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Geography 372 Introduction to Remote Sensing

Geography 372 Introduction to Remote Sensing. Slides from Michael King EOS Senior Project Scientist http://terra.nasa.gov/. Introduction to multispectral remote sensing. Slides from: Compton Tucker & Michael D. King Outline

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Geography 372 Introduction to Remote Sensing

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  1. Geography 372Introduction to Remote Sensing Slides from Michael King EOS Senior Project Scientist http://terra.nasa.gov/

  2. Introduction to multispectral remote sensing Slides from: Compton Tucker & Michael D. King Outline • Description of numerous kinds of optical systems for the remote sensing of the Earth from space • Cross-track (whiskbroom) scanning systems • Pushbroom scanning systems • Airborne and spaceborne multispectral whiskbroom and pushbroom scanners • MODIS, ETM+ (whiskbroom) • MISR, AirMISR (pushbroom) • Geometric characteristics of cross-track scanners • Hyperspectral scanners • Spectral reflectance of various land ecosystems and surfaces

  3. Cross-track, or Whiskbroom, Multispectral Scanner System Operation

  4. Instantaneous Field of View and Resulting Ground Area Sensed Directly Beneath an Aircraft by a Multi-spectral Scanner  = ifov (solid angle)

  5. Instantaneous Field of View and Resulting Ground Area Sensed Directly Beneath an Aircraft by a Multi-spectral Scanner  = scan angle

  6. Terra & Aqua • http://terra.nasa.gov/ • 5 instruments • ASTER • CERES • MISR • MODIS • MOPITT

  7. ASTER • The Advanced Spaceborne Thermal Emission and Reflection Radiometer obtains high-resolution (15 to 90 square meters per pixel) images of the Earth in 14 different wavelengths (Bands) of the electromagnetic spectrum, ranging from visible to thermal infrared light. • Scientists use ASTER data to create detailed maps of land surface temperature, emissivity, reflectance, and elevation. • ASTER is the only high spatial resolution instrument on the Terra platform. ASTER's ability to serve as a 'zoom' lens for the other Terra instruments is particularly important for change detection, calibration/validation and land surface studies

  8. ASTER

  9. ASTER Movie

  10. MODerate-resolution Imaging Spectroradiometer (MODIS) • NASA, Terra & Aqua • launches 1999, 2001 • 705 km polar orbits, descending (10:30 a.m.) & ascending (1:30 p.m.) • Sensor Characteristics • 36 spectral bands (490 detectors) ranging from 0.41 to 14.39 µm • Two-sided paddle wheel scan mirror with 2330 km swath width • Spatial resolutions: • 250 m (bands 1 - 2) • 500 m (bands 3 - 7) • 1000 m (bands 8 - 36) • 2% reflectance calibration accuracy • onboard solar diffuser & solar diffuser stability monitor • 12 bit dynamic range (0-4095)

  11. MODIS Onboard Calibrators Spectral Radiometric Calibration Assembly Solar Diffuser Blackbody Scan Mirror Space View Port Fold Mirror Nadir (+z)

  12. MODIS Optical System Visible Focal Plane SWIR/MWIR Focal Plane Scan Track NIR Focal Plane LWIR Focal Plane

  13. MODIS Movie

  14. 1st Day of Observations

  15. 9/17/2006 Northern California Fires

  16. MODIS Applications • Pg 243 of Text • Band 1 & 2 Land cover classification, chlorophyll absorption • Bands 3 - 7 Land, cloud & aerosol mapping • Bands 8 - 16 Ocean color, phytoplankton, biogeochemistry • Bands 17 - 19 Atmospheric water vapor • Bands 20-23 Surface-cloud temperature • Bands 24 & 25 Atmospheric temperature • Band 26 Cirrus Clouds • Bands 27 - 29 Water vapor • Bands 30 Ozone • Bands 31 & 32 Suface-cloud temperature • Bands 33 – 36 Cloud-top altitude

  17. Along-track, or Pushbroom, Multispectral System Operation

  18. NASA, EOS Terra Launched in 1999 polar, descending orbits of 705 km, 10:30 a.m. crossing Sensor Characteristics uses nine CCD-based push-broom cameras viewing nadir and fore & aft to 70.5° four spectral bands for each camera (36 channels), at 446, 558, 672, & 866 nm resolutions of 275 m, 550 m, or 1.1 km Advantages high spectral stability 9 viewing angles helps determine aerosol by µ dependence (fixed t) Multi-angle Imaging SpectroRadiometer (MISR)

  19. Orbital characteristics 400 km swath 9 day global coverage 7 min to observe each scene at all 9 look angles MISR Pushbroom Scanner • Family portrait • 9 MISR cameras • 1 AirMISR camera

  20. MISR Provides New Angle on Haze • In this MISR view spanning from Lake Ontario to Georgia, the increasingly oblique view angles reveal a pall of haze over the Appalachian Mountains

  21. MISR Provides New Angle on Haze • In this MISR view spanning from Lake Ontario to Georgia, the increasingly oblique view angles reveal a pall of haze over the Appalachian Mountains

  22. How do you select the Bandwidths?

  23. NASA ER-2

  24. AirMISR AirMISR Instrument in the Nose of the NASA ER-2 Aircraft

  25. MISR & AirMISR Simultaneously View South African Fires • In the MISR view on the left, the 45 aft view was used to image the Drakensberg Mountains (lower left), burn scars, and fires in South Africa (image 85 km x 200 km) • In the AirMISR view on the right, acquired nearly simultaneously from the NASA ER-2 aircraft as part of SAFARI 2000, the nadir view was used (image 9 km x 9 km) September 7, 2000 Burn scars

