Daily Global Daily Global Observations of the Observations of the

Earth: From AVHRR To Earth: From AVHRR To MODIS And On To VIIRSMODIS And On To VIIRS

Chris ElvidgeChris Elvidge

NOAA National Geophysical Data NOAA National Geophysical Data CenterCenter

chris.elvidge@noaa.govchris.elvidge@noaa.gov

MODIS Blue Marble – From MODIS Blue Marble – From GSFCGSFC

Why:Why:

• The earth systems are in constant The earth systems are in constant motion.motion.

• Long term daily observation of the Long term daily observation of the entire earth which can be used to entire earth which can be used to establish baselines, from which it is establish baselines, from which it is possible detect and measure regional possible detect and measure regional to global scale environmental to global scale environmental changes.changes.

How:How:

• Imaging sensors on polar orbiting satellites Imaging sensors on polar orbiting satellites provide consistent sun-synchronous provide consistent sun-synchronous observation of the earth at a spatial and observation of the earth at a spatial and spectral resolution suitable for observing:spectral resolution suitable for observing:– Clouds and aerosols.Clouds and aerosols.– Snow and ice.Snow and ice.– Ocean color and temperature.Ocean color and temperature.– Land surface, vegetation and fire. Land surface, vegetation and fire.

Disadvantages of Disadvantages of Geostationary Satellite Data:Geostationary Satellite Data:

• Orbits at 35,000 km make it difficult Orbits at 35,000 km make it difficult to acquire sub-kilometer resolution to acquire sub-kilometer resolution imagery.imagery.

• Global constellation with spectral Global constellation with spectral bands suitable for air, land, sea and bands suitable for air, land, sea and ice observations has not been ice observations has not been achieved.achieved.

• No polar coverage.No polar coverage.

Fourteen orbits per day – Fourteen orbits per day – global coverageglobal coverage

A Long Term Record Of Daily A Long Term Record Of Daily Global Observations of the Global Observations of the Earth:Earth:• AVHRR – Advanced Very High Resolution AVHRR – Advanced Very High Resolution

Radiometer flown on NOAA’s Polar Orbiting Radiometer flown on NOAA’s Polar Orbiting Environmental Satellites from 1978 to the Environmental Satellites from 1978 to the present.present.

• MODIS – MODerate resolution imaging MODIS – MODerate resolution imaging spectrometer flown on NASA Earth Observing spectrometer flown on NASA Earth Observing System (Terra and Aqua satellites since System (Terra and Aqua satellites since December 1999.December 1999.

• VIIRS – Visible Infrared Imaging Radiometer Suite VIIRS – Visible Infrared Imaging Radiometer Suite – to be flown on the NOAA-NASA-DOD National – to be flown on the NOAA-NASA-DOD National Polar Orbiting Environmental Satellite System Polar Orbiting Environmental Satellite System (NPOESS) with first launch expected in 2008-09.(NPOESS) with first launch expected in 2008-09.

Science Driven Improvements Science Driven Improvements From AVHRR - Spectral From AVHRR - Spectral ResolutionResolution

AVHRRFive BandsVis, NIR, MIR, and two TIR

MODIS36 Bands

VIIRS20 Bands

“The best of the MODIS

Bands.”

Science Driven Improvements Science Driven Improvements From AVHRR – Spatial From AVHRR – Spatial ResolutionResolution

AVHRRFour km

GACOne kmLAC &HRPT

MODISInternested

Bands at 250 m500 m

And 1 km

VIIRS15 bands at

800 mFive bandsAt 400 m

Science Driven Improvements Science Driven Improvements From AVHRR – Geolocation From AVHRR – Geolocation AccuracyAccuracy

AVHRRVariable.GCP’s

FrequentlyUtilized.

MODISSub-

Kilometer.

VIIRSSub-

Kilometer.

Science Driven Improvements Science Driven Improvements From AVHRR – Radiometric From AVHRR – Radiometric CalibrationCalibration

AVHRRInadequateOn-board

calibration.

MODISVery goodOn-board

Calibration.

VIIRSVery goodOn-board

calibration.

Raw Data Volume.Raw Data Volume.

AVHRR4 GB / day.

MODIS70 GB /day.

VIIRS150 GB / day.

Who Started Archiving Who Started Archiving AVHRR Data?AVHRR Data?•NASA. NOAA started its NASA. NOAA started its

archiving effort year’s later.archiving effort year’s later.

Who Pioneered the Who Pioneered the Non-Meteorological Non-Meteorological Applications For Applications For AVHRR Data?AVHRR Data?•NASA. NOAA focused on the NASA. NOAA focused on the

weather community, who weather community, who needed global observations in needed global observations in near real time.near real time.

MODIS ImageryMODIS ImageryIce, frozen land & cloudsIce, frozen land & clouds

MODIS Imagery MODIS Imagery British ColumbiaBritish Columbia

MODIS ImageryMODIS ImageryMozambuique ChannelMozambuique Channel

MODIS ImageryMODIS ImageryFloridaFlorida

SummarySummary

• NASA and NOAA have built a long record of NASA and NOAA have built a long record of daily global observations of the earth.daily global observations of the earth.

• The NASA-MODIS instrument provides data that The NASA-MODIS instrument provides data that are substantially better than the NOAA-AVHRR.are substantially better than the NOAA-AVHRR.

• The VIIRS instruments will continue MODIS style The VIIRS instruments will continue MODIS style observations into the next decade and beyond.observations into the next decade and beyond.

• Establishing and operating new archives for Establishing and operating new archives for MODIS and VIIRS for global environmental MODIS and VIIRS for global environmental change research would require a very large change research would require a very large effort in data transfer, data storage, and data effort in data transfer, data storage, and data processing.processing.