Earth resource satellites operating in the optical spectrum

1
Chapter 6

• Earth resource satellites operating in the
  optical spectrum
• Introduction to Remote Sensing
• Instructor Dr. Cheng-Chien Liu
• Department of Earth Sciences
• National Cheng-Kung University
• Last updated 28 May 2003

2
6.1 Introduction

• Remote sensing space exploration (RSSE) ?
  interest and application over a wider range of
  disciplines
• Current application
• New technology ? new or improved satellite/sensor
  ? new application
• The most important outcome of RSSE
• ? observing earth ? earth system

3
6.1 Introduction (cont.)

• This chapter ? optical range ? 0.3 m m14 m m
• Landsat
• Spot
• NOAA series

4
6.2 Early history of space imaging

• Ludwig Bahrmann (1891) New or improved apparatus
  for obtaining Birds eye photographic views
• Alfred Maul (1907) gyrostabilization
• Alfred Maul (1912) 41kg, 200mm x 250 mm, 790m
• 19461950 V2 rockets
• 1960 TIROS-1, early weather satellite
• Not just look at but also look through

5
6.2 Early history of space imaging (cont.)

• 1960s Mercury, Gemini, Apollo
• Alan Shepard, 1961, 70 mm, 150 photos
• John Glenn, 1962, 35 mm, 48 photos.
• Later Mercury missions 70 mm, 80 mm
• Gemini GT-4 mission formal experiment directed
  at geology
• Tectonics, volcanology, geomophology.
• 12,400 1100 photos
• Apollo 9 4 camera array, electrically triggered.
  140 sets of imagery

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6.2 Early history of space imaging (cont.)

• Skylab 1973
• Earth Resources Experiment Package (EREP)
• 6-camera multi-spectral array
• A long focal length earth terrain camera
• A 13-channel multispectral scanner
• A pointable spectroradiometer
• Two microwave systems.
• 35,000 images
• U.S.-USSR Apollo-Soyuz Test Project (ASTP)

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6.3 Landsat satellite program overview

• Earth Resources Technology Satellite (ERTS) 1967
• ERTS-1, 19721978
• Nimbus weather satellite ? modified
• Experimental system ? test feasibility
• Open skies principle
• Landsat-2, 1975 (ERTS-2)

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6.3 Landsat satellite program overview (cont.)

• Table 6.1 Characteristics of Landsat 16
• Return Beam Vidicon (RBV) camera systems
• Multispectral Scanner system (MSS)
• Thematic Mapper (TM)
• Enhanced Thematic Mapper (ETM)
• Table 6.2 Sensors used on Landsat 16 missions

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6.4 Orbit characteristic of Landsat-1, -2, and 3

• Fig 6.1 Landsat 1, -2, and 3 observatory
  configuration
• 3m x 1.5m, 4m width of solar panels, 815 kg, 900
  km
• Inclination 90
• To 103 min/orbit
• Fig 6.2 Typical Landsat-1, -2 and 3 daily orbit
  pattern
• Successive orbits are about 2760km
• Swath 185km
• Orbital procession ? 18 days for coverage
  repetition ?20 times of global coverage per year

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6.4 Orbit characteristic of Landsat-1, -2, and 3
(cont.)

• Sun-synchronous orbit
• 942 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

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6.5 Sensors onboard Landsat-1, -2 and 3

• 3-Channel RBV
• 185km x 185 km
• Ground resolution 80m
• Spectral bands 1 0.475 mm0.575 mm (green)
• 20.580 mm0.680
  mm (red)
• 3 0.690 mm0.830 mm (NIR)
• Expose ? photosensitive surface ? scan ? video
  signal
• Pros
• Greater cartographic fidelity
• Reseau grid ? geometric correction in the
  recording process

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6.5 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 (0.5050.75 u mm)
• 2.6 times of resolution improved 30m ? double f
• Two-camera side-by-side configuration with
  side-lap and end-lap. (Fig 6.4)
• Fig 6.5 Landsat-3 RBV image

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6.5 Sensors onboard Landsat-1, -2 and 3 (cont.)

