Satellite Interpretation for Weather Analysis - PowerPoint - PowerPoint by ZyECgmN

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									Image Interpretation for
  Weather Analysis
           Part I
    11 November 2008
     Dr. Steve Decker
                    Two Kinds
 Polar Orbiting
  – Polar-orbiting Operational Environmental
    Satellite (POES)
      NOAA-18 (2005)
      Two in operation at one time
        – 2:00 and 7:30
 Geostationary
  – Geostationary Operational Environmental
    Satellite (GOES)
  – How does a geostationary orbit work?
      Meet the GOES Satellites
 GOES-8, 1994
  – Was GOES-East, now decommissioned
 GOES-9, 1995
  – Was GOES-West, then operated by Japan, now decommissioned
 GOES-10, 1997, 60°W
  – Was GOES-West, now providing coverage for South America
 GOES-11, 2000, 135°W
  – Current GOES-West
 GOES-12, 2001, 75°W
  – Current GOES-East
 GOES-13, 2006
      Meet the GOES Satellites
 GOES-8, 1994
  – Was GOES-East, now decommissioned
 GOES-9, 1995, 160°E
  – Was GOES-West, now operated by Japan
 GOES-10, 1997, 60°W
  – Was GOES-West, now providing coverage for South America
 GOES-11, 2000, 135°W
  – Current GOES-West
 GOES-12, 2001, 75°W
  – Current GOES-East
 GOES-13, 2006
      Meet the GOES Satellites
 GOES-8, 1994
  – Was GOES-East, now decommissioned
 GOES-9, 1995, 160°E
  – Was GOES-West, now operated by Japan
 GOES-10, 1997, 60°W
  – Was GOES-West, now providing coverage for South America
 GOES-11, 2000, 135°W
  – Current GOES-West
 GOES-12, 2001, 75°W
  – Current GOES-East
 GOES-13, 2006
      Improvement Example
 Registration GOES-12 vs. GOES-13
      GOES Image Frequency
 Standard Operations
  – Every 30 minutes for CONUS
  – Every three hours for full disk (takes 26
    minutes)
 Rapid Scan Operations
  – Every 5 to 15 minutes for CONUS
 Super Rapid Scan Operations
  – Every minute for small region
  – Example: Hurricane Frances
            Common Channels
 Visible
  – 0.65 μm (red)
 Infrared (IR)
  – 10.7 μm
 Water Vapor
  – 6.7 μm
 Shortwave IR
  – 3.9 μm
            Visible Channel
 Measures amount of sunlight reflected
  – Approximates Earth’s albedo
 Clouds
  – Thick: High albedo  White
  – Thin: Moderate albedo  Light or medium gray
 Ocean: Low albedo  Black
 Land: Variable albedo  Shades of gray
             Sun Angle Effects
 Brightness varies by time of day
 “Terminator”: sunrise/sunset line
 Cloud shadows
  – Bumpy cloud top  lumpy depiction
  – Flat cloud top  smooth depiction
 Sunglint
  – Brighter  smoother sea
             Sun Angle Effects
 Brightness varies by time of day
 “Terminator”: sunrise/sunset line
 Cloud shadows
  – Bumpy cloud top  lumpy depiction
  – Flat cloud top  smooth depiction
 Sunglint
  – Brighter  smoother sea
           Infrared Channel
 Amount of radiation received by satellite
  with λ=10.7 μm
 Combination of surface and cloud-top
  temperatures
 For monochrome images, colder
  temperatures are brighter
  – Why?
 Snow vs low clouds vs land
IR Enhancement
IR Enhancement
IR Enhancement
IR Enhancement
IR Enhancement
IR Enhancement
          Geographic Features
 Background for the weather features
 Coasts
  – Vis: Sudden change from dark (ocean) to light
    (land)
  – IR: At night, land is often colder (brighter) than
    water. Vice versa during daytime.
 Lakes
  – Vis: Shows ice-cover (bright)
          Geographic Features
 Background for the weather features
 Coasts
  – Vis: Sudden change from dark (ocean) to light
    (land)
  – IR: At night, land is often colder (brighter) than
    water. Vice versa during daytime.
