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The A-Train: Exploiting the Electromagnetic Spectrum

The A-Train: Exploiting the Electromagnetic Spectrum. Chip Trepte NASA Langley Research Center. What is the A-Train?. Constellation of satellites flying in formation to observe the same area and almost the same time but with using different techniques

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The A-Train: Exploiting the Electromagnetic Spectrum

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  1. The A-Train: Exploiting the Electromagnetic Spectrum Chip Trepte NASA Langley Research Center

  2. What is the A-Train? Constellation of satellites flying in formation to observe the same area and almost the same time but with using different techniques Orbit crosses equator around 1:30 pm local time or in the ‘Afternoon’ and (originally) lead by the Aqua mission Named after the ‘Take the A-Train’ jazz tune composed by Billy Stayhorn and made popular by Duke Ellington’s band. Data collected synchronously gives more-complete answers to important scientific questions than would be possible with observations collected at different times

  3. A-Train Members

  4. A-Train Instrument Techniques

  5. Basic Properties of Light Electromagnetic radiation propagates as a wave • oscillating electric and magnetic fields • theory provided by James Clerk Maxwell (1865) Three primary characteristics • intensity (amplitude of wave) • color (wavelength or frequency of wave) • polarity (propagation plane of wave)

  6. Electromagnetic Spectrum

  7. Attenuation of Light • Transmission of light through a substance is affected by the absorption and scattering of light. • August Beer (1854), Johann Lambert (1760) discovered this relationship

  8. Emission of Light Objects of different temperatures emit light that peak at different wavelengths • Hotter objects emits most radiation at shorter wavelengths • Cooler objects emit most radiation at longer wavelengths • Discovered by Wilhelm Wien (1893)

  9. Possible interactions between photons and molecules/atoms Visible and UV light: changes electron distribution in orbits (orbit transitions) Infrared light: changes vibration/rotation states Microwave light: changes rotation states

  10. Earth’s Atmosphere Limb View of Atmosphere: Troposphere – orange/yellow shades and contains > 80% of mass and holds almost all water and clouds Stratosphere – pinkish hue and where ozone layer exists Mesosphere and above – blueish hues

  11. Atmosphere Composition

  12. Atmospheric Aerosols/Particles • Particles or Aerosols are present throughout the atmosphere • pollen, dust, smoke ash, rain or sulphuric acid droplets • ice and snow crystals …… • Composed of many substances • water, ice, water/ice, • soluble gases, carbon cores … • Scatter light in many ways • geometric optics (rainbows, halos • Rayleigh (molecular) scattering • Mie scattering • Range in size 6 or 8 orders of magnitude (.01 microns to 10 cm) Lord Rayleigh Gustav Mie

  13. Techniques for Remote Sensing Detector Detector Light source Emission atmosphere Transmission Detector Source Detector Scattering from incoherent source Scattering from coherent source (Active Remote Sensing)

  14. OMI - SO2, ash, BrO TES - SO2 MLS - UTLS SO2, HCl, IWC Exploiting A-Train synergy for volcanic cloud studies Aura Aqua MODIS- SO2, ash, sulfate, ice AIRS - SO2, ash, sulfate, ice, SO2 profile CloudSat CPR – precipitation, hydrometeors CALIPSO CALIOP - aerosol altitude, phase/type The A-Train

  15. Soufrière Hills volcano (Montserrat) eruption, May 2006 ~0.2 Tg SO2 [Carn et al., 2007; Prata et al., 2007]

  16. Soufrière Hills volcano (Montserrat) eruption, May 2006 ~0.2 Tg SO2 [Carn et al., 2007; Prata et al., 2007]

  17. Soufrière Hills volcano (Montserrat) eruption, May 2006 ~0.2 Tg SO2 [Carn et al., 2007; Prata et al., 2007]

  18. Soufrière Hills volcano (Montserrat) eruption, May 2006 ~0.2 Tg SO2 [Carn et al., 2007; Prata et al., 2007]

  19. CALIPSO first light – 7 June 2006 OMI SO2 - 7 June 2006 OMI SO2 – 7 June 2006 CALIPSO ‘first light’ - 7 June 2006

  20. Clear air in Beijing Aqua-MODIS RGB October 4 2010

  21. Hazardous air in Beijing MODIS-RGB October 8 2010

  22. MODIS-RGB + Aura- OMI SO2 October 8 2010 SO2 pollution from coal burning Power Plants and industries (metal smelting)

  23. Combined CALIPSO/CloudSat Cloud Observations “Great Arc Cloud” MODIS 12 µm (Channel 32)

  24. 15 15 15 15 10 10 10 10 Height Height Height Height 5 5 5 5 0 0 0 0 CALIPSO 532 nm Backscatter CALIPSO 1064 nm Backscatter CloudSat Cloud Mask CloudSat Radar Reflectivity (dBZ)

  25. Aerosol and Cloud Observations over Southern Asia MODIS only October 25, 2006

  26. Aerosol and Cloud Observations over Southern Asia CALIPSO and MODIS October 25, 2006

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