• 4 Channel MSS
• 185km x 185km
• Ground resolution 79m
• Spectral band
• Band 4 0.5 mm 0.6 mm (green)
• Band 5 0.6 mm 0.7 mm (red)
• Band 6 0.7 mm 0.8 mm (NIR)
• Band 7 0.8 mm 0.9 mm (NIR)
• Band 8 10.412.6 um ? Landsat-3, failed
• Band 47 ? band 14 in Landsat-4, -5
• Fig 6.6 Comparison of spectral bands

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6.5 Sensors onboard Landsat-1, -2 and 3 (cont.)

• 4 Channel MSS (cont.)
• Fig 6.7 Landsat MSS operating configuration
• Small TFOV ? use an oscillating scan mirror
• A-to-D converter (6 bits)
• Pixel width 56m x 79m ? set by the pixel
  sampling rate (Fig 6.8)
• Each Landsat MSS scene ? 185km x 185km
• 2340 scan lines, 3240 pixels per line, 4 bands
• Enormous data
• Fig 6.9 Full-frame, band 5, Landsat MSS scene
• Parallelogram ? earths rotation
• 15 steps
• Tick marks ? Lat. Long.
• Annotation block
• Color composite band 4 (b), band 5 (g), band
  7(r)(Fig 6.6)

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6.5 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

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6.6 Landsat MSS image interpretation

• Applications
• agriculture, botany cartography, civil
  engineering, environmental monitoring, forestry,
  geography, geology, geophysics, land resources
  analysis, land use planning, oceanography, water
  resource analysis
• Comparison of Landsat airborne image
• Table 6.4
• Resolution
• Coverage
• Complementary not replacement
• 2-D, non-stereo mode

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6.6 Landsat MSS image interpretation (cont.)

• Characteristics of MSS image
• Effective resolution ? 79m, (30m for Landsat-3)
  but linear feature with sharp contrast can be
  seen
• 1-D displacement relief (in E-W direction)
• Limited area can be viewed in stereo ? study
  topographic
• High altitude low TFOV ? little RD ? planimeter
  map
• E.g. World Bank, USGS. DMA, petroleum company

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6.6 Landsat MSS image interpretation (cont.)

• Characteristics of MSS image (cont.)
• Band 5 (red) ? better atmospheric penetration ?
  detecting cultural features
• Band 4 (green) ? deep, clear water penetration
• Band 6, 7 ? lineating water bodies (dark)
• The largest single use of Landsat MSS data ?
  geologic studies ? band 5.7

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6.6 Landsat MSS image interpretation (cont.)

• Fig 6.10 four Landsat MSS bands
• Extent of the urban area (B4, 5, light)
• Major road (B4, 5 light, not B6, B7 dark)
• Airport
• Asphalt-surfaced runways
• Four major lakes and connected river (B6, 7 dark)
• mid-July ? algae ? green ? B4 similar to the
  surrounding agricultural land
• Agricultural field. (B5, 6, 7)
• Forest (B4, 5 dark) ? winter images are preferred

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6.6 Landsat MSS image interpretation (cont.)

• Fig 6.11 Landsat MSS band 5
• December image
• 20 cm snow covered ? all water bodies are frozen
• Snow covered upland and valley floors ? light
  tone
• Steep, tree-covered valley sides ? dark tone
• September image
• Identify forest area

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6.6 Landsat MSS image interpretation (cont.)

• A hit-or-miss proposition
• Some events leave lingering trace
• Fig 6.12 Landsat MSS band 7
• July image ? 200 m3/sec
• March image ? 1300 m3/sec ? once every four years
• Fig 6.13 Mississippi River Delta
• Silt flow but vague boundary ? band 5
• Delineation of the boundary ? band 7
• Fig 6.14 short-lived phenomena
• Active forest fire in Alaska
• Volcanic eruption on Kunashir Island

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6.6 Landsat MSS image interpretation (cont.)

