Download - Image Interpretation for Weather Analysis
Image Interpretation for Image Interpretation for Weather AnalysisWeather Analysis
Part IPart I11 November 200811 November 2008Dr. Steve DeckerDr. Steve Decker
Two KindsTwo Kinds
Polar OrbitingPolar Orbiting– Polar-orbiting Operational Environmental Polar-orbiting Operational Environmental
Satellite (POES)Satellite (POES) NOAA-18 (2005)NOAA-18 (2005) Two in operation at one timeTwo in operation at one time
– 2:00 and 7:302:00 and 7:30
GeostationaryGeostationary– Geostationary Operational Environmental Geostationary Operational Environmental
Satellite (GOES)Satellite (GOES)– How does a geostationary orbit work?How does a geostationary orbit work?
Meet the GOES SatellitesMeet the GOES Satellites GOES-8, 1994GOES-8, 1994
– Was GOES-East, now decommissionedWas GOES-East, now decommissioned GOES-9, 1995GOES-9, 1995
– Was GOES-West, then operated by Japan, now decommissionedWas GOES-West, then operated by Japan, now decommissioned GOES-10, 1997, 60GOES-10, 1997, 60°W°W
– Was GOES-West, now providing coverage for South AmericaWas GOES-West, now providing coverage for South America GOES-11, 2000, 135GOES-11, 2000, 135°W°W
– Current GOES-WestCurrent GOES-West GOES-12, 2001, 75GOES-12, 2001, 75°W°W
– Current GOES-EastCurrent GOES-East GOES-13, 2006GOES-13, 2006
Meet the GOES SatellitesMeet the GOES Satellites GOES-8, 1994GOES-8, 1994
– Was GOES-East, now decommissionedWas GOES-East, now decommissioned GOES-9, 1995, 160GOES-9, 1995, 160°E°E
– Was GOES-West, now operated by JapanWas GOES-West, now operated by Japan GOES-10, 1997, 60GOES-10, 1997, 60°W°W
– Was GOES-West, now providing coverage for South AmericaWas GOES-West, now providing coverage for South America GOES-11, 2000, 135GOES-11, 2000, 135°W°W
– Current GOES-WestCurrent GOES-West GOES-12, 2001, 75GOES-12, 2001, 75°W°W
– Current GOES-EastCurrent GOES-East GOES-13, 2006GOES-13, 2006
Meet the GOES SatellitesMeet the GOES Satellites GOES-8, 1994GOES-8, 1994
– Was GOES-East, now decommissionedWas GOES-East, now decommissioned GOES-9, 1995, 160GOES-9, 1995, 160°E°E
– Was GOES-West, now operated by JapanWas GOES-West, now operated by Japan GOES-10, 1997, 60GOES-10, 1997, 60°W°W
– Was GOES-West, now providing coverage for South AmericaWas GOES-West, now providing coverage for South America GOES-11, 2000, 135GOES-11, 2000, 135°W°W
– Current GOES-WestCurrent GOES-West GOES-12, 2001, 75GOES-12, 2001, 75°W°W
– Current GOES-EastCurrent GOES-East GOES-13, 2006GOES-13, 2006
Improvement ExampleImprovement Example
Registration GOES-12 vs. GOES-13Registration GOES-12 vs. GOES-13
GOES Image FrequencyGOES Image Frequency
Standard OperationsStandard Operations– Every 30 minutes for CONUSEvery 30 minutes for CONUS– Every three hours for full disk (takes 26 Every three hours for full disk (takes 26
minutes)minutes) Rapid Scan OperationsRapid Scan Operations
– Every 5 to 15 minutes for CONUSEvery 5 to 15 minutes for CONUS Super Rapid Scan OperationsSuper Rapid Scan Operations
– Every minute for small regionEvery minute for small region– Example: Example: Hurricane FrancesHurricane Frances
Common ChannelsCommon Channels
VisibleVisible– 0.65 0.65 μμm (red)m (red)
Infrared (IR)Infrared (IR)– 10.7 10.7 μμmm
Water VaporWater Vapor– 6.7 6.7 μμmm
Shortwave IRShortwave IR– 3.9 3.9 μμmm
Visible ChannelVisible Channel
Measures amount of sunlight reflectedMeasures amount of sunlight reflected– Approximates Earth’s albedoApproximates Earth’s albedo
CloudsClouds– Thick: High albedo Thick: High albedo White White– Thin: Moderate albedo Thin: Moderate albedo Light or medium gray Light or medium gray
Ocean: Low albedo Ocean: Low albedo Black Black Land: Variable albedo Land: Variable albedo Shades of gray Shades of gray
Sun Angle EffectsSun Angle Effects
Brightness varies by time of dayBrightness varies by time of day ““Terminator”: sunrise/sunset lineTerminator”: sunrise/sunset line Cloud shadowsCloud shadows
– Bumpy cloud top Bumpy cloud top lumpy depiction lumpy depiction– Flat cloud top Flat cloud top smooth depiction smooth depiction
SunglintSunglint– Brighter Brighter smoother sea smoother sea
Sun Angle EffectsSun Angle Effects
Brightness varies by time of dayBrightness varies by time of day ““Terminator”: sunrise/sunset lineTerminator”: sunrise/sunset line Cloud shadowsCloud shadows
– Bumpy cloud top Bumpy cloud top lumpy depiction lumpy depiction– Flat cloud top Flat cloud top smooth depiction smooth depiction
SunglintSunglint– Brighter Brighter smoother sea smoother sea
Infrared ChannelInfrared Channel
Amount of radiation received by satellite Amount of radiation received by satellite with with λλ=10.7 =10.7 μμmm
Combination of surface and cloud-top Combination of surface and cloud-top temperaturestemperatures
For monochrome images, colder For monochrome images, colder temperatures are brightertemperatures are brighter– Why?Why?
