Chapter 9 Passive Remote Sensing Introduction to Remote Sensing Instructor: Dr. Cheng-Chien LiuCheng-Chien Liu Department of Earth Sciences National Cheng-Kung University Last updated: 16 December 2004

Introduction  Optical range  0.3  m~14  m Landsat series SPOT series High spatial resolution High spectral resolution

Landsat satellite program overview  Earth Resources Technology Satellite (ERTS) 1967 ERTS-1, 1972~1978 Nimbus weather satellite  modified Experimental system  test feasibility Open skies principle  Landsat-2, 1975 (ERTS-2)

Landsat satellite program overview (cont.)  Table 6.1: Characteristics of Landsat 1~6 Return Beam Vidicon (RBV) camera systems Multispectral Scanner system (MSS) Thematic Mapper (TM) Enhanced Thematic Mapper (ETM)  Table 6.2: Sensors used on Landsat 1~6 missions

Orbit characteristic of Landsat-1, -2, and –3  Fig 6.1: Landsat –1, -2, and –3 observatory configuration 3 m x 1.5 m, 4m width of solar panels, 815 kg, 900 km Inclination = 9 0 T o = 103 min/orbit  Fig 6.2: Typical Landsat-1, -2 and –3 daily orbit pattern Successive orbits are about 2760 km Swath: 185 km Orbital procession  18 days for coverage repetition  20 times of global coverage per year

Orbit characteristic of Landsat-1, -2, and –3 (cont.)  Sun-synchronous orbit 9:42 am  early morning skies are generally clearer than later in the day Pros: repeatable sun illumination conditions on the same day in every year Cons: variable sun illumination conditions with different locations and seasons  variations in atmospheric conditions

Sensors onboard Landsat-1, -2 and – 3  3-Channel RBV 185 km x 185 km Ground resolution: 80 m Spectral bands: 1:  m~0.575  m (green) 2:0.580  m~0.680  m (red) 3:  m~0.830  m (NIR) Expose  photosensitive surface  scan  video signal Pros:  Greater cartographic fidelity  Reseau grid  geometric correction in the recording process

Sensors onboard Landsat-1, -2 and – 3 (cont.)  3-Channel RBV (cont.) Landsat-1: malfunction  only 1690 scenes Landsat-2  only for engineering evaluation  only occasionally RBV imagery was obtained. Landsat-3  Single broad band (0.505~0.75 u  m)  2.6 times of resolution improved: 30 m  double f  Two-camera side-by-side configuration with side-lap and end-lap. (Fig 6.5)  Fig 6.6: Landsat-3 RBV image

Sensors onboard Landsat-1, -2 and – 3 (cont.)  4 Channel MSS 185 km x 185 km Ground resolution: 79 m Spectral band:  Band 4: 0.5  m ~ 0.6  m (green)  Band 5: 0.6  m ~ 0.7  m (red)  Band 6: 0.7  m ~ 0.8  m (NIR)  Band 7: 0.8  m ~ 0.9  m (NIR)  Band 8: 10.4~12.6 um  Landsat-3, failed  Band 4~7  band 1~4 in Landsat-4, -5  Fig 6.7: Comparison of spectral bands

Sensors onboard Landsat-1, -2 and – 3 (cont.)  4 Channel MSS (cont.) Fig 6.8: Landsat MSS operating configuration  Small TFOV  use an oscillating scan mirror A-to-D converter (6 bits)  Pixel width: 56 m x 79 m  set by the pixel sampling rate (Fig 6.9)  Each Landsat MSS scene  185 km x 185 km  2340 scan lines, 3240 pixels per line, 4 bands  Enormous data  Fig 6.10: Full-frame, band 5, Landsat MSS scene  Parallelogram  earth’s rotation  15 steps  Tick marks  Lat. Long.  Annotation block Color composite: band 4 (b), band 5 (g), band 7(r) (Fig 6.7)

Sensors onboard Landsat-1, -2 and – 3 (cont.)  Data distribution Experiment  transitional  operational NASA NOAA NASA USGS EOSAT USGS Landsat-1,-2,-3 Landsat-4,-5,-6 Landsat-7 Department of Interior Department of Commerce Department of Defense Data receiving station Data reprocessing Data catalogue

Orbit characteristics of Landsat-4 and -5  Fig 6.20: Sun-synchronous orbit of Landsat-4 and –5 Altitude: 900  705km  Retrievable by the space shuttle  Ground resolutions Inclination  T=99min  14.5 orbit/day 9:45 am Fig 6.21: adjacent orbit space = 2752 km 16-day repeat cycle 8-day phase between Landsat-4 and –5 (Fig 6.22)