• A hit-or-miss proposition (cont.)
• Fig 6.15 Extensive geologic features visible on
  MSS
• San Andreas fault, Six solid dots ? earthquake gt
  6.0
• Fig 6.16 Landsat MSS band 6
• 66-km-wide Manicouagan ring ? 212-million-year-old
  meteorite impact crater
• Fig 6.17 Landsat MSS images of Mt. St. Helens
  before and after its 1980 eruptions
• Fig 6.18 Landsat MSS image of Maritoba, Canada,
  showing tornado and hail scar
• Fig 6.19 Landsat MSS image of East kalimantan,
  Indonesia, showing tropical deforestation

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6.7 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 98.20 ?T99min ? 14.5 orbit/day
• 945 am
• Fig 6.21 adjacent orbit space 2752km
• 16-day repeat cycle
• 8-day phase between Landsat-4 and 5 (Fig 6.22)

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6.8 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

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6.8 Sensors onboard Landsat-4 and 5 (cont.)

• MSS
• Same as previous except for larger TFOV for
  keeping the same ground resolution (79m ? 82m)
• Renumber bands
• TM
• 7 bands (Table 6.4)
• DN 6 ? 8 bits
• Ground resolution 30m (thermal band 120m)
• Geometric correction ? Space Oblique Mercator
  (SOM) cartographic projection

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6.8 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 6x424
• TM 16x64x1100
• Fig 6.24 Thematic Mapper optical path and
  projection of IFOV on earth surface
• Fig 6.25 Schematic of TM scan line correction
  process

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6.9 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 gt b3 gt b4b5b70
• Road urban streets b4 ? min
• Agricultural crops b4 ? max
• Golf courses

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6.9 Landsat TM Image interpretation (cont.)

• Fig 6.27 (cont.)
• Glacial ice movement upper right ? lower left
• Drumlins, scoured bedrock hills
• Band 7 ? resample from 120m to 30m
• 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

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6.9 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

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6.9 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

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6.10 Landsat-6 planned mission

• A failed mission
• Enhanced Thematic Mapper (ETM)
• TM panchromatic band (0.50.9 mm) with 15m
  resolution.
• 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

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6.11 Landsat ETM image simulation

• Fig 6.32 Landsat ETM images

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6.12 Landsat-7

• Launch 1999
• Web site http//landsat.gsfc.nasa.gov
• Landsat 7 handbook
• Landsat 7 in orbit
• Depiction of Landsat 7

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6.12 Landsat-7 (cont.)

• Landsat 7 Orbit
• Orbital paths
• Swath
• Swath pattern
• Landsat data
• http//landsat.gsfc.nasa.gov/main/data.html

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6.12 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)
• 5m panchromatic band
• 10m ETM bands 14
• Pointable ? revisit time (lt3 days) Stereo
  imaging.
• 00380 cross-track and 00300 along-track

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6.12 Landsat-7 (cont.)

• Application
• Monitoring Temperate Forests
• Mapping Volcanic Surface Deposits
• Three Dimensional Land Surface Simulations

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6.13 SPOT Satellite Program

• Background
• FrenchSwedenBelgium
• 1978
• Commercially oriented program
• SPOT-1
• French Guiana, Ariane Rocket
• 1986
• Linear array sensorpushbroom scanningpointable
• Full-scene stereoscopic imaging

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6.13 SPOT Satellite Program (cont.)

• SPOT-2
• 1990
• SPOT-3
• 1993

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6.14 Orbit characteristics of SPOT-1, -2 and -3

• Orbit
• Circular, near-polar, sun-synchronous orbit
• Altitude 832km
• Inclination 98.70
• Descend across the equator at 1030AM
• Repeat 26 days
• Fig 6.33 SPOT revisit pattern at latitude 450
  and 00
• At equator 7 viewing opportunities exist
• At 450 11 viewing opportunities exist

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6.15 Sensors onboard SPOT-1, -2 and -3

• Configuration (Fig 6.34)
• 2?2?3.5m, 1750 kg, solar panel 15.6m
• Modular design
• High Resolution Visible (HRV) imaging system
• 2-mode
• 10m-resolution panchromatic mode (0.510.73mm)
• 20m-resolution color-infrared mode. (0.50.59mm,
  0.610.68mm, 0.790.89mm)