Snow vs low clouds vs landSnow vs low clouds vs land
IR EnhancementIR Enhancement
IR EnhancementIR Enhancement
IR EnhancementIR Enhancement
IR EnhancementIR Enhancement
IR EnhancementIR Enhancement
IR EnhancementIR Enhancement
Geographic FeaturesGeographic Features
Background for the weather featuresBackground for the weather features CoastsCoasts
– Vis: Sudden change from dark (ocean) to light Vis: Sudden change from dark (ocean) to light (land)(land)
– IR: At night, land is often colder (brighter) than IR: At night, land is often colder (brighter) than water. Vice versa during daytime.water. Vice versa during daytime.
LakesLakes– Vis: Shows ice-cover (bright)Vis: Shows ice-cover (bright)
Geographic FeaturesGeographic Features
Background for the weather featuresBackground for the weather features CoastsCoasts
– Vis: Sudden change from dark (ocean) to light Vis: Sudden change from dark (ocean) to light (land)(land)
– IR: At night, land is often colder (brighter) than IR: At night, land is often colder (brighter) than water. Vice versa during daytime.water. Vice versa during daytime.
LakesLakes– Vis: Shows ice-cover (bright)Vis: Shows ice-cover (bright)
Geographic FeaturesGeographic Features
Background for the weather featuresBackground for the weather features CoastsCoasts
– Vis: Sudden change from dark (ocean) to light Vis: Sudden change from dark (ocean) to light (land)(land)
– IR: At night, land is often colder (brighter) than IR: At night, land is often colder (brighter) than water. Vice versa during daytime.water. Vice versa during daytime.
LakesLakes– Vis: Shows ice-cover (bright)Vis: Shows ice-cover (bright)
Geographic FeaturesGeographic Features
Land typeLand type– Wooded Wooded Darker on Vis Darker on Vis– Sandy; little vegetation Sandy; little vegetation Brighter on Vis Brighter on Vis
Heat islandsHeat islands– Dark spots in IR at nightDark spots in IR at night
SnowSnow– Vis: Distinguishable from clouds in animationsVis: Distinguishable from clouds in animations– Vis: Brighter in treeless areasVis: Brighter in treeless areas
Geographic FeaturesGeographic Features
Land typeLand type– Wooded Wooded Darker on Vis Darker on Vis– Sandy; little vegetation Sandy; little vegetation Brighter on Vis Brighter on Vis
Heat islandsHeat islands– Dark spots in IR at nightDark spots in IR at night
SnowSnow– Vis: Distinguishable from clouds in animationsVis: Distinguishable from clouds in animations– Vis: Brighter in treeless areasVis: Brighter in treeless areas
Geographic FeaturesGeographic Features
Land typeLand type– Wooded Wooded Darker on Vis Darker on Vis– Sandy; little vegetation Sandy; little vegetation Brighter on Vis Brighter on Vis
Heat islandsHeat islands– Dark spots in IR at nightDark spots in IR at night
SnowSnow– Vis: Distinguishable from clouds in animationsVis: Distinguishable from clouds in animations– Vis: Brighter in treeless areasVis: Brighter in treeless areas
Cloud PatternsCloud Patterns Cloud shieldCloud shield
– Broad pattern with similar width in any directionBroad pattern with similar width in any direction Cloud bandCloud band
– Continuous formation with a distinct long axisContinuous formation with a distinct long axis Cloud lineCloud line
– Narrow cloud band (less than 60 n mi wide)Narrow cloud band (less than 60 n mi wide) Cloud streetCloud street
– Narrow cloud band with distinct elementsNarrow cloud band with distinct elements– Often come closely packed in parallelOften come closely packed in parallel
Cloud elementCloud element– Smallest resolvable cloud in imagerySmallest resolvable cloud in imagery
Comma cloudComma cloud– Spiraling cloud with at least one band, often shaped like a commaSpiraling cloud with at least one band, often shaped like a comma