Sensors onboard Landsat-4 and -5  Fig 6.23: Landsat-4 and –5 observatory configuration MSS, TM 2000 kg, 1.5x2.3m solar panels x 4 on one side High gain antenna  Tracking and Data Relay Satellite system (TDRSS) Direct transmission  X-band and S-band  MSS: 15 Mbps  TM: 85 Mbps

Sensors onboard Landsat-4 and –5 (cont.)  MSS Same as previous except for larger TFOV for keeping the same ground resolution (79 m  82 m ) Renumber bands  TM 7 bands (Table 6.3) DN: 6  8 bits Ground resolution: 30 m (thermal band: 120 m ) Geometric correction  Space Oblique Mercator (SOM) cartographic projection

Sensors onboard Landsat-4 and –5 (cont.)  TM (cont.) Bi-directional scan  the rate of oscillation of mirror dwelling time  geometric integrity signal-to-noise Detector:  MSS: 6x4=24  TM: 16x6+4x1=100 Fig 6.14: Thematic Mapper optical path and projection of IFOV on earth surface Fig 6.15: Schematic of TM scan line correction process

Landsat-6 planned mission  A failed mission  Enhanced Thematic Mapper (ETM) TM+ panchromatic band (0.5~0.9  m) with 15m resolution  pan sharpening Monolithic detector design  coregister Set 9-bit A-to-D converter to a high or low gain 8-bit setting from the ground.  Low reflectance  water  high gain  Bright region  deserts  low gain

Landsat-7  Launch: 1999  Web site:  Landsat 7 handbook Landsat 7 handbook Landsat 7 handbook  Landsat 7 in orbit Landsat 7 in orbit Landsat 7 in orbit  Depiction of Landsat 7 Depiction of Landsat 7 Depiction of Landsat 7

Landsat-7 (cont.)  Landsat 7 Orbit Orbital paths Swath Swath pattern  Landsat data

Landsat-7 (cont.)  Payload Enhanced Thematic Mapper Plus (ETM+)  Dual mode solar calibrator  Data transmission  TDRSS or stored on board.  GPS  subsequent geometric processing of the data High Resolution Multi-spectral Stereo Imager (HRMSI)  5 m panchromatic band  10 m ETM bands 1~4  Pointable  revisit time (<3 days) Stereo imaging.  0 0 ~38 0 cross-track and 0 0 ~30 0 along-track

Landsat-7 (cont.)  Application Monitoring Temperate Forests Mapping Volcanic Surface Deposits Three Dimensional Land Surface Simulations

Landsat TM Image interpretation  Pros: Spectral and radiometric resolution Ground resolution  Fig 6.26: MSS vs TM  Fig 6.27: All seven TM bands for a summertime image of an urban fringe area Lake, river, ponds: b1,2 > b3 > b4=b5=b7=0 Road urban streets: b4  min Agricultural crops: b4  max Golf courses

Landsat TM Image interpretation (cont.)  Fig 6.27 (cont.) Glacial ice movement: upper right  lower left  Drumlins, scoured bedrock hills  Band 7  resample from 120 m to 30 m  Plate 12 + Table 6.5: TM band color combinations (a): normal color  mapping of water sediment patterns (b): color infrared  mapping urban features and vegetation types (c)(d): false color

Landsat TM Image interpretation (cont.)  Fig 6.28: Landsat TM band 6 (thermal infrared) image Correlation with field observations  6 gray levels  6T  Plate 13: color-composite Landsat TM image Extremely hot  blackbody radiation  thermal infrared TM bands 3, 4 and 7

Landsat TM Image interpretation (cont.)  Fig 6.29: Landsat TM band 5 (mid- infrared) image Timber clear-cutting  Fig 6.30: Landsat TM band 3, 4 and 5 composite Extensive deforestation.  Fig 6.31: Landsat TM band 4 image map 13 individual TM scenes + mosaic

SPOT Satellite Program  Background French+Sweden+Belgium 1978 Commercially oriented program  SPOT-1 French Guiana, Ariane Rocket 1986 Linear array sensor+pushbroom scanning+pointable Full-scene stereoscopic imaging

SPOT Satellite Program (cont.)  SPOT  SPOT

Orbit characteristics of SPOT-1, -2 and -3  Orbit Circular, near-polar, sun-synchronous orbit Altitude: 832 km Inclination: Descend across the equator at 10:30AM Repeat: 26 days Fig 6.21: SPOT revisit pattern at latitude 45 0 and 0 0  At equator: 7 viewing opportunities exist  At 45 0 : 11 viewing opportunities exist

