Satellite Imagery Interpretation

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Satellite Imagery Interpretation

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The SKY

• Biggest lab in the world.

• Available to everyone.

• We view from below.

• Satellite views from above.

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Why Are Satellites Important?

• Monitor atmosphere, land surface, and oceans at multiple scales using a single instrument.

• Consistent global, high-resolution coverage over oceans, rugged terrain, and sparsely populated regions.

• Another observed data set in forecasters toolbox to help solve meteorology and hydrology problems.

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Satellite Types• Geostationary:

Same position near equator – same rotation speed as earth. Constant height – 36000 km (22,400 mi). Resolution - 1 km visible to 4-8 km IR and H2O channels.

• Polar Orbiting: Every orbit passes over the poles. Height around 850 km Scan earth in 2600 km wide swaths View same location twice at equator; overlaps toward

converging longitudes at poles. Resolution – 250 m (4 times more detail than GOES).

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Geostationary Satellite View

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Geostationary SatelliteGlobal Coverages

(1) GOES East (12) – 75W(2) GOES West (10) – 135W(3) MTSAT (Japan) – 135E(4) METEOSAT 5 – Indian Ocean(5) METEOSAT 8 – Europe - 0°

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Geostationary Satellite View

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Polar Orbit Viewing Earth

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Satellite Radiometers

• Measure radiation of different wavelengths in discrete intervals

• Intervals are called windows, channels or spectral bands

• GOES measures five spectral bands; one visible and four IR

• Use mirrors to scan a region• Transmit digital data to earth for processing

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GOES Satellite Basics• 5-channel Imager:

Visible (0.69 μm): Distinguish thick from thin clouds, identify snow, fog, smoke

Near-IR (3.9 μm): Distinguish water and ice clouds and cloud particle size

Water Vapor (6.7 μm): Upper-level wind patterns, atmosphere water content, specific moisture plumes

IR Window (10.7 μm): Temperature of cloud tops and ground surface

CO2 Absorption (13.2 μm): Cloud heights

• 19-channel Sounder: Provides hourly 10-km data to distinguish vertical temp and

moisture structure in the atmosphere

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Albedo

• Fraction of total radiation reflected by an object (surface).

• Varies according to: Cloud cover Particles in air Angle of sun’s rays Types of surface

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3.9 m

NIGHT DAY

Transparent

Reflected SolarRadiation

HIGH CLOUDS - ANVIL CIRRUS

(ice)

10.7 m

COLD

3.9m

relatively warm

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Thunderstorms

• Can see all scales of motion.

• Large complexes down to developing cumulus.

• Clouds outline moisture – shallow or deep.

• Identify boundaries.

• Causing severe signatures.

• Linear and clusters.

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Three biggest tornadoes inKiowa county. 2nd formedjust east of Greensburg and quickly grew to 2 mi in width!At least 2 smaller "satellite“tornadoes with the 1st tornadothat formed S of Greensburg.

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Steve Leach

Frances

13 14Aug. Charlie

Frances

Ivan

Jeanne

Jeanne

Florida’s Furiously Full Calendar!S

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Steve Leach

Courtesy: Palm Beach Post

Blowing Dust

• Hazard to visibility and breathing.

• Reveal wind patterns.

30Blowing Saharan Dust observed from SeaWifs: February 26, 2000

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MODIS Visible from Terra for 3-3-2004

moderate resolution imaging Spectroradiometer

DUST

FRONT

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Florida Fires

• Drought provided conditions.

• Several fires grew out of control.

• Several plumes caused Interstates to close.

• A close-up Ch2 (3.9 μm) shows “hotspots” from numerous fires.

34Band 2 2032z Image combined with 1302z-2032z Visible Loop

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Summary

• Satellite imagery is the “real world”, not model “fantasy” world.

• We see all atmospheric scales of motion in a single image.

• Satellite imagery interpretation is an art.• The imagery can help explain weather events.• We cannot start too soon (in school) educating

people in identifying features in the imagery.

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Local Visible Loops:http://www.rap.ucar.edu/weather/satellite/Geostationary Satellite Server:http://www.goes.noaa.gov/RAMSDIS online:http://www.cira.colostate.edu/RAMM/Rmsdsol/main.htmlNASA Global Hydrology and Climate Center:http://wwwghcc.msfc.nasa.gov/GOES/Space, Science and Engineering Center, U of Wisconsin, Madison:http://www.ssec.wisc.edu/data/GOES Status:http://www.oso.noaa.gov/goesstatus/POES Status:http://www.oso.noaa.gov/poesstatus/Sam Beckman web site:http://home.earthlink.net/~weateach/wxforecast.htm

Satellite Links