 Lakes
  – Vis: Shows ice-cover (bright)
          Geographic Features
 Background for the weather features
 Coasts
  – Vis: Sudden change from dark (ocean) to light
    (land)
  – IR: At night, land is often colder (brighter) than
    water. Vice versa during daytime.
 Lakes
  – Vis: Shows ice-cover (bright)
Another Example
         Geographic Features
 Land type
  – Wooded  Darker on Vis
  – Sandy; little vegetation  Brighter on Vis
 Heat islands
  – Dark spots in IR at night
 Snow
  – Vis: Distinguishable from clouds in animations
  – Vis: Brighter in treeless areas
         Geographic Features
 Land type
  – Wooded  Darker on Vis
  – Sandy; little vegetation  Brighter on Vis
 Heat islands
  – Dark spots in IR at night
 Snow
  – Vis: Distinguishable from clouds in animations
  – Vis: Brighter in treeless areas
         Geographic Features
 Land type
  – Wooded  Darker on Vis
  – Sandy; little vegetation  Brighter on Vis
 Heat islands
  – Dark spots in IR at night
 Snow
  – Vis: Distinguishable from clouds in animations
  – Vis: Brighter in treeless areas
                   Cloud Patterns
 Cloud shield
   – Broad pattern with similar width in any direction
 Cloud band
   – Continuous formation with a distinct long axis
 Cloud line
   – Narrow cloud band (less than 60 n mi wide)
 Cloud street
   – Narrow cloud band with distinct elements
   – Often come closely packed in parallel
 Cloud element
   – Smallest resolvable cloud in imagery
 Comma cloud
   – Spiraling cloud with at least one band, often shaped like a comma
Cloud Streets
   Animation for Comma Cloud
 Comma.fli
             Cloud Identification
 Compare visible and infrared images
 Brightness
    – Height and thickness
 Texture
    – Visible only; shadows
   Pattern
   Edge definition
   Size
   Shape
    Identifying Stratiform Clouds
 Stratus
  – Smooth, flat tops; low altitude
  – IR: Difficult to see
  – Vis: Often quite bright
 Altostratus
 Fog
  – Difficult to distinguish from stratus using Vis and IR
  – Motionless; evaporates from outside in
  – Valley fog
    Identifying Stratiform Clouds
 Stratus
  – Smooth, flat tops; low altitude
  – IR: Difficult to see
  – Vis: Often quite bright
 Altostratus
 Fog
  – Difficult to distinguish from stratus using Vis and IR
  – Motionless; evaporates from outside in
  – Valley fog
  Identifying Cumuliform Clouds
 Cumulus
  – Vis: Medium bright; lumpy
  – IR: Dark to medium gray; hard to see individual
    elements
  Identifying Cumuliform Clouds
 Cumulus
  – Vis: Medium bright; lumpy
  – IR: Dark to medium gray; hard to see individual
    elements
 Stratocumulus
  – Vis: Bright; often cellular
  – IR: Dark; can be hard to detect
  Identifying Cumuliform Clouds
 Cumulus
  – Vis: Medium bright; lumpy
  – IR: Dark to medium gray; hard to see individual
    elements
 Stratocumulus
  – Vis: Bright; often cellular
  – IR: Dark; can be hard to detect
 Cumulonimbus
  – Very bright in both Vis and IR
    Identifying Cirriform Clouds
 Cirrus
  – Vis: Dark/medium gray; wispy; thin
  – IR: Light gray; not as fibrous
    Identifying Cirriform Clouds
 Cirrus
  – Vis: Dark/medium gray; wispy; thin
  – IR: Light gray; not as fibrous
 Cirrostratus
  – Vis: Smooth; light gray; thicker
  – IR: Light gray to white
    Identifying Cirriform Clouds
 Cirrus
  – Vis: Dark/medium gray; wispy; thin
  – IR: Light gray; not as fibrous
 Cirrostratus
  – Vis: Smooth; light gray; thicker
  – IR: Light gray to white
 Cirrocumulus
    Identifying Cirriform Clouds
 Cirrus
  – Vis: Dark/medium gray; wispy; thin
  – IR: Light gray; not as fibrous
 Cirrostratus
  – Vis: Smooth; light gray; thicker
  – IR: Light gray to white
 Cirrocumulus
 Anvil Cirrus

								
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