VIIRS Data Evaluation Over Thailand and Japan

February 13, 2012Chair, Chris Elvidge

NOAA-NGDCchris.elvidge@noaa.gov

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VIIRS – Visible Infrared Radiometer Suite• 1."VIIRS Overview, Status and Data Access" - Chris Elvidge, NOAA-USA•2."Comparsion of VIIRS and DMSP Nighttime Lights of Thailand" - Chris Elvidge, NOAA-USA•3."VIIRS Observations of Fires in Thailand" - Veerachai Tanpipat, Thailand•4."VIIRS Data of Japan" - Izumi Nagatani, MAFF-Japan

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VIIRS – Visible Infrared Radiometer Suite• Launched October 28, 2011 on the NPP satellite• NPP is the first in a series of planned weather & science satellites planned by the NASA – NOAA Joint Polar Satellite System (JPSS)• 16 moderate resolution (~1 km) spectral bands• 5 imaging bands (~400 m)• Low light imaging band (~750 m)• On-board calibration• 3000 km swath• Polar orbit• 1:30 and 13:30 overpasses• Daily and nightly global coverage• IR bands turned on January 18, 2012• NGDC serves as one of two long term archive sites for VIIRS data and products• HDF5 file format

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Improvements Coming for Nighttime LightsVIIRS vs OLS Basra, Iraq, December 5, 2012

•14 bit quantization•750 m GSD•~750 m GIFOV•1:30 am overpass•Radiometric calibration•No saturation

•6 bit quantization•2.7 km GSD•5 km+ GIFOV•8:00 pm overpass•No in-flight calibration•Saturation in urban center in operational data collections

Transect Across a Gas FlareVIIRS vs OLS Basra, Iraq, December 5, 2012

•14 bit quantization•750 m GSD•~750 m GIFOV•1:30 am overpass•Radiometric calibration•No saturation

•6 bit quantization•2.7 km GSD•5 km+ GIFOV•8:00 pm overpass•No in-flight calibration•Saturation in urban center in operational data collections

VIIRS DNB Issues and Proposed Solutions

• Bias in geolocation. Needs to be characterized to correct.• Geolocation lacks terrain correction. Use terrain corrected geolocation files from “I” bands.• Offsets were to be taken from new moon observation of deep ocean. However, derivation of the offsets complicated by scanline repeat cycle and detection of clouds by skyglow. Cloud-free compositing and synchronization of scanlines will be required to derive the best offsets.

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Bias in DNB Geolocation

VIIRS Data Access

•From the archive (www.class.noaa.gov). Open access anticipate in the next couple of months.• From direct readout stations. The direct broadcast service will start later this year.• From value added processors. NGDC will provide NRT and temporal composites of the DNB data. There will be other discipline based value added processors.