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6.15 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, 10m
• Three 3000-element subarrays ? multi-spectral
  mode, 20m
• 8-bit, 25 Mbps
• Twin-HRV instruments
• IFOV (for each instrument) ? 4.130
• Swath 60km ? 2 - 3km 117km (Fig 3.36)
• TFOV (for each instrument) ? 2700.60?45 (Fig
  3.35)

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6.15 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 450
• Control
• Ground control station ? Toulouse, France ?
  observation sequence
• Receiving station ? Tordouse or Kiruna, Sweden
• Tape recorded onboard
• Transmitted within 2600km-radius around the
  station

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6.16 SPOT HRV image interpretation

• Fig 6.38 SPOT-1 panchromatic image
• 10m-resolution
• Cf Landsat MSS 80m
• Cf Landsat TM 30m (Fig 6.26)
• Cf Landsat ETM 15m (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

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6.17 SPOT 4 and 5

• SPOT 4
• Launched 1998
• Vegetation Monitoring Instrument (VMI)
• Swath 2000km ? daily global coverage
• Resolution 1km
• Spectral band b(0.430.47mm), g(0.50.59mm),
  r(0.610.68mm), N-IR(0.790.89mm),
  mid-IR(1.581.75mm)

45
6.17 SPOT 4 and 5 (cont.)

• SPOT 5
• Launched 2002
• Vegetation Monitoring Instrument (VMI)
• Swath 2000km ? daily global coverage
• Resolution 1km
• Spectral band b(0.430.47mm), g(0.50.59mm),
  r(0.610.68mm), N-IR(0.790.89mm),
  mid-IR(1.581.75mm)

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6.18 Meteorological Satellite

• Metsats
• Coarse spatial resolution ? land-oriented system
• Very high temporal resolution of global coverage
• NOAA satellites ? sun-synchronous
• GOES ? geostationary ? 36,000km altitude
• DMSP

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6.18 Meteorological Satellite (cont.)

• NOAA satellites
• Advanced Very High Resolution Radiometer (AVHRR)
• NOAA 6 -12. (N-S)
• Even 730AM crossing time
• Odd 230 AM crossing time
• Table 6.6 characteristics of NOAA-6 -12
• Fig 6.42 Example coverage of the NOAA AVHRR
• Ground resolution 1.1km at nadir
• AVHRR data
• LAC
• GAC
• Fig 6.43 Comparison of Spectral sensitivity

48
6.18 Meteorological Satellite (cont.)

• NOAA satellites (cont.)
• Fig 6.44 AVHRR images
• A distortion ? wide angle of view
• B geometric correction
• Plate 16 NOAA AVHRR band 4 thermal image of the
  Great Lakes
• Fig 6.45 AVHRR images of the Mississippi Delta
• (a) present and past channels, future ?
  Atchafalaya
• (b) Channel1 (red), silky material ? visible
• (c) Channel2 (Near-IR), light tone ? higher
  drier
• (d) Channel4 (thermal IR) light tone ? cooler
• Plumes of cooler river water

49
6.18 Meteorological Satellite (cont.)

• NOAA satellites (cont.)
• Plate 17 springtime NOAA-8 AVHRR color composite
• Applications of AVHRR in monitoring vegetation
• Use Ch-1 (0.580.68 mm) and Ch-2 (0.731.10 mm)
• A simple vegetation index VICh2-Ch1
• Normalized difference vegetation index NDVI
  (Ch2-Ch1)/(Ch2Ch1)
• Vegetated areas ? large VI
• Clouds, water, snow ? negative VI
• Rock, Bare soil ? VI ? 0
• For global vegetation ? NDVI preferred ?
  compensate the charging illumination conditions
• Plate 18 color-coded NDVI
• Select the highest NDVI during that period

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6.18 Meteorological Satellite (cont.)