Sensors onboard SPOT-1, -2 and -3  Configuration (Fig 6.34) 2  2  3.5m, 1750 kg, solar panel: 15.6 m Modular design  High Resolution Visible (HRV) imaging system 2-mode  10m-resolution panchromatic mode (0.51~0.73  m)  20m-resolution color-infrared mode. (0.5~0.59  m, 0.61~0.68  m, 0.79~0.89  m)

Sensors onboard SPOT-1, -2 and –3 (cont.)  HRV (cont.) Pushbroom scanning  No moving part (mirror)  lifespan   Dwell time   Geometric error  4-CCD subarray  6000-element subarray  panchromatic mode, 10 m  Three 3000-element subarrays  multi-spectral mode, 20 m  8-bit, 25 Mbps Twin-HRV instruments  IFOV (for each instrument)   Swath: 60 km  km = 117 km (Fig 3.36)  TFOV (for each instrument)  27 0 =0.6 0  45 (Fig 3.35)

Sensors onboard SPOT-1, -2 and –3 (cont.)  HRV (cont.) Data streams  Although 2-mode can be operated simultaneously, only one mode data can be transmitted  limitation of data stream Stereoscopic imaging  Off-nadir viewing capability (Fig 6.37)  Frequency  revisit schedule (Fig 6.33)  Base-height ratio  latitude  0.75 at equator, 0.5 at 45 0 Control  Ground control station  Toulouse, France  observation sequence  Receiving station  Tordouse or Kiruna, Sweden  Tape recorded onboard  Transmitted within 2600 km -radius around the station

SPOT HRV image interpretation  Fig 6.38: SPOT-1 panchromatic image 10 m -resolution  Cf: Landsat MSS 80 m  Cf: Landsat TM 30 m (Fig 6.26)  Cf: Landsat ETM 15 m (Fig 6.32) Fig 6.39: SPOT-1 panchromatic image Plate14: merge of multispectral & panchromatic data Fig 6.40: SPOT-1 panchromatic image stereopair Plate 15: Perspective view of Alps  SPOT stereopair + parallax calculation  Plate 23 Fig 6.41: before and after the earthquake

SPOT –4 and –5  SPOT –4 Launched 1998 Vegetation Monitoring Instrument (VMI)  Swath: 2000 km  daily global coverage  Resolution: 1 km  Spectral band: b(0.43~0.47  m), g(0.5~0.59  m), r(0.61~0.68  m), N-IR(0.79~0.89  m), mid-IR(1.58~1.75  m)

SPOT –4 and –5 (cont.)  SPOT – 5 Launched 2002 Vegetation Monitoring Instrument (VMI)  Swath: 2000 km  daily global coverage  Resolution: 1 km  Spectral band: b(0.43~0.47  m), g(0.5~0.59  m), r(0.61~0.68  m), N-IR(0.79~0.89  m), mid-IR(1.58~1.75  m)

Earth Observing System  Mission to Planet Earth (MTPE) Aims: providing the observations, understanding, and modeling capabilities needed assess the impacts of natural events and human-induced activities on the earth’s environment Data and information system: acquire, archive and distribute the data and information collected about the earth Further international understanding of the earth as a system

Earth Observing System (cont.)  EOS (Table 6.19) ASTER CERES MISR MODIS MOPITT  MODIS (Table 6.20) Table 6.20 Terra: 2000 Aqua: 2002  ASTER (Table 6.21)

Hign-resolution satellite system  CORONA 1960 – 1972, declassified in 1995 KH-1 ~ KH-4B ~ KH-5  Camera + film  Band and resolution Web site: Impacts

Hign-resolution satellite system (cont.)  IKONOS IKONOS 1999 by Space imaging Bands and resolution  1 m -resolution  0.45 – 0.90  m  4 m -resolution  0.45 – 0.52  m  0.52 – 0.60  m  0.63 – 0.69  m  0.76 – 0.90  m Orbit: sun-synchronous Repeat coverage: 1.5 (1 m ) ~ 3 (4 m ) days

Hign-resolution satellite system (cont.)  OrbView–3 and –4 OrbView-2: SeaWiFS Will be launched soon! Similar bands and resolution as IKONOS  OrbView–4 200 spectral channels in the range 0.45 – 2.5  m at 8 m resolution

Hign-resolution satellite system (cont.)  QuickBird QuickBird 2001 by EarthWatch Inc. Bands and resolution  61 cm -resolution  0.45 – 0.89  m  2.44 m -resolution  0.45 – 0.52  m  0.52 – 0.60  m  0.63 – 0.69  m  0.76 – 0.89  m

Hyperspectral satellite system (cont.)  Earth Observing 1 (EO-1) Earth Observing 1 (EO-1) Earth Observing 1 (EO-1) NASA + USGS  21 November 2000  One-year technology validation/demonstration mission  Landsat Data Continuity Mission (LDCM) Hyperion ALI