  26. Aerosol Effects on Reflected Solar Radiation over Land Biomass burning Cuiabá, Brazil (August 25, 1995) 10 km q0 = 36° R = 0.66 µm G = 0.55 µm B = 0.47 µm R = 1.65 µm G = 1.2 µm B = 2.1 µm 20 km AVIRIS Data

  27. MODIS Airborne Simulator

  28. Madikwe Fire 20 August 2000 24°44’S 26°13’E 0847 UTC Red = 0.66 µm Green = 0.55 µm Blue = 0.47 µm Flight Direction 36.0 km 6.4° q0 = 43.0° f0 = 33.8° f-f0 = 62.6° 36.0 km

  29. Madikwe Fire 20 August 2000 24°44’S 26°13’E 0847 UTC Red = 3.75 µm Green = 2.30 µm Blue = 1.64 µm Flight Direction 36.0 km 6.4° q0 = 43.0° f0 = 33.8° f-f0 = 62.6° 36.0 km

  30. 20 August 2000 24°44’S 26°13’E 0847 UTC Madikwe Fire q0 = 43.0° f0 = 33.8° f-f0 = 62.6° Red = 3.75 µm Green = 2.30 µm Blue = 1.64 µm Flight Direction 36.0 km 6.4° 36.0 km

  31. First Year Ice – Chukchi Sea 22 May 1998 72°14’N 157°07’W 2136 UTC Red = 2.13 µm Green = 1.62 µm Blue = 0.55 µm Flight Direction 37.2 km 166° q0 = 52.3° f0 = 165.5° f-f0 = 89.5° 37.2 km

  32. Stratus over Open Water 22 May 1998 71°14’N 157°27’W 2211 UTC Red = 2.13 µm Green = 1.62 µm Blue = 0.66 µm Flight Direction 37.2 km 348.2° q0 = 50.9° f0 = 175.4° f-f0 = 82.8° 37.2 km

  33. Stratus over Open Water 22 May 1998 71°14’N 157°27’W 2211 UTC l = 0.66 µm Flight Direction 37.2 km 348.2° q0 = 50.9° f0 = 175.4° f-f0 = 82.8° 37.2 km

  34. Stratus over Open Water 22 May 1998 71°14’N 157°27’W 2211 UTC l = 1.62 µm Flight Direction 37.2 km 348.2° q0 = 50.9° f0 = 175.4° f-f0 = 82.8° 37.2 km

  35. Source of Tangential Scale Distortion • Many airborne and spacecraft sensors have constant angular scanning • Image distortion along scan

  36. Tangential Scale Distortion in Unrectified Across-track Scanner Imagery Vertical aerial photograph Cross-track scanner image

  37. = qp yp ymax qmax yp qmax ymax Tangential Scale Distortion Correction qp = Yp = H¢tanqp

  38. Raw MAS Image of Point Barrow 3 June 1998 71°22’N 156°41’W 0106 UTC Red = 1.62 µm Green = 0.75 µm Blue = 0.47 µm Flight Direction 37.2 km 151.8° q0 = 54.2° f0 = 227.6° f-f0 = 165.8° 37.2 km

  39. Rectified MAS Image of Point Barrow 3 June 1998 71°22’N 156°41’W 0106 UTC Red = 1.62 µm Green = 0.75 µm Blue = 0.47 µm Flight Direction 37.2 km 151.8° q0 = 54.2° f0 = 227.6° f-f0 = 165.8° 37.2 km

  40. Resolution Cell Size Variation

  41. Across-track Scanner Imagery Distortions Induced by Aircraft Attitude Deviations

  42. Internal Blackbody Source Calibration

  43. Sample Calibration Curve Used to Correlate Scanner Output with Radiant Temperature Measured by a Radiometer e.g., 0, 1,35, 1002, Etc. Digital number Energy (w/m2)

  44. Sample Calibration Curve Used to Correlate Scanner Output with Radiant Temperature Measured by a Radiometer Energy->voltage->digital number W/m2

  45. The Imaging Spectrometry Concept

  46. MODIS/ASTER Airborne SimulatorIvanpah Playa, Mojave Desert, California 2.395 µm 0.945 µm 0.460 µm 1.625 µm Port 1 Port 2 25 120 20 100 15 Radiance Radiance 80 10 5 60 0.5 0.6 0.7 0.8 0.9 1.8 2.0 2.2 Wavelength (µm) Wavelength (µm)

  47. MODIS/ASTER Airborne SimulatorIvanpah Playa, Mojave Desert, California 5.25 µm 12.75 µm 3.15 µm 7.90 µm Port 3 Port 4 2.5 11 2.0 10 1.5 Radiance Radiance 9 1.0 8 0.5 7 3.5 4.0 4.5 5.0 8 9 10 11 12 Wavelength (µm) Wavelength (µm)

  48. Selected Laboratory Spectra of Minerals in the Shortwave Infrared • Spectra are displaced vertically to avoid overlap • The bandwidth of band 7 of the Landsat Thematic Mapper is also shown

  49. Selected Laboratory Spectra of Green Leaves • Spectra are displaced vertically to avoid overlap • The percent reflectance at 1.3 µm is provided for each spectrum

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