• NOAA satellites (cont.)
• Applications of AVHRR in monitoring vegetation
  (cont.)
• Applications vegetation seasonal dynamics at
  global and continental scale, tropical forest
  clearance, leaf area index measurement, biomass
  estimation, percentage ground cover
  determination, photosynthetically active
  radiation estimation
• Other factors that might influence NDVI
• Incident solar radiation
• Radiometric response of the sensor
• Atmospheric effect and viewing angle ? need
  further research

51
6.18 Meteorological Satellite (cont.)

• GOES (Geostationary Operational Environmental
  Satellites)
• NOAA NASA
• 1974
• 36,000km
• USRS, ESA, NSDA
• Fig 6.46 GOES 2 visible band (0.550.7 mm)
• Frequency 2/hour
• VI (daytime), IR (day and night)

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6.18 Meteorological Satellite (Cont.)

• Defense Meteorological Satellite Program (DMSP)
• 1973
• 0.41.1 mm (VIN-IR)
• Nighttime visible band ? tune the amplifiers
• Fig 6.47 DMSP nighttime image
• Fig 6.48 Maps of population distribution

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6.19 Ocean monitoring satellites

• Ocean ? Land
• 2/3, but comparatively little is know
• Seasat (see 8.9)
• Nimbus 7
• CZCS (Coastal Zone Color Scanner) 19781986
• Proof of concept mission
• Table 6.7 CZCS bands ? narrow bandwidth
• 825m resolution at nadir, 1566km swath
• Map phytoplankton concentrations and inorganic
  suspended matter
• N-IR ? separate water from land

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6.19 Ocean monitoring satellites (cont.)

• Japan
• Marine Observation Satellite (MOS)-1 1987
• MOS-1b 1990
• Table 6.8 Instruments included in MOS-1 and
  MOS-1b
• 4-Channel Multi-spectral Electronic Self-Scanning
  Radiometer (MESSR)
• 4-Channel Visible and Thermal Infrared Radiometer
  (VTIR)
• 2-Channel Microwave Scanning Radiometer (MSR)
• 909km altitude, revisit period17days

55
6.19 Ocean monitoring satellites (cont.)

• Sea-viewing Wide-Field-of-View Sensor (SeaWiFS)
• 8-channel across-track scanner (0.4020.885 mm)
• Ocean biogeochemistry
• NASA-orbital science corporation (OSC)
• 1998 date
• Data
• LAC 1.13km
• GAC 4.52km
• 705km altitude, 2800km swath

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6.20 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 earths 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

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6.20 Earth Observing System (cont.)

• EOS (Table 6.9)
• ASTER
• CERES
• MISR
• MODIS
• MOPITT
• MODIS (Table 6.10)
• Table 6.10
• Terra 2000
• Aqua 2002

58
6.21 Fine-resolution satellite system

• CORONA
• 1960 1972, declassified in 1995
• KH-1 KH-4B KH-5
• Camera film
• Band and resolution
• Web site http//earthexplorer.usgs.gov
• Impacts

59
6.21 Fine-resolution satellite system (cont.)

• IKONOS
• 1999 by Space imaging
• Bands and resolution
• 1m-resolution
• 0.45 0.90 mm
• 4m-resolution
• 0.45 0.52 mm
• 0.52 0.60 mm
• 0.63 0.69 mm
• 0.76 0.90 mm
• Orbit sun-synchronous
• Repeat coverage 1.5 (1m) 3 (4m) days

60
6.21 Fine-resolution satellite system (cont.)

• OrbView3 and 4
• http//www.orbimage.com
• OrbView-2 SeaWiFS
• Will be launched soon!
• Similar bands and resolution as IKONOS
• OrbView4
• 200 spectral channels in the range 0.45 2.5 m m
  at 8m resolution

61
6.21 Fine-resolution satellite system (cont.)

• QuickBird
• 2001 by EarthWatch Inc.
• Bands and resolution
• 61cm-resolution
• 0.45 0.89 mm
• 2.44m-resolution
• 0.45 0.52 mm
• 0.52 0.60 mm
• 0.63 0.69 mm
• 0.76 0.89 mm