Cloud StreetsCloud Streets
Animation for Comma CloudAnimation for Comma Cloud
Comma.fliComma.fli
Cloud IdentificationCloud Identification Compare visible and infrared imagesCompare visible and infrared images BrightnessBrightness
– Height and thicknessHeight and thickness TextureTexture
– Visible only; shadowsVisible only; shadows PatternPattern Edge definitionEdge definition SizeSize ShapeShape
Identifying Stratiform CloudsIdentifying Stratiform Clouds
StratusStratus– Smooth, flat tops; low altitudeSmooth, flat tops; low altitude– IR: Difficult to seeIR: Difficult to see– Vis: Often quite brightVis: Often quite bright
AltostratusAltostratus FogFog
– Difficult to distinguish from stratus using Vis and IRDifficult to distinguish from stratus using Vis and IR– Motionless; evaporates from outside inMotionless; evaporates from outside in– Valley fogValley fog
Identifying Stratiform CloudsIdentifying Stratiform Clouds
StratusStratus– Smooth, flat tops; low altitudeSmooth, flat tops; low altitude– IR: Difficult to seeIR: Difficult to see– Vis: Often quite brightVis: Often quite bright
AltostratusAltostratus FogFog
– Difficult to distinguish from stratus using Vis and IRDifficult to distinguish from stratus using Vis and IR– Motionless; evaporates from outside inMotionless; evaporates from outside in– Valley fogValley fog
Identifying Cumuliform CloudsIdentifying Cumuliform Clouds
CumulusCumulus– Vis: Medium bright; lumpyVis: Medium bright; lumpy– IR: Dark to medium gray; hard to see individual IR: Dark to medium gray; hard to see individual
elementselements
Identifying Cumuliform CloudsIdentifying Cumuliform Clouds
CumulusCumulus– Vis: Medium bright; lumpyVis: Medium bright; lumpy– IR: Dark to medium gray; hard to see individual IR: Dark to medium gray; hard to see individual
elementselements StratocumulusStratocumulus
– Vis: Bright; often cellularVis: Bright; often cellular– IR: Dark; can be hard to detectIR: Dark; can be hard to detect
Identifying Cumuliform CloudsIdentifying Cumuliform Clouds
CumulusCumulus– Vis: Medium bright; lumpyVis: Medium bright; lumpy– IR: Dark to medium gray; hard to see individual IR: Dark to medium gray; hard to see individual
elementselements StratocumulusStratocumulus
– Vis: Bright; often cellularVis: Bright; often cellular– IR: Dark; can be hard to detectIR: Dark; can be hard to detect
CumulonimbusCumulonimbus– Very bright in both Vis and IRVery bright in both Vis and IR
Identifying Cirriform CloudsIdentifying Cirriform Clouds
CirrusCirrus– Vis: Dark/medium gray; wispy; thinVis: Dark/medium gray; wispy; thin– IR: Light gray; not as fibrousIR: Light gray; not as fibrous
Identifying Cirriform CloudsIdentifying Cirriform Clouds
CirrusCirrus– Vis: Dark/medium gray; wispy; thinVis: Dark/medium gray; wispy; thin– IR: Light gray; not as fibrousIR: Light gray; not as fibrous
CirrostratusCirrostratus– Vis: Smooth; light gray; thickerVis: Smooth; light gray; thicker– IR: Light gray to whiteIR: Light gray to white
Identifying Cirriform CloudsIdentifying Cirriform Clouds
CirrusCirrus– Vis: Dark/medium gray; wispy; thinVis: Dark/medium gray; wispy; thin– IR: Light gray; not as fibrousIR: Light gray; not as fibrous
CirrostratusCirrostratus– Vis: Smooth; light gray; thickerVis: Smooth; light gray; thicker– IR: Light gray to whiteIR: Light gray to white
CirrocumulusCirrocumulus
Identifying Cirriform CloudsIdentifying Cirriform Clouds
CirrusCirrus– Vis: Dark/medium gray; wispy; thinVis: Dark/medium gray; wispy; thin– IR: Light gray; not as fibrousIR: Light gray; not as fibrous
CirrostratusCirrostratus– Vis: Smooth; light gray; thickerVis: Smooth; light gray; thicker– IR: Light gray to whiteIR: Light gray to white
CirrocumulusCirrocumulus Anvil CirrusAnvil Cirrus