Nine Years of Atmospheric Remote Sensing with SCIAMACHY – Instrument Performance Gottwald, Krieg,  Lichtenberg , Slijkhuis...
Topics <ul><li>instrument  </li></ul><ul><li>operations </li></ul><ul><li>instrument status and performance  </li></ul><ul...
SCIAMACHY on ENVISAT 26 m    10 m    5 m Satellite dimensions 8.2 t Satellite mass 10 No. of instruments 100.6 min Orbit...
Instrument – Optical Assembly <ul><li>Level 1: </li></ul><ul><li>channels 1 & 2 (UV) </li></ul><ul><li>entrance optics </l...
Viewing Geometries <ul><ul><li>scientific </li></ul></ul><ul><ul><ul><li>nadir </li></ul></ul></ul><ul><ul><ul><li>limb </...
Instrument – Thermal Subsystems <ul><li>Optical Bench Module (OBM) </li></ul><ul><ul><li>cooled via RAD A </li></ul></ul><...
Operations <ul><li>instrument operations are </li></ul><ul><ul><li>continuous </li></ul></ul><ul><ul><li>highly autonomous...
<ul><li>instrument operation related information available via </li></ul><ul><li>http://atmos.caf.dlr.de/projects/scops/ <...
<ul><li>Thermal Systems: ATC and OBM Temperature </li></ul><ul><ul><li>only small orbital variation of T OBM </li></ul></u...
Thermal Systems: TC and Detector Temperatures <ul><ul><li>temperature control via TC heaters </li></ul></ul><ul><ul><li>TC...
Life Limited Items <ul><ul><li>mechanical items (neutral density filter, aperture stop, nadir calibration window) and ther...
<ul><li>Optics - Throughput </li></ul><ul><li>optical throughput channels 1-6 </li></ul><ul><ul><li>reduction of 3-4% per ...
<ul><ul><li>channels 6+, 7, 8: </li></ul></ul><ul><ul><ul><li>6% pixel loss / year    about 10-15% ‘good’ pixels by end 2...
Limb Tangent Height <ul><li>pointing knowledge essential for geolocation retrieval, particularly limb tangent heights </li...
<ul><ul><li>mission in nominal ENVISAT orbit ended 22 October 2010 </li></ul></ul>Mission Extension 2010-2013 <ul><ul><li>...
SCIAMACHY – Exploring the Changing Earth’s Atmosphere  <ul><ul><li>SCIAMACHY – The Need for Atmospheric Research from Spac...
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NineYearsofAtmosphericRemoteSensingwithSCIAMACHY-InstrumentPerformance.ppt

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NineYearsofAtmosphericRemoteSensingwithSCIAMACHY-InstrumentPerformance.ppt

  1. 1. Nine Years of Atmospheric Remote Sensing with SCIAMACHY – Instrument Performance Gottwald, Krieg, Lichtenberg , Slijkhuis – DLR-IMF No ël, Bramstedt, Bovensmann, von Savigny – IUP, Univ. of Bremen Snel, Krijger – SRON
  2. 2. Topics <ul><li>instrument </li></ul><ul><li>operations </li></ul><ul><li>instrument status and performance </li></ul><ul><li>mission extension </li></ul>
  3. 3. SCIAMACHY on ENVISAT 26 m  10 m  5 m Satellite dimensions 8.2 t Satellite mass 10 No. of instruments 100.6 min Orbit period 10 a.m. (sun-synchronous) Descending node crossing 800 km Mean altitude 98.5° Inclination ENVISAT nominal mission profile
  4. 4. Instrument – Optical Assembly <ul><li>Level 1: </li></ul><ul><li>channels 1 & 2 (UV) </li></ul><ul><li>entrance optics </li></ul><ul><li>calibration unit </li></ul><ul><li>pre-disperser prism </li></ul><ul><li>Level 2: </li></ul><ul><li>channels 3 & 4 (VIS) </li></ul><ul><li>channel 5 (NIR) </li></ul><ul><li>channels 6-8 (SWIR) </li></ul>
  5. 5. Viewing Geometries <ul><ul><li>scientific </li></ul></ul><ul><ul><ul><li>nadir </li></ul></ul></ul><ul><ul><ul><li>limb </li></ul></ul></ul><ul><ul><ul><li>sun occultation </li></ul></ul></ul><ul><ul><ul><li>moon occultation </li></ul></ul></ul><ul><ul><li>calibration & monitoring </li></ul></ul><ul><ul><ul><li>sun occultation </li></ul></ul></ul><ul><ul><ul><li>moon occultation </li></ul></ul></ul><ul><ul><ul><li>subsolar </li></ul></ul></ul><ul><ul><ul><li>internal calibration lamps (WLS, SLS) </li></ul></ul></ul>
  6. 6. Instrument – Thermal Subsystems <ul><li>Optical Bench Module (OBM) </li></ul><ul><ul><li>cooled via RAD A </li></ul></ul><ul><ul><li>T = -17.6°C to -18.2°C </li></ul></ul><ul><ul><li>active thermal control (ATC) </li></ul></ul><ul><li>detectors </li></ul><ul><ul><li>cooled via SCIAMACHY Radiant Cooler (SRC) </li></ul></ul><ul><ul><li>T  195 K – 230 K (channels 1-6) </li></ul></ul><ul><ul><li>T  140 K – 160 K (channels 7 & 8) </li></ul></ul><ul><ul><li>open loop heater control (TC) </li></ul></ul><ul><ul><li>detectors </li></ul></ul><ul><li>decontamination </li></ul><ul><ul><li>SRC cooling capacity may degrade because of contamination </li></ul></ul><ul><ul><li>decontamination heaters to raise T on reflecting surface (if needed) </li></ul></ul><ul><ul><li>decontamination brings T of OBM and detectors close to 0°C </li></ul></ul><ul><ul><li> contaminants are removed </li></ul></ul>
  7. 7. Operations <ul><li>instrument operations are </li></ul><ul><ul><li>continuous </li></ul></ul><ul><ul><li>highly autonomous </li></ul></ul><ul><ul><li>implemented in states and timelines </li></ul></ul><ul><ul><li>organised in mission scenarios </li></ul></ul><ul><li>limb/nadir on dayside </li></ul><ul><li>sun occultation each orbit </li></ul><ul><li>sub-solar every 3 rd day </li></ul><ul><li>moon occultation whenever possible </li></ul><ul><li>dedicated eclipse measurements </li></ul><ul><li>calibration&monitoring measurements on daily, weekly and monthly timescales </li></ul>
  8. 8. <ul><li>instrument operation related information available via </li></ul><ul><li>http://atmos.caf.dlr.de/projects/scops/ </li></ul>Instrument Status - Availability launch March 1, 2002 end nominal mission phase March 1, 2007
  9. 9. <ul><li>Thermal Systems: ATC and OBM Temperature </li></ul><ul><ul><li>only small orbital variation of T OBM </li></ul></ul><ul><ul><li>very stable orbital mean T OBM </li></ul></ul><ul><ul><li>ATC degradation compensated by heater power adjustment </li></ul></ul>
  10. 10. Thermal Systems: TC and Detector Temperatures <ul><ul><li>temperature control via TC heaters </li></ul></ul><ul><ul><li>TC system degrades </li></ul></ul><ul><ul><ul><li>detectors 1-6: 0.1-0.3 K / year </li></ul></ul></ul><ul><ul><ul><li>detectors 7 & 8: approx. 1 K </li></ul></ul></ul>ice layer effect
  11. 11. Life Limited Items <ul><ul><li>mechanical items (neutral density filter, aperture stop, nadir calibration window) and thermal item (cryogenic heatpipe) have assigned in-flight activation budgets </li></ul></ul><ul><ul><li>electrical items (WLS, SLS) have assigned in-flight switching budgets </li></ul></ul><ul><ul><li>operations concept goal is not to exceed LLI limits </li></ul></ul>
  12. 12. <ul><li>Optics - Throughput </li></ul><ul><li>optical throughput channels 1-6 </li></ul><ul><ul><li>reduction of 3-4% per year in UV </li></ul></ul><ul><ul><li>very stable in VIS, NIR & SWIR </li></ul></ul>solar eclipse
  13. 13. <ul><ul><li>channels 6+, 7, 8: </li></ul></ul><ul><ul><ul><li>6% pixel loss / year  about 10-15% ‘good’ pixels by end 2013 </li></ul></ul></ul><ul><ul><ul><li>in 7 & 8: throughput loss 1-2% / year due to ice layer (decontaminations are still an option to remove ice) </li></ul></ul></ul><ul><li>Detectors - Degradation </li></ul><ul><ul><li>channel 2: detector material degradation (2% sensitivity loss / year)  25% loss by end 2013 </li></ul></ul>
  14. 14. Limb Tangent Height <ul><li>pointing knowledge essential for geolocation retrieval, particularly limb tangent heights </li></ul><ul><li>continuos improvement over the mission lifetime: current limb tangent height accuracy about 0.002-0.003° = 120-150 m </li></ul>
  15. 15. <ul><ul><li>mission in nominal ENVISAT orbit ended 22 October 2010 </li></ul></ul>Mission Extension 2010-2013 <ul><ul><li>since then modified drifting orbit </li></ul></ul><ul><ul><ul><li>no inclination manoeuvres </li></ul></ul></ul><ul><ul><ul><li>altitude lowered by 17 km </li></ul></ul></ul><ul><ul><li>instrument configuration successfully adapted to new orbit </li></ul></ul><ul><ul><li>SCIAMACHY continues to deliver high quality data </li></ul></ul>
  16. 16. SCIAMACHY – Exploring the Changing Earth’s Atmosphere <ul><ul><li>SCIAMACHY – The Need for Atmospheric Research from Space </li></ul></ul><ul><ul><li>ENVISAT – SCIAMACHY’s Host </li></ul></ul><ul><ul><li>The Instrument </li></ul></ul><ul><ul><li>Instrument Operations </li></ul></ul><ul><ul><li>Calibration and Monitoring </li></ul></ul><ul><ul><li>SCIAMACHY In-Orbit Operations and Performance </li></ul></ul><ul><ul><li>From Radiation Fields to Atmospheric Concentrations – Retrieval of Geophysical Parameters </li></ul></ul><ul><ul><li>Data Processing and Products </li></ul></ul><ul><ul><li>Validation </li></ul></ul><ul><ul><li>SCIAMACHY’s View of the Changing Earth’s Environment </li></ul></ul>

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