance • Thus, for the beginning, we builds up the theoretical model for the calculation of the theoretical radiance • Also, great efforts are given to find out bright and stable surface target for the determination of the slope of the calibration curve.

  26. (other Satellite) 16 days of Data COMSobservation COMS L1.5/2.0 ECMWF Target Identification Pixel extraction CLIMATE RTM (6S) Satellite level radiance Mean digitalcount Quality Control Calibration CalibrationCoefficient Visible Channel Calibration-II

  27. 6S(RTM) Input Data Geometry Solar Zenith and Azimuth Angles Sensor Zenith and Azimuth Angles Date Atmosphere Total Precipitable Water Total Ozone Aerosol Characteristics (Type, AOT) Target BRDF(Bidirectional Reflectance Distribution Function) Height Sensor Band, Response function Visible Channel Calibration-III

  28. R @ band 1 NDVI Normalized STDV of R @ Band 1 STDV of R @ Band 1 0.005 0.01 0.015 0.02 0.03 0.04 0.05 0.1 Visible Channel Calibration-IV

  29. Visible Channel Calibration-V 12Apr2004 0040

  30. Visible Channel Calibration-VI 3 X 3 grids average (0.1oX 0.1o) for TERRA MODIS Band01 [620~670nm] Error = R6S-RMODIS / RMODIS

  31. Visible Channel Calibration-VII

  32. Visible Channel Calibration-VIII • Other approaches • Using the bright cloud targets • Using the cloud albedo characteristics • Clear ocean targets with in-situ observation • Expected accuracy • Preliminary results show that absolute accuracy of 10% is relatively easily achieved • With well known surface characteristics of the target area, 5% is achievable • Further works are required for the characterization of uncertainty sources and reducing the uncertainty

  33. V. Future plan

  34. 2003 Conceptual Design 2004 Cal. concept S/W Development Simulation Data 2005 Cal. Development(I) S/W Prototype Interface design S/W Standardization Interface develop. Cal. Development(II) 2006 CMDPS Evaluation Data Integration to OS 2007 Validation 2008 Real time operation Future Plans • Other major Task • Development of validation strategy for the raw and derived products • Preparation